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\title{Nuweb Version 0.87b \\ A Simple Literate Programming Tool}
\date{}
\author{Preston Briggs\thanks{This work has been supported by ARPA,
through ONR grant N00014-91-J-1989.} 
\\ \sl preston@cs.rice.edu
\\ HTML scrap generator by John D. Ramsdell
\\ \sl ramsdell@mitre.org}

\begin{document}
\pagenumbering{roman}
\maketitle
\tableofcontents

\chapter{Introduction}
\pagenumbering{arabic}

In 1984, Knuth introduced the idea of {\em literate programming\/} and
described a pair of tools to support the practise~\cite{knuth:84}.
His approach was to combine Pascal code with \TeX\ documentation to
produce a new language, \verb|WEB|, that offered programmers a superior
approach to programming. He wrote several programs in \verb|WEB|,
including \verb|weave| and \verb|tangle|, the programs used to support
literate programming.
The idea was that a programmer wrote one document, the web file, that
combined documentation (written in \TeX~\cite{texbook}) with code
(written in Pascal).

Running \verb|tangle| on the web file would produce a complete
Pascal program, ready for compilation by an ordinary Pascal compiler.
The primary function of \verb|tangle| is to allow the programmer to
present elements of the program in any desired order, regardless of
the restrictions imposed by the programming language. Thus, the
programmer is free to present his program in a top-down fashion,
bottom-up fashion, or whatever seems best in terms of promoting
understanding and maintenance.

Running \verb|weave| on the web file would produce a \TeX\ file, ready
to be processed by \TeX\@. The resulting document included a variety of
automatically generated indices and cross-references that made it much
easier to navigate the code. Additionally, all of the code sections
were automatically pretty printed, resulting in a quite impressive
document. 

Knuth also wrote the programs for \TeX\ and {\small\sf METAFONT}
entirely in \verb|WEB|, eventually publishing them in book
form~\cite{tex:program,metafont:program}. These are probably the
largest programs ever published in a readable form.

Inspired by Knuth's example, many people have experimented with
\verb|WEB|\@. Some people have even built web-like tools for their
own favorite combinations of programming language and typesetting
language. For example, \verb|CWEB|, Knuth's current system of choice,
works with a combination of C (or C++) and \TeX~\cite{levy:90}.
Another system, FunnelWeb, is independent of any programming language
and only mildly dependent on \TeX~\cite{funnelweb}. Inspired by the
versatility of FunnelWeb and by the daunting size of its
documentation, I decided to write my own, very simple, tool for
literate programming.%
\footnote{There is another system similar to
mine, written by Norman Ramsey, called {\em noweb}~\cite{noweb}. It
perhaps suffers from being overly Unix-dependent and requiring several
programs to use. On the other hand, its command syntax is very nice.
In any case, nuweb certainly owes its name and a number of features to
his inspiration.}


\section{Nuweb}

Nuweb works with any programming language and \LaTeX~\cite{latex}. I
wanted to use \LaTeX\ because it supports a multi-level sectioning
scheme and has facilities for drawing figures. I wanted to be able to
work with arbitrary programming languages because my friends and I
write programs in many languages (and sometimes combinations of
several languages), {\em e.g.,} C, Fortran, C++, yacc, lex, Scheme,
assembly, Postscript, and so forth. The need to support arbitrary
programming languages has many consequences:
\begin{description}
\item[No pretty printing] Both \verb|WEB| and \verb|CWEB| are able to
  pretty print the code sections of their documents because they
  understand the language well enough to parse it. Since we want to use
  {\em any\/} language, we've got to abandon this feature.
\item[No index of identifiers] Because \verb|WEB| knows about Pascal,
  it is able to construct an index of all the identifiers occurring in
  the code sections (filtering out keywords and the standard type
  identifiers). Unfortunately, this isn't as easy in our case. We don't
  know what an identifiers looks like in each language and we certainly
  don't know all the keywords. (On the other hand, see the end of
  Section~1.3)
\end{description}
Of course, we've got to have some compensation for our losses or the
whole idea would be a waste. Here are the advantages I can see:
\begin{description}
\item[Simplicity] The majority of the commands in \verb|WEB| are
  concerned with control of the automatic pretty printing. Since we
  don't pretty print, many commands are eliminated. A further set of
  commands is subsumed by \LaTeX\  and may also be eliminated. As a
  result, our set of commands is reduced to only four members (explained
  in the next section). This simplicity is also reflected in
  the size of this tool, which is quite a bit smaller than the tools
  used with other approaches.
\item[No pretty printing] Everyone disagrees about how their code
  should look, so automatic formatting annoys many people. One approach
  is to provide ways to control the formatting. Our approach is
  simpler---we perform no automatic formatting and therefore allow the
  programmer complete control of code layout.
\item[Control] We also offer the programmer complete control of the
  layout of his output files (the files generated during tangling). Of
  course, this is essential for languages that are sensitive to layout;
  but it is also important in many practical situations, {\em e.g.,}
  debugging.
\item[Speed] Since nuweb doesn't do to much, the nuweb tool runs
  quickly. I combine the functions of \verb|tangle| and \verb|weave| into
  a single program that performs both functions at once.
\item[Page numbers] Inspired by the example of noweb, nuweb refers to
  all scraps by page number to simplify navigation. If there are
  multiple scraps on a page (say page~17), they are distinguished by
  lower-case letters ({\em e.g.,} 17a, 17b, and so forth).
\item[Multiple file output] The programmer may specify more than one
  output file in a single nuweb file. This is required when constructing
  programs in a combination of languages (say, Fortran and C)\@. It's also
  an advantage when constructing very large programs that would require
  a lot of compile time.
\end{description}
This last point is very important. By allowing the creation of
multiple output files, we avoid the need for monolithic programs.
Thus we support the creation of very large programs by groups of
people. 

A further reduction in compilation time is achieved by first
writing each output file to a temporary location, then comparing the
temporary file with the old version of the file. If there is no
difference, the temporary file can be deleted. If the files differ,
the old version is deleted and the temporary file renamed. This
approach works well in combination with \verb|make| (or similar tools),
since \verb|make| will avoid recompiling untouched output files.

\subsection{Nuweb and HTML}

In addition to producing {\LaTeX} source, nuweb can be used to
generate HyperText Markup Language (HTML), the markup language used by
the World Wide Web.  HTML provides hypertext links.  When a HTML
document is viewed online, a user can navigate within the document by
activating the links.  The tools which generate HTML automatically
produce hypertext links from a nuweb source.


\section{Writing Nuweb}

The bulk of a nuweb file will be ordinary \LaTeX\@. In fact, any
{\LaTeX} file can serve as input to nuweb and will be simply copied
through unchanged to the documentation file---unless a nuweb command
is discovered. All nuweb commands begin with an ``at-sign''
(\verb|@|).  Therefore, a file without at-signs will be copied
unchanged.  Nuweb commands are used to specify {\em output files,}
define {\em macros,} and delimit {\em scraps}. These are the basic
features of interest to the nuweb tool---all else is simply text to be
copied to the documentation file.

\subsection{The Major Commands}

Files and macros are defined with the following commands:
\begin{description}
\item[{\tt @o} {\em file-name flags scrap\/}] Output a file. The file name is
  terminated by whitespace.
\item[{\tt @d} {\em macro-name scrap\/}] Define a macro. The macro name
  is terminated by a return or the beginning of a scrap.
\end{description}
A specific file may be specified several times, with each definition
being written out, one after the other, in the order they appear.
The definitions of macros may be similarly divided.

\subsubsection{Scraps}

Scraps have specific begin markers and end markers to allow precise
control over the contents and layout. Note that any amount of
whitespace (including carriage returns) may appear between a name and
the beginning of a scrap.
\begin{description}
\item[\tt @\{{\em anything\/}@\}] where the scrap body includes every
  character in {\em anything\/}---all the blanks, all the tabs, all the
  carriage returns.
\end{description}
Inside a scrap, we may invoke a macro.
\begin{description}
\item[\tt @<{\em macro-name\/}@>] Causes the macro 
  {\em macro-name\/} to be expanded inline as the code is written out
  to a file. It is an error to specify recursive macro invocations.
\end{description}
Note that macro names may be abbreviated, either during invocation or
definition. For example, it would be very tedious to have to
repeatedly type the macro name
\begin{quote}
\verb|@d Check for terminating at-sequence and return name if found|
\end{quote}
Therefore, we provide a mechanism (stolen from Knuth) of indicating
abbreviated names.
\begin{quote}
\verb|@d Check for terminating...|
\end{quote}
Basically, the programmer need only type enough characters to uniquely
identify the macro name, followed by three periods. An abbreviation
may even occur before the full version; nuweb simply preserves the
longest version of a macro name. Note also that blanks and tabs are
insignificant in a macro name; any string of them are replaced by a
single blank.

When scraps are written to a program file or a documentation file, tabs are
expanded into spaces by default. Currently, I assume tab stops are set
every eight characters. Furthermore, when a macro is expanded in a scrap,
the body of the macro is indented to match the indentation of the
macro invocation. Therefore, care must be taken with languages 
({\em e.g.,} Fortran) that are sensitive to indentation.
These default behaviors may be changed for each output file (see
below).

\subsubsection{Flags}

When defining an output file, the programmer has the option of using
flags to control output of a particular file. The flags are intended
to make life a little easier for programmers using certain languages.
They introduce little language dependences; however, they do so only
for a particular file. Thus it is still easy to mix languages within a
single document. There are three ``per-file'' flags:
\begin{description}
\item[\tt -d] Forces the creation of \verb|#line| directives in the
  output file. These are useful with C (and sometimes C++ and Fortran) on
  many Unix systems since they cause the compiler's error messages to
  refer to the web file rather than the output file. Similarly, they
  allow source debugging in terms of the web file.
\item[\tt -i] Suppresses the indentation of macros. That is, when a
  macro is expanded in a scrap, it will {\em not\/} be indented to
  match the indentation of the macro invocation. This flag would seem
  most useful for Fortran programmers.
\item[\tt -t] Suppresses expansion of tabs in the output file. This
  feature seems important when generating \verb|make| files.
\end{description}


\subsection{The Minor Commands}

We have two very low-level utility commands that may appear anywhere
in the web file.
\begin{description}
\item[\tt @@] Causes a single ``at sign'' to be copied into the output.
\item[\tt @i {\em file-name\/}] Includes a file. Includes may be
  nested, though there is currently a limit of 10~levels. The file name
  should be complete (no extension will be appended) and should be
  terminated by a carriage return.
\end{description}
Finally, there are three commands used to create indices to the macro
names, file definitions, and user-specified identifiers.
\begin{description}
\item[\tt @f] Create an index of file names.
\item[\tt @m] Create an index of macro name.
\item[\tt @u] Create an index of user-specified identifiers.
\end{description}
I usually put these in their own section
in the \LaTeX\ document; for example, see Chapter~\ref{indices}.

Identifiers must be explicitly specified for inclusion in the
\verb|@u| index. By convention, each identifier is marked at the
point of its definition; all references to each identifier (inside
scraps) will be discovered automatically. To ``mark'' an identifier
for inclusion in the index, we must mention it at the end of a scrap.
For example,
\begin{quote}
\begin{verbatim}
@d a scrap @{
Let's pretend we're declaring the variables FOO and BAR
inside this scrap.
@| FOO BAR @}
\end{verbatim}
\end{quote}
I've used alphabetic identifiers in this example, but any string of
characters (not including whitespace or \verb|@| characters) will do.
Therefore, it's possible to add index entries for things like
\verb|<<=| if desired. An identifier may be declared in more than one
scrap.

In the generated index, each identifier appears with a list of all the
scraps using and defining it, where the defining scraps are
distinguished by underlining. Note that the identifier doesn't
actually have to appear in the defining scrap; it just has to be in
the list of definitions at the end of a scrap.


\section{Running Nuweb}

Nuweb is invoked using the following command:
\begin{quote}
{\tt nuweb} {\em flags file-name}\ldots
\end{quote}
One or more files may be processed at a time. If a file name has no
extension, \verb|.w| will be appended.  {\LaTeX} suitable for
translation into HTML by {\LaTeX}2HTML will be produced from
files whose name ends with \verb|.hw|, otherwise, ordinary {\LaTeX} will be
produced.  While a file name may specify a file in another directory,
the resulting documentation file will always be created in the current
directory. For example,
\begin{quote}
{\tt nuweb /foo/bar/quux}
\end{quote}
will take as input the file \verb|/foo/bar/quux.w| and will create the
file \verb|quux.tex| in the current directory.

By default, nuweb performs both tangling and weaving at the same time.
Normally, this is not a bottleneck in the compilation process;
however, it's possible to achieve slightly faster throughput by
avoiding one or another of the default functions using command-line
flags. There are currently three possible flags:
\begin{description}
\item[\tt -t] Suppress generation of the documentation file.
\item[\tt -o] Suppress generation of the output files.
\item[\tt -c] Avoid testing output files for change before updating them.
\end{description}
Thus, the command
\begin{quote}
\verb|nuweb -to /foo/bar/quux|
\end{quote}
would simply scan the input and produce no output at all.

There are two additional command-line flags:
\begin{description}
\item[\tt -v] For ``verbose,'' causes nuweb to write information about
  its progress to \verb|stderr|.
\item[\tt -n] Forces scraps to be numbered sequentially from~1
  (instead of using page numbers). This form is perhaps more desirable
  for small webs.
\end{description}

\section{Generating HTML}

Nikos Drakos' {\LaTeX}2HTML Version 0.5.3~\cite{drakos:94} can be used
to translate {\LaTeX} with embedded HTML scraps into HTML\@.  Be sure
to include the document-style option \verb|html| so that {\LaTeX} will
understand the hypertext commands.  When translating into HTML, do not
allow a document to be split by specifying ``\verb|-split 0|''.  
You need not generate navigation links, so also specify
``\verb|-no_navigation|''.

While preparing a web, you may want to view the program's scraps without
taking the time to run {\LaTeX}2HTML\@.  Simply rename the generated
{\LaTeX} source so that its file name ends with \verb|.html|, and view
that file.  The documentations section will be jumbled, but the
scraps will be clear.

\section{Restrictions}

Because nuweb is intended to be a simple tool, I've established a few
restrictions. Over time, some of these may be eliminated; others seem
fundamental.
\begin{itemize}
\item The handling of errors is not completely ideal. In some cases, I
  simply warn of a problem and continue; in other cases I halt
  immediately. This behavior should be regularized.
\item I warn about references to macros that haven't been defined, but
  don't halt. This seems most convenient for development, but may change
  in the future.
\item File names and index entries should not contain any \verb|@|
  signs.
\item Macro names may be (almost) any well-formed \TeX\ string.
  It makes sense to change fonts or use math mode; however, care should
  be taken to ensure matching braces, brackets, and dollar signs.
  When producing HTML, macros are displayed in a preformatted element
  (PRE), so macros may contain one or more A, B, I, U, or P elements
  or data characters.
\item Anything is allowed in the body of a scrap; however, very
  long scraps (horizontally or vertically) may not typeset well.
\item Temporary files (created for comparison to the eventual
  output files) are placed in the current directory. Since they may be
  renamed to an output file name, all the output files should be on the
  same file system as the current directory.
\item Because page numbers cannot be determined until the document has
  been typeset, we have to rerun nuweb after \LaTeX\ to obtain a clean
  version of the document (very similar to the way we sometimes have
  to rerun \LaTeX\ to obtain an up-to-date table of contents after
  significant edits).  Nuweb will warn (in most cases) when this needs
  to be done; in the remaining cases, \LaTeX\ will warn that labels
  may have changed.
\end{itemize}
Very long scraps may be allowed to break across a page if declared
with \verb|@O| or \verb|@D| (instead of \verb|@o| and \verb|@d|).
This doesn't work very well as a default, since far too many short
scraps will be broken across pages; however, as a user-controlled
option, it seems very useful.  No distinction is made between the
upper case and lower case forms of these commands when generating
HTML\@.

\section{Acknowledgements}

Several people have contributed their times, ideas, and debugging
skills. In particular, I'd like to acknowledge the contributions of
Osman Buyukisik, Manuel Carriba, Adrian Clarke, Tim Harvey, Michael
Lewis, Walter Ravenek, Rob Shillingsburg, Kayvan Sylvan, Dominique
de~Waleffe, and Scott Warren.  Of course, most of these people would
never have heard or nuweb (or many other tools) without the efforts of
George Greenwade.


\ifshowcode
\chapter{The Overall Structure}

Processing a web requires three major steps:
\begin{enumerate}
\item Read the source, accumulating file names, macro names, scraps,
and lists of cross-references.
\item Reread the source, copying out to the documentation file, with
protection and cross-reference information for all the scraps.
\item Traverse the list of files names. For each file name:
\begin{enumerate}
\item Dump all the defining scraps into a temporary file. 
\item If the file already exists and is unchanged, delete the
temporary file; otherwise, rename the temporary file.
\end{enumerate}
\end{enumerate}


\section{Files}

I have divided the program into several files for quicker
recompilation during development.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap1}
\verb@"global.h"@ {\footnotesize 7a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@@$\langle$Include files {\footnotesize 7b}$\rangle$\verb@@\\
\mbox{}\verb@@$\langle$Type declarations {\footnotesize 8a, \ldots\ }$\rangle$\verb@@\\
\mbox{}\verb@@$\langle$Global variable declarations {\footnotesize 10a, \ldots\ }$\rangle$\verb@@\\
\mbox{}\verb@@$\langle$Function prototypes {\footnotesize 14a, \ldots\ }$\rangle$\verb@@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-2ex}
\end{minipage}\\[4ex]
\end{flushleft}
We'll need at least three of the standard system include files.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap2}
$\langle$Include files {\footnotesize 7b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include <stdlib.h>@\\
\mbox{}\verb@#include <stdio.h>@\\
\mbox{}\verb@#include <string.h>@\\
\mbox{}\verb@#include <ctype.h>@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\newpage
\noindent
I also like to use \verb|TRUE| and \verb|FALSE| in my code.
I'd use an \verb|enum| here, except that some systems seem to provide
definitions of \verb|TRUE| and \verb|FALSE| be default.  The following
code seems to work on all the local systems.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap3}
$\langle$Type declarations {\footnotesize 8a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#ifndef FALSE@\\
\mbox{}\verb@#define FALSE 0@\\
\mbox{}\verb@#endif@\\
\mbox{}\verb@#ifndef TRUE@\\
\mbox{}\verb@#define TRUE 1@\\
\mbox{}\verb@#endif@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 8a, 52c, 53a.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{The Main Files}

The code is divided into four main files (introduced here) and five
support files (introduced in the next section).
The file \verb|main.c| will contain the driver for the whole program
(see Section~\ref{main-routine}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap4}
\verb@"main.c"@ {\footnotesize 8b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8b, 9f.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The first pass over the source file is contained in \verb|pass1.c|.
It handles collection of all the file names, macros names, and scraps
(see Section~\ref{pass-one}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap5}
\verb@"pass1.c"@ {\footnotesize 8c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8c, 14b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The \verb|.tex| file is created during a second pass over the source
file. The file \verb|latex.c| contains the code controlling the
construction of the \verb|.tex| file 
(see Section~\ref{latex-file}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap6}
\verb@"latex.c"@ {\footnotesize 8d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The file \verb|html.c| contains the code controlling the
construction of the \verb|.tex| file appropriate for use with {\LaTeX}2HTML
(see Section~\ref{html-file}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap7}
\verb@"html.c"@ {\footnotesize 8e }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The code controlling the creation of the output files is in \verb|output.c|
(see Section~\ref{output-files}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap8}
\verb@"output.c"@ {\footnotesize 8f }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8f, 37c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\newpage
\subsection{Support Files}

The support files contain a variety of support routines used to define
and manipulate the major data abstractions.
The file \verb|input.c| holds all the routines used for referring to
source files (see Section~\ref{source-files}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap9}
\verb@"input.c"@ {\footnotesize 9a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9a, 39d, 40ab, 42c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Creation and lookup of scraps is handled by routines in \verb|scraps.c|
(see Section~\ref{scraps}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap10}
\verb@"scraps.c"@ {\footnotesize 9b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The handling of file names and macro names is detailed in \verb|names.c|
(see Section~\ref{names}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap11}
\verb@"names.c"@ {\footnotesize 9c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Memory allocation and deallocation is handled by routines in \verb|arena.c|
(see Section~\ref{memory-management}).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap12}
\verb@"arena.c"@ {\footnotesize 9d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9d, 70abc, 71c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Finally, for best portability, I seem to need a file containing
(useless!) definitions of all the global variables.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap13}
\verb@"global.c"@ {\footnotesize 9e }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#include "global.h"@\\
\mbox{}\verb@@$\langle$Global variable definitions {\footnotesize 10b, \ldots\ }$\rangle$\verb@@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-2ex}
\end{minipage}\\[4ex]
\end{flushleft}
\section{The Main Routine} \label{main-routine}

The main routine is quite simple in structure.
It wades through the optional command-line arguments,
then handles any files listed on the command line.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap14}
\verb@"main.c"@ {\footnotesize 9f }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int main(argc, argv)@\\
\mbox{}\verb@     int argc;@\\
\mbox{}\verb@     char **argv;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int arg = 1;@\\
\mbox{}\verb@  @$\langle$Interpret command-line arguments {\footnotesize 10e, \ldots\ }$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Process the remaining arguments (file names) {\footnotesize 11c}$\rangle$\verb@@\\
\mbox{}\verb@  exit(0);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8b, 9f.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Command-Line Arguments}

There are five possible command-line arguments:
\begin{description}
\item[\tt -t] Suppresses generation of the {\tt .tex} file.
\item[\tt -o] Suppresses generation of the output files.
\item[\tt -c] Forces output files to overwrite old files of the same
  name without comparing for equality first.
\item[\tt -v] The verbose flag. Forces output of progress reports.
\item[\tt -n] Forces sequential numbering of scraps (instead of page
  numbers).
\end{description}

\noindent
Global flags are declared for each of the arguments.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap15}
$\langle$Global variable declarations {\footnotesize 10a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern int tex_flag;      /* if FALSE, don't emit the documentation file */@\\
\mbox{}\verb@extern int html_flag;     /* if TRUE, emit HTML instead of LaTeX scraps. */@\\
\mbox{}\verb@extern int output_flag;   /* if FALSE, don't emit the output files */@\\
\mbox{}\verb@extern int compare_flag;  /* if FALSE, overwrite without comparison */@\\
\mbox{}\verb@extern int verbose_flag;  /* if TRUE, write progress information */@\\
\mbox{}\verb@extern int number_flag;   /* if TRUE, use a sequential numbering scheme */@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10ac, 39b, 44d, 53b.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The flags are all initialized for correct default behavior.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap16}
$\langle$Global variable definitions {\footnotesize 10b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int tex_flag = TRUE;@\\
\mbox{}\verb@int html_flag = FALSE;@\\
\mbox{}\verb@int output_flag = TRUE;@\\
\mbox{}\verb@int compare_flag = TRUE;@\\
\mbox{}\verb@int verbose_flag = FALSE;@\\
\mbox{}\verb@int number_flag = FALSE;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10bd, 39c, 45a, 53c.
\item Macro referenced in scrap 9e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We save the invocation name of the command in a global variable
\verb|command_name| for use in error messages.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap17}
$\langle$Global variable declarations {\footnotesize 10c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern char *command_name;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10ac, 39b, 44d, 53b.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap18}
$\langle$Global variable definitions {\footnotesize 10d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@char *command_name = NULL;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10bd, 39c, 45a, 53c.
\item Macro referenced in scrap 9e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The invocation name is conventionally passed in \verb|argv[0]|.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap19}
$\langle$Interpret command-line arguments {\footnotesize 10e}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@command_name = argv[0];@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10e, 11a.
\item Macro referenced in scrap 9f.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We need to examine the remaining entries in \verb|argv|, looking for
command-line arguments.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap20}
$\langle$Interpret command-line arguments {\footnotesize 11a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@while (arg < argc) {@\\
\mbox{}\verb@  char *s = argv[arg];@\\
\mbox{}\verb@  if (*s++ == '-') {@\\
\mbox{}\verb@    @$\langle$Interpret the argument string \verb|s| {\footnotesize 11b}$\rangle$\verb@@\\
\mbox{}\verb@    arg++;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else break;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10e, 11a.
\item Macro referenced in scrap 9f.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Several flags can be stacked behind a single minus sign; therefore,
we've got to loop through the string, handling them all.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap21}
$\langle$Interpret the argument string \verb|s| {\footnotesize 11b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char c = *s++;@\\
\mbox{}\verb@  while (c) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case 'c': compare_flag = FALSE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case 'n': number_flag = TRUE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case 'o': output_flag = FALSE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case 't': tex_flag = FALSE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case 'v': verbose_flag = TRUE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      default:  fprintf(stderr, "%s: unexpected argument ignored.  ",@\\
\mbox{}\verb@                        command_name);@\\
\mbox{}\verb@                fprintf(stderr, "Usage is: %s [-cnotv] file...\n",@\\
\mbox{}\verb@                        command_name);@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    c = *s++;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 11a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{File Names}

We expect at least one file name. While a missing file name might be
ignored without causing any problems, we take the opportunity to report
the usage convention.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap22}
$\langle$Process the remaining arguments (file names) {\footnotesize 11c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (arg >= argc) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: expected a file name.  ", command_name);@\\
\mbox{}\verb@    fprintf(stderr, "Usage is: %s [-cnotv] file-name...\n", command_name);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  do {@\\
\mbox{}\verb@    @$\langle$Handle the file name in \verb|argv[arg]| {\footnotesize 12a}$\rangle$\verb@@\\
\mbox{}\verb@    arg++;@\\
\mbox{}\verb@  } while (arg < argc);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 9f.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\newpage
\noindent
The code to handle a particular file name is rather more tedious than
the actual processing of the file. A file name may be an arbitrarily
complicated path name, with an optional extension. If no extension is
present, we add \verb|.w| as a default. The extended path name will be
kept in a local variable \verb|source_name|. The resulting documentation
file will be written in the current directory; its name will be kept
in the variable \verb|tex_name|.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap23}
$\langle$Handle the file name in \verb|argv[arg]| {\footnotesize 12a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char source_name[100];@\\
\mbox{}\verb@  char tex_name[100];@\\
\mbox{}\verb@  char aux_name[100];@\\
\mbox{}\verb@  @$\langle$Build \verb|source_name| and \verb|tex_name| {\footnotesize 12b}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Process a file {\footnotesize 13}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 11c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
I bump the pointer \verb|p| through all the characters in \verb|argv[arg]|,
copying all the characters into \verb|source_name| (via the pointer
\verb|q|). 

At each slash, I update \verb|trim| to point just past the
slash in \verb|source_name|. The effect is that \verb|trim| will point
at the file name without any leading directory specifications.

The pointer \verb|dot| is made to point at the file name extension, if
present. If there is no extension, we add \verb|.w| to the source name.
In any case, we create the \verb|tex_name| from \verb|trim|, taking
care to get the correct extension.  The \verb|html_flag| is set in
this scrap.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap24}
$\langle$Build \verb|source_name| and \verb|tex_name| {\footnotesize 12b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char *p = argv[arg];@\\
\mbox{}\verb@  char *q = source_name;@\\
\mbox{}\verb@  char *trim = q;@\\
\mbox{}\verb@  char *dot = NULL;@\\
\mbox{}\verb@  char c = *p++;@\\
\mbox{}\verb@  while (c) {@\\
\mbox{}\verb@    *q++ = c;@\\
\mbox{}\verb@    if (c == '/') {@\\
\mbox{}\verb@      trim = q;@\\
\mbox{}\verb@      dot = NULL;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else if (c == '.')@\\
\mbox{}\verb@      dot = q - 1;@\\
\mbox{}\verb@    c = *p++;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  *q = '\0';@\\
\mbox{}\verb@  if (dot) {@\\
\mbox{}\verb@    *dot = '\0'; /* produce HTML when the file extension is ".hw" */@\\
\mbox{}\verb@    html_flag = dot[1] == 'h' && dot[2] == 'w' && dot[3] == '\0';@\\
\mbox{}\verb@    sprintf(tex_name, "%s.tex", trim);@\\
\mbox{}\verb@    sprintf(aux_name, "%s.aux", trim);@\\
\mbox{}\verb@    *dot = '.';@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    sprintf(tex_name, "%s.tex", trim);@\\
\mbox{}\verb@    sprintf(aux_name, "%s.aux", trim);@\\
\mbox{}\verb@    *q++ = '.';@\\
\mbox{}\verb@    *q++ = 'w';@\\
\mbox{}\verb@    *q = '\0';@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 12a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Now that we're finally ready to process a file, it's not really too
complex.  We bundle most of the work into four routines \verb|pass1|
(see Section~\ref{pass-one}), \verb|write_tex| (see
Section~\ref{latex-file}), \verb|write_html| (see
Section~\ref{html-file}), and \verb|write_files| (see
Section~\ref{output-files}). After we're finished with a
particular file, we must remember to release its storage (see
Section~\ref{memory-management}).  The sequential numbering of scraps
is forced when generating HTML.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap25}
$\langle$Process a file {\footnotesize 13}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  pass1(source_name);@\\
\mbox{}\verb@  if (tex_flag) {@\\
\mbox{}\verb@    if (html_flag) {@\\
\mbox{}\verb@      int saved_number_flag = number_flag; @\\
\mbox{}\verb@      number_flag = TRUE;@\\
\mbox{}\verb@      collect_numbers(aux_name);@\\
\mbox{}\verb@      write_html(source_name, tex_name);@\\
\mbox{}\verb@      number_flag = saved_number_flag;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      collect_numbers(aux_name);@\\
\mbox{}\verb@      write_tex(source_name, tex_name);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (output_flag)@\\
\mbox{}\verb@    write_files(file_names);@\\
\mbox{}\verb@  arena_free();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 12a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\newpage
\section{Pass One} \label{pass-one}

During the first pass, we scan the file, recording the definitions of
each macro and file and accumulating all the scraps. 

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap26}
$\langle$Function prototypes {\footnotesize 14a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void pass1();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The routine \verb|pass1| takes a single argument, the name of the
source file. It opens the file, then initializes the scrap structures
(see Section~\ref{scraps}) and the roots of the file-name tree, the
macro-name tree, and the tree of user-specified index entries (see 
Section~\ref{names}). After completing all the
necessary preparation, we make a pass over the file, filling in all
our data structures. Next, we seach all the scraps for references to
the user-specified index entries. Finally, we must reverse all the
cross-reference lists accumulated while scanning the scraps.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap27}
\verb@"pass1.c"@ {\footnotesize 14b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void pass1(file_name)@\\
\mbox{}\verb@     char *file_name;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  if (verbose_flag)@\\
\mbox{}\verb@    fprintf(stderr, "reading %s\n", file_name);@\\
\mbox{}\verb@  source_open(file_name);@\\
\mbox{}\verb@  init_scraps();@\\
\mbox{}\verb@  macro_names = NULL;@\\
\mbox{}\verb@  file_names = NULL;@\\
\mbox{}\verb@  user_names = NULL;@\\
\mbox{}\verb@  @$\langle$Scan the source file, looking for at-sequences {\footnotesize 14c}$\rangle$\verb@@\\
\mbox{}\verb@  if (tex_flag)@\\
\mbox{}\verb@    search();@\\
\mbox{}\verb@  @$\langle$Reverse cross-reference lists {\footnotesize 16b}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8c, 14b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The only thing we look for in the first pass are the command
sequences. All ordinary text is skipped entirely.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap28}
$\langle$Scan the source file, looking for at-sequences {\footnotesize 14c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (c != EOF) {@\\
\mbox{}\verb@    if (c == '@{\tt @}\verb@')@\\
\mbox{}\verb@      @$\langle$Scan at-sequence {\footnotesize 15a}$\rangle$\verb@@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 14b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Only four of the at-sequences are interesting during the first pass.
We skip past others immediately; warning if unexpected sequences are
discovered.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap29}
$\langle$Scan at-sequence {\footnotesize 15a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case 'O':@\\
\mbox{}\verb@    case 'o': @$\langle$Build output file definition {\footnotesize 15b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'D':@\\
\mbox{}\verb@    case 'd': @$\langle$Build macro definition {\footnotesize 15c}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '@{\tt @}\verb@':@\\
\mbox{}\verb@    case 'u':@\\
\mbox{}\verb@    case 'm':@\\
\mbox{}\verb@    case 'f': /* ignore during this pass */@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    default:  fprintf(stderr,@\\
\mbox{}\verb@                      "%s: unexpected @{\tt @}\verb@ sequence ignored (%s, line %d)\n",@\\
\mbox{}\verb@                      command_name, source_name, source_line);@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 14c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Accumulating Definitions}

There are three steps required to handle a definition:
\begin{enumerate}
\item Build an entry for the name so we can look it up later.
\item Collect the scrap and save it in the table of scraps.
\item Attach the scrap to the name.
\end{enumerate}
We go through the same steps for both file names and macro names.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap30}
$\langle$Build output file definition {\footnotesize 15b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_file_name(); /* returns a pointer to the name entry */@\\
\mbox{}\verb@  int scrap = collect_scrap();      /* returns an index to the scrap */@\\
\mbox{}\verb@  @$\langle$Add \verb|scrap| to \verb|name|'s definition list {\footnotesize 16a}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 15a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap31}
$\langle$Build macro definition {\footnotesize 15c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_macro_name();@\\
\mbox{}\verb@  int scrap = collect_scrap();@\\
\mbox{}\verb@  @$\langle$Add \verb|scrap| to \verb|name|'s definition list {\footnotesize 16a}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 15a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Since a file or macro may be defined by many scraps, we maintain them
in a simple linked list. The list is actually built in reverse order,
with each new definition being added to the head of the list.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap32}
$\langle$Add \verb|scrap| to \verb|name|'s definition list {\footnotesize 16a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *def = (Scrap_Node *) arena_getmem(sizeof(Scrap_Node));@\\
\mbox{}\verb@  def->scrap = scrap;@\\
\mbox{}\verb@  def->next = name->defs;@\\
\mbox{}\verb@  name->defs = def;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 15bc.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Fixing the Cross References}

Since the definition and reference lists for each name are accumulated
in reverse order, we take the time at the end of \verb|pass1| to
reverse them all so they'll be simpler to print out prettily.
The code for \verb|reverse_lists| appears in Section~\ref{names}.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap33}
$\langle$Reverse cross-reference lists {\footnotesize 16b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  reverse_lists(file_names);@\\
\mbox{}\verb@  reverse_lists(macro_names);@\\
\mbox{}\verb@  reverse_lists(user_names);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 14b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Writing the Latex File} \label{latex-file}

The second pass (invoked via a call to \verb|write_tex|) copies most of
the text from the source file straight into a \verb|.tex| file.
Definitions are formatted slightly and cross-reference information is
printed out.

Note that all the formatting is handled in this section.
If you don't like the format of definitions or indices or whatever,
it'll be in this section somewhere. Similarly, if someone wanted to
modify nuweb to work with a different typesetting system, this would
be the place to look.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap34}
$\langle$Function prototypes {\footnotesize 16c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void write_tex();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We need a few local function declarations before we get into the body
of \verb|write_tex|.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap35}
\verb@"latex.c"@ {\footnotesize 16d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void copy_scrap();               /* formats the body of a scrap */@\\
\mbox{}\verb@static void print_scrap_numbers();      /* formats a list of scrap numbers */@\\
\mbox{}\verb@static void format_entry();             /* formats an index entry */@\\
\mbox{}\verb@static void format_user_entry();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The routine \verb|write_tex| takes two file names as parameters: the
name of the web source file and the name of the \verb|.tex| output file.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap36}
\verb@"latex.c"@ {\footnotesize 17a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void write_tex(file_name, tex_name)@\\
\mbox{}\verb@     char *file_name;@\\
\mbox{}\verb@     char *tex_name;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  FILE *tex_file = fopen(tex_name, "w");@\\
\mbox{}\verb@  if (tex_file) {@\\
\mbox{}\verb@    if (verbose_flag)@\\
\mbox{}\verb@      fprintf(stderr, "writing %s\n", tex_name);@\\
\mbox{}\verb@    source_open(file_name);@\\
\mbox{}\verb@    @$\langle$Copy \verb|source_file| into \verb|tex_file| {\footnotesize 17b}$\rangle$\verb@@\\
\mbox{}\verb@    fclose(tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    fprintf(stderr, "%s: can't open %s\n", command_name, tex_name);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We make our second (and final) pass through the source web, this time
copying characters straight into the \verb|.tex| file. However, we keep
an eye peeled for \verb|@|~characters, which signal a command sequence.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap37}
$\langle$Copy \verb|source_file| into \verb|tex_file| {\footnotesize 17b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int scraps = 1;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (c != EOF) {@\\
\mbox{}\verb@    if (c == '@{\tt @}\verb@')@\\
\mbox{}\verb@      @$\langle$Interpret at-sequence {\footnotesize 18}$\rangle$\verb@@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      putc(c, tex_file);@\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 17a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap38}
$\langle$Interpret at-sequence {\footnotesize 18}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int big_definition = FALSE;@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case 'O': big_definition = TRUE;@\\
\mbox{}\verb@    case 'o': @$\langle$Write output file definition {\footnotesize 19a}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'D': big_definition = TRUE;@\\
\mbox{}\verb@    case 'd': @$\langle$Write macro definition {\footnotesize 19b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'f': @$\langle$Write index of file names {\footnotesize 23d}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'm': @$\langle$Write index of macro names {\footnotesize 24a}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'u': @$\langle$Write index of user-specified names {\footnotesize 26a}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '@{\tt @}\verb@': putc(c, tex_file);@\\
\mbox{}\verb@    default:  c = source_get();@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 17b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Formatting Definitions}

We go through a fair amount of effort to format a file definition.
I've derived most of the \LaTeX\ commands experimentally; it's quite
likely that an expert could do a better job. The \LaTeX\ for
the previous macro definition should look like this (perhaps modulo
the scrap references):
{\small
\begin{verbatim}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap37}
$\langle$Interpret at-sequence {\footnotesize 18}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int big_definition = FALSE;@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case 'O': big_definition = TRUE;@\\
\mbox{}\verb@    case 'o': @$\langle$Write output file definition {\footnotesize 19a}$\rangle$\verb@@\\
\end{verbatim}
\vdots
\begin{verbatim}
\mbox{}\verb@    case '@{\tt @}\verb@': putc(c, tex_file);@\\
\mbox{}\verb@    default:  c = source_get();@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 17b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\end{verbatim}}

\noindent
The {\em flushleft\/} environment is used to avoid \LaTeX\ warnings
about underful lines. The {\em minipage\/} environment is used to
avoid page breaks in the middle of scraps. The {\em verb\/} command
allows arbitrary characters to be printed (however, note the special
handling of the \verb|@| case in the switch statement).

Macro and file definitions are formatted nearly identically.
I've factored the common parts out into separate scraps.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap39}
$\langle$Write output file definition {\footnotesize 19a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_file_name();@\\
\mbox{}\verb@  @$\langle$Begin the scrap environment {\footnotesize 19c}$\rangle$\verb@@\\
\mbox{}\verb@  fprintf(tex_file, "\\verb@{\tt @}\verb@\"%s\"@{\tt @}\verb@ {\\footnotesize ", name->spelling);@\\
\mbox{}\verb@  write_single_scrap_ref(tex_file, scraps++);@\\
\mbox{}\verb@  fputs(" }$\\equiv$\n", tex_file);@\\
\mbox{}\verb@  @$\langle$Fill in the middle of the scrap environment {\footnotesize 19d}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write file defs {\footnotesize 20b}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Finish the scrap environment {\footnotesize 20a}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 18.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
I don't format a macro name at all specially, figuring the programmer
might want to use italics or bold face in the midst of the name.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap40}
$\langle$Write macro definition {\footnotesize 19b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_macro_name();@\\
\mbox{}\verb@  @$\langle$Begin the scrap environment {\footnotesize 19c}$\rangle$\verb@@\\
\mbox{}\verb@  fprintf(tex_file, "$\\langle$%s {\\footnotesize ", name->spelling);@\\
\mbox{}\verb@  write_single_scrap_ref(tex_file, scraps++);@\\
\mbox{}\verb@  fputs("}$\\rangle\\equiv$\n", tex_file);@\\
\mbox{}\verb@  @$\langle$Fill in the middle of the scrap environment {\footnotesize 19d}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write macro defs {\footnotesize 20c}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write macro refs {\footnotesize 21a}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Finish the scrap environment {\footnotesize 20a}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 18.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap41}
$\langle$Begin the scrap environment {\footnotesize 19c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\begin{flushleft} \\small", tex_file);@\\
\mbox{}\verb@  if (!big_definition)@\\
\mbox{}\verb@    fputs("\n\\begin{minipage}{\\linewidth}", tex_file);@\\
\mbox{}\verb@  fprintf(tex_file, " \\label{scrap%d}\n", scraps);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 19ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The interesting things here are the $\Diamond$ inserted at the end of
each scrap and the various spacing commands. The diamond helps to
clearly indicate the end of a scrap. The spacing commands were derived
empirically; they may be adjusted to taste.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap42}
$\langle$Fill in the middle of the scrap environment {\footnotesize 19d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\vspace{-1ex}\n\\begin{list}{}{} \\item\n", tex_file);@\\
\mbox{}\verb@  copy_scrap(tex_file);@\\
\mbox{}\verb@  fputs("$\\Diamond$\n\\end{list}\n", tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 19ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\newpage
\noindent
We've got one last spacing command, controlling the amount of white
space after a scrap.

Note also the whitespace eater. I use it to remove any blank lines
that appear after a scrap in the source file. This way, text following
a scrap will not be indented. Again, this is a matter of personal taste.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap43}
$\langle$Finish the scrap environment {\footnotesize 20a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (!big_definition)@\\
\mbox{}\verb@    fputs("\\end{minipage}\\\\[4ex]\n", tex_file);@\\
\mbox{}\verb@  fputs("\\end{flushleft}\n", tex_file);@\\
\mbox{}\verb@  do@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  while (isspace(c));@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 19ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsubsection{Formatting Cross References}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap44}
$\langle$Write file defs {\footnotesize 20b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->defs->next) {@\\
\mbox{}\verb@    fputs("\\vspace{-1ex}\n", tex_file);@\\
\mbox{}\verb@    fputs("\\footnotesize\\addtolength{\\baselineskip}{-1ex}\n", tex_file);@\\
\mbox{}\verb@    fputs("\\begin{list}{}{\\setlength{\\itemsep}{-\\parsep}", tex_file);@\\
\mbox{}\verb@    fputs("\\setlength{\\itemindent}{-\\leftmargin}}\n", tex_file);@\\
\mbox{}\verb@    fputs("\\item File defined by scraps ", tex_file);@\\
\mbox{}\verb@    print_scrap_numbers(tex_file, name->defs);@\\
\mbox{}\verb@    fputs("\\end{list}\n", tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    fputs("\\vspace{-2ex}\n", tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 19a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap45}
$\langle$Write macro defs {\footnotesize 20c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\vspace{-1ex}\n", tex_file);@\\
\mbox{}\verb@  fputs("\\footnotesize\\addtolength{\\baselineskip}{-1ex}\n", tex_file);@\\
\mbox{}\verb@  fputs("\\begin{list}{}{\\setlength{\\itemsep}{-\\parsep}", tex_file);@\\
\mbox{}\verb@  fputs("\\setlength{\\itemindent}{-\\leftmargin}}\n", tex_file);@\\
\mbox{}\verb@  if (name->defs->next) {@\\
\mbox{}\verb@    fputs("\\item Macro defined by scraps ", tex_file);@\\
\mbox{}\verb@    print_scrap_numbers(tex_file, name->defs);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 19b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap46}
$\langle$Write macro refs {\footnotesize 21a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->uses) {@\\
\mbox{}\verb@    if (name->uses->next) {@\\
\mbox{}\verb@      fputs("\\item Macro referenced in scraps ", tex_file);@\\
\mbox{}\verb@      print_scrap_numbers(tex_file, name->uses);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      fputs("\\item Macro referenced in scrap ", tex_file);@\\
\mbox{}\verb@      write_single_scrap_ref(tex_file, name->uses->scrap);@\\
\mbox{}\verb@      fputs(".\n", tex_file);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    fputs("\\item Macro never referenced.\n", tex_file);@\\
\mbox{}\verb@    fprintf(stderr, "%s: <%s> never referenced.\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fputs("\\end{list}\n", tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 19b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap47}
\verb@"latex.c"@ {\footnotesize 21b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void print_scrap_numbers(tex_file, scraps)@\\
\mbox{}\verb@     FILE *tex_file;@\\
\mbox{}\verb@     Scrap_Node *scraps;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int page;@\\
\mbox{}\verb@  write_scrap_ref(tex_file, scraps->scrap, TRUE, &page);@\\
\mbox{}\verb@  scraps = scraps->next;@\\
\mbox{}\verb@  while (scraps) {@\\
\mbox{}\verb@    write_scrap_ref(tex_file, scraps->scrap, FALSE, &page);@\\
\mbox{}\verb@    scraps = scraps->next;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fputs(".\n", tex_file);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsubsection{Formatting a Scrap}

We add a \verb|\mbox{}| at the beginning of each line to avoid
problems with older versions of \TeX.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap48}
\verb@"latex.c"@ {\footnotesize 22a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void copy_scrap(file)@\\
\mbox{}\verb@     FILE *file;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int indent = 0;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  fputs("\\mbox{}\\verb@{\tt @}\verb@", file);@\\
\mbox{}\verb@  while (1) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case '@{\tt @}\verb@':  @$\langle$Check at-sequence for end-of-scrap {\footnotesize 22c}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\n': fputs("@{\tt @}\verb@\\\\\n\\mbox{}\\verb@{\tt @}\verb@", file);@\\
\mbox{}\verb@                 indent = 0;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\t': @$\langle$Expand tab into spaces {\footnotesize 22b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      default:   putc(c, file);@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap49}
$\langle$Expand tab into spaces {\footnotesize 22b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int delta = 8 - (indent % 8);@\\
\mbox{}\verb@  indent += delta;@\\
\mbox{}\verb@  while (delta > 0) {@\\
\mbox{}\verb@    putc(' ', file);@\\
\mbox{}\verb@    delta--;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 22a, 33a, 51a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap50}
$\langle$Check at-sequence for end-of-scrap {\footnotesize 22c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': fputs("@{\tt @}\verb@{\\tt @{\tt @}\verb@}\\verb@{\tt @}\verb@", file);@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '|': @$\langle$Skip over index entries {\footnotesize 23a}$\rangle$\verb@@\\
\mbox{}\verb@    case '}': putc('@{\tt @}\verb@', file);@\\
\mbox{}\verb@              return;@\\
\mbox{}\verb@    case '<': @$\langle$Format macro name {\footnotesize 23b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    default:  /* ignore these since pass1 will have warned about them */@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 22a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
There's no need to check for errors here, since we will have already
pointed out any during the first pass.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap51}
$\langle$Skip over index entries {\footnotesize 23a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  do {@\\
\mbox{}\verb@    do@\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@    while (c != '@{\tt @}\verb@');@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  } while (c != '}');@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 22c, 33b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap52}
$\langle$Format macro name {\footnotesize 23b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_scrap_name();@\\
\mbox{}\verb@  fprintf(file, "@{\tt @}\verb@$\\langle$%s {\\footnotesize ", name->spelling);@\\
\mbox{}\verb@  if (name->defs)@\\
\mbox{}\verb@    @$\langle$Write abbreviated definition list {\footnotesize 23c}$\rangle$\verb@@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    putc('?', file);@\\
\mbox{}\verb@    fprintf(stderr, "%s: scrap never defined <%s>\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fputs("}$\\rangle$\\verb@{\tt @}\verb@", file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 22c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap53}
$\langle$Write abbreviated definition list {\footnotesize 23c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->defs;@\\
\mbox{}\verb@  write_single_scrap_ref(file, p->scrap);@\\
\mbox{}\verb@  p = p->next;@\\
\mbox{}\verb@  if (p)@\\
\mbox{}\verb@    fputs(", \\ldots\\ ", file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 23b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Generating the Indices}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap54}
$\langle$Write index of file names {\footnotesize 23d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (file_names) {@\\
\mbox{}\verb@    fputs("\n{\\small\\begin{list}{}{\\setlength{\\itemsep}{-\\parsep}",@\\
\mbox{}\verb@          tex_file);@\\
\mbox{}\verb@    fputs("\\setlength{\\itemindent}{-\\leftmargin}}\n", tex_file);@\\
\mbox{}\verb@    format_entry(file_names, tex_file, TRUE);@\\
\mbox{}\verb@    fputs("\\end{list}}", tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 18.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap55}
$\langle$Write index of macro names {\footnotesize 24a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (macro_names) {@\\
\mbox{}\verb@    fputs("\n{\\small\\begin{list}{}{\\setlength{\\itemsep}{-\\parsep}",@\\
\mbox{}\verb@          tex_file);@\\
\mbox{}\verb@    fputs("\\setlength{\\itemindent}{-\\leftmargin}}\n", tex_file);@\\
\mbox{}\verb@    format_entry(macro_names, tex_file, FALSE);@\\
\mbox{}\verb@    fputs("\\end{list}}", tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 18.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap56}
\verb@"latex.c"@ {\footnotesize 24b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void format_entry(name, tex_file, file_flag)@\\
\mbox{}\verb@     Name *name;@\\
\mbox{}\verb@     FILE *tex_file;@\\
\mbox{}\verb@     int file_flag;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (name) {@\\
\mbox{}\verb@    format_entry(name->llink, tex_file, file_flag);@\\
\mbox{}\verb@    @$\langle$Format an index entry {\footnotesize 24c}$\rangle$\verb@@\\
\mbox{}\verb@    name = name->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap57}
$\langle$Format an index entry {\footnotesize 24c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\item ", tex_file);@\\
\mbox{}\verb@  if (file_flag) {@\\
\mbox{}\verb@    fprintf(tex_file, "\\verb@{\tt @}\verb@\"%s\"@{\tt @}\verb@ ", name->spelling);@\\
\mbox{}\verb@    @$\langle$Write file's defining scrap numbers {\footnotesize 25a}$\rangle$\verb@@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    fprintf(tex_file, "$\\langle$%s {\\footnotesize ", name->spelling);@\\
\mbox{}\verb@    @$\langle$Write defining scrap numbers {\footnotesize 25b}$\rangle$\verb@@\\
\mbox{}\verb@    fputs("}$\\rangle$ ", tex_file);@\\
\mbox{}\verb@    @$\langle$Write referencing scrap numbers {\footnotesize 25c}$\rangle$\verb@@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  putc('\n', tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 24b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap58}
$\langle$Write file's defining scrap numbers {\footnotesize 25a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->defs;@\\
\mbox{}\verb@  fputs("{\\footnotesize Defined by scrap", tex_file);@\\
\mbox{}\verb@  if (p->next) {@\\
\mbox{}\verb@    fputs("s ", tex_file);@\\
\mbox{}\verb@    print_scrap_numbers(tex_file, p);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    putc(' ', tex_file);@\\
\mbox{}\verb@    write_single_scrap_ref(tex_file, p->scrap);@\\
\mbox{}\verb@    putc('.', tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  putc('}', tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 24c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap59}
$\langle$Write defining scrap numbers {\footnotesize 25b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->defs;@\\
\mbox{}\verb@  if (p) {@\\
\mbox{}\verb@    int page;@\\
\mbox{}\verb@    write_scrap_ref(tex_file, p->scrap, TRUE, &page);@\\
\mbox{}\verb@    p = p->next;@\\
\mbox{}\verb@    while (p) {@\\
\mbox{}\verb@      write_scrap_ref(tex_file, p->scrap, FALSE, &page);@\\
\mbox{}\verb@      p = p->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    putc('?', tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 24c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap60}
$\langle$Write referencing scrap numbers {\footnotesize 25c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->uses;@\\
\mbox{}\verb@  fputs("{\\footnotesize ", tex_file);@\\
\mbox{}\verb@  if (p) {@\\
\mbox{}\verb@    fputs("Referenced in scrap", tex_file);@\\
\mbox{}\verb@    if (p->next) {@\\
\mbox{}\verb@      fputs("s ", tex_file);@\\
\mbox{}\verb@      print_scrap_numbers(tex_file, p);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      putc(' ', tex_file);@\\
\mbox{}\verb@      write_single_scrap_ref(tex_file, p->scrap);@\\
\mbox{}\verb@      putc('.', tex_file);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    fputs("Not referenced.", tex_file);@\\
\mbox{}\verb@  putc('}', tex_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 24c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap61}
$\langle$Write index of user-specified names {\footnotesize 26a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (user_names) {@\\
\mbox{}\verb@    fputs("\n{\\small\\begin{list}{}{\\setlength{\\itemsep}{-\\parsep}",@\\
\mbox{}\verb@          tex_file);@\\
\mbox{}\verb@    fputs("\\setlength{\\itemindent}{-\\leftmargin}}\n", tex_file);@\\
\mbox{}\verb@    format_user_entry(user_names, tex_file);@\\
\mbox{}\verb@    fputs("\\end{list}}", tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 18.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap62}
\verb@"latex.c"@ {\footnotesize 26b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void format_user_entry(name, tex_file)@\\
\mbox{}\verb@     Name *name;@\\
\mbox{}\verb@     FILE *tex_file;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (name) {@\\
\mbox{}\verb@    format_user_entry(name->llink, tex_file);@\\
\mbox{}\verb@    @$\langle$Format a user index entry {\footnotesize 27a}$\rangle$\verb@@\\
\mbox{}\verb@    name = name->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap63}
$\langle$Format a user index entry {\footnotesize 27a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *uses = name->uses;@\\
\mbox{}\verb@  if (uses) {@\\
\mbox{}\verb@    int page;@\\
\mbox{}\verb@    Scrap_Node *defs = name->defs;@\\
\mbox{}\verb@    fprintf(tex_file, "\\item \\verb@{\tt @}\verb@%s@{\tt @}\verb@: ", name->spelling);@\\
\mbox{}\verb@    if (uses->scrap < defs->scrap) {@\\
\mbox{}\verb@      write_scrap_ref(tex_file, uses->scrap, TRUE, &page);@\\
\mbox{}\verb@      uses = uses->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      if (defs->scrap == uses->scrap)@\\
\mbox{}\verb@        uses = uses->next;@\\
\mbox{}\verb@      fputs("\\underline{", tex_file);@\\
\mbox{}\verb@      write_single_scrap_ref(tex_file, defs->scrap);@\\
\mbox{}\verb@      putc('}', tex_file);@\\
\mbox{}\verb@      page = -2;@\\
\mbox{}\verb@      defs = defs->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    while (uses || defs) {@\\
\mbox{}\verb@      if (uses && (!defs || uses->scrap < defs->scrap)) {@\\
\mbox{}\verb@        write_scrap_ref(tex_file, uses->scrap, FALSE, &page);@\\
\mbox{}\verb@        uses = uses->next;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@      else {@\\
\mbox{}\verb@        if (uses && defs->scrap == uses->scrap)@\\
\mbox{}\verb@          uses = uses->next;@\\
\mbox{}\verb@        fputs(", \\underline{", tex_file);@\\
\mbox{}\verb@        write_single_scrap_ref(tex_file, defs->scrap);@\\
\mbox{}\verb@        putc('}', tex_file);@\\
\mbox{}\verb@        page = -2;@\\
\mbox{}\verb@        defs = defs->next;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    fputs(".\n", tex_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 26b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Writing the LaTeX File with HTML Scraps} \label{html-file} 

The HTML generated is patterned closely upon the {\LaTeX} generated in
the previous section.\footnote{\relax While writing this section, I
tried to follow Preston's style as displayed in
Section~\ref{latex-file}---J. D. R.}  When a file name ends in
\verb|.hw|, the second pass (invoked via a call to \verb|write_html|)
copies most of the text from the source file straight into a
\verb|.tex| file.  Definitions are formatted slightly and
cross-reference information is printed out.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap64}
$\langle$Function prototypes {\footnotesize 27b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void write_html();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We need a few local function declarations before we get into the body
of \verb|write_html|.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap65}
\verb@"html.c"@ {\footnotesize 28a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void copy_scrap();               /* formats the body of a scrap */@\\
\mbox{}\verb@static void display_scrap_ref();        /* formats a scrap reference */@\\
\mbox{}\verb@static void display_scrap_numbers();    /* formats a list of scrap numbers */@\\
\mbox{}\verb@static void print_scrap_numbers();      /* pluralizes scrap formats list */@\\
\mbox{}\verb@static void format_entry();             /* formats an index entry */@\\
\mbox{}\verb@static void format_user_entry();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The routine \verb|write_html| takes two file names as parameters: the
name of the web source file and the name of the \verb|.tex| output file.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap66}
\verb@"html.c"@ {\footnotesize 28b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void write_html(file_name, html_name)@\\
\mbox{}\verb@     char *file_name;@\\
\mbox{}\verb@     char *html_name;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  FILE *html_file = fopen(html_name, "w");@\\
\mbox{}\verb@  if (html_file) {@\\
\mbox{}\verb@    if (verbose_flag)@\\
\mbox{}\verb@      fprintf(stderr, "writing %s\n", html_name);@\\
\mbox{}\verb@    source_open(file_name);@\\
\mbox{}\verb@    @$\langle$Copy \verb|source_file| into \verb|html_file| {\footnotesize 28c}$\rangle$\verb@@\\
\mbox{}\verb@    fclose(html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    fprintf(stderr, "%s: can't open %s\n", command_name, html_name);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We make our second (and final) pass through the source web, this time
copying characters straight into the \verb|.tex| file. However, we keep
an eye peeled for \verb|@|~characters, which signal a command sequence.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap67}
$\langle$Copy \verb|source_file| into \verb|html_file| {\footnotesize 28c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int scraps = 1;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (c != EOF) {@\\
\mbox{}\verb@    if (c == '@{\tt @}\verb@')@\\
\mbox{}\verb@      @$\langle$Interpret HTML at-sequence {\footnotesize 29}$\rangle$\verb@@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      putc(c, html_file);@\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 28b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap68}
$\langle$Interpret HTML at-sequence {\footnotesize 29}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case 'O': @\\
\mbox{}\verb@    case 'o': @$\langle$Write HTML output file definition {\footnotesize 30a}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'D': @\\
\mbox{}\verb@    case 'd': @$\langle$Write HTML macro definition {\footnotesize 30c}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'f': @$\langle$Write HTML index of file names {\footnotesize 34c}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'm': @$\langle$Write HTML index of macro names {\footnotesize 34d}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case 'u': @$\langle$Write HTML index of user-specified names {\footnotesize 36b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '@{\tt @}\verb@': putc(c, html_file);@\\
\mbox{}\verb@    default:  c = source_get();@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 28c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Formatting Definitions}

We go through only a little amount of effort to format a definition.
The HTML for the previous macro definition should look like this
(perhaps modulo the scrap references):

\begin{verbatim}
<pre>
<a name="nuweb68">&lt;Interpret HTML at-sequence 68&gt;</a> =
{
  c = source_get();
  switch (c) {
    case 'O': 
    case 'o': &lt;Write HTML output file definition <a href="#nuweb69">69</a>&gt;
              break;
    case 'D': 
    case 'd': &lt;Write HTML macro definition <a href="#nuweb71">71</a>&gt;
              break;
    case 'f': &lt;Write HTML index of file names <a href="#nuweb86">86</a>&gt;
              break;
    case 'm': &lt;Write HTML index of macro names <a href="#nuweb87">87</a>&gt;
              break;
    case 'u': &lt;Write HTML index of user-specified names <a href="#nuweb93">93</a>&gt;
              break;
    case '@': putc(c, html_file);
    default:  c = source_get();
              break;
  }
}&lt;&gt;</pre>
Macro referenced in scrap <a href="#nuweb67">67</a>.
<br>
\end{verbatim}

Macro and file definitions are formatted nearly identically.
I've factored the common parts out into separate scraps.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap69}
$\langle$Write HTML output file definition {\footnotesize 30a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_file_name();@\\
\mbox{}\verb@  @$\langle$Begin HTML scrap environment {\footnotesize 30e}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write HTML output file declaration {\footnotesize 30b}$\rangle$\verb@@\\
\mbox{}\verb@  scraps++;@\\
\mbox{}\verb@  @$\langle$Fill in the middle of HTML scrap environment {\footnotesize 31a}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write HTML file defs {\footnotesize 31c}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Finish HTML scrap environment {\footnotesize 31b}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 29.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap70}
$\langle$Write HTML output file declaration {\footnotesize 30b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@  fputs("<a name=\"nuweb", html_file);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, scraps);@\\
\mbox{}\verb@  fprintf(html_file, "\"><code>\"%s\"</code> ", name->spelling);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, scraps);@\\
\mbox{}\verb@  fputs("</a> =\n", html_file);@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 30a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap71}
$\langle$Write HTML macro definition {\footnotesize 30c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_macro_name();@\\
\mbox{}\verb@  @$\langle$Begin HTML scrap environment {\footnotesize 30e}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write HTML macro declaration {\footnotesize 30d}$\rangle$\verb@@\\
\mbox{}\verb@  scraps++;@\\
\mbox{}\verb@  @$\langle$Fill in the middle of HTML scrap environment {\footnotesize 31a}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write HTML macro defs {\footnotesize 31d}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Write HTML macro refs {\footnotesize 31e}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Finish HTML scrap environment {\footnotesize 31b}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 29.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
I don't format a macro name at all specially, figuring the programmer
might want to use italics or bold face in the midst of the name.  Note
that in this implementation, programmers may only use directives in
macro names that are recognized in preformatted text elements (PRE).

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap72}
$\langle$Write HTML macro declaration {\footnotesize 30d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@  fputs("<a name=\"nuweb", html_file);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, scraps);@\\
\mbox{}\verb@  fprintf(html_file, "\">&lt;%s ", name->spelling);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, scraps);@\\
\mbox{}\verb@  fputs("&gt;</a> =\n", html_file);@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 30c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap73}
$\langle$Begin HTML scrap environment {\footnotesize 30e}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\begin{rawhtml}\n", html_file);@\\
\mbox{}\verb@  fputs("<pre>\n", html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 30ac.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The end of a scrap is marked with the characters \verb|<>|.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap74}
$\langle$Fill in the middle of HTML scrap environment {\footnotesize 31a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  copy_scrap(html_file);@\\
\mbox{}\verb@  fputs("&lt;&gt;</pre>\n", html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 30ac.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
The only task remaining is to get rid of the current at command and
end the paragraph.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap75}
$\langle$Finish HTML scrap environment {\footnotesize 31b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("\\end{rawhtml}\n", html_file);@\\
\mbox{}\verb@  c = source_get(); /* Get rid of current at command. */@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 30ac.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsubsection{Formatting Cross References}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap76}
$\langle$Write HTML file defs {\footnotesize 31c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->defs->next) {@\\
\mbox{}\verb@    fputs("File defined by ", html_file);@\\
\mbox{}\verb@    print_scrap_numbers(html_file, name->defs);@\\
\mbox{}\verb@    fputs("<br>\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 30a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap77}
$\langle$Write HTML macro defs {\footnotesize 31d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->defs->next) {@\\
\mbox{}\verb@    fputs("Macro defined by ", html_file);@\\
\mbox{}\verb@    print_scrap_numbers(html_file, name->defs);@\\
\mbox{}\verb@    fputs("<br>\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 30c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap78}
$\langle$Write HTML macro refs {\footnotesize 31e}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->uses) {@\\
\mbox{}\verb@    fputs("Macro referenced in ", html_file);@\\
\mbox{}\verb@    print_scrap_numbers(html_file, name->uses);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    fputs("Macro never referenced.\n", html_file);@\\
\mbox{}\verb@    fprintf(stderr, "%s: <%s> never referenced.\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fputs("<br>\n", html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 30c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap79}
\verb@"html.c"@ {\footnotesize 32a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void display_scrap_ref(html_file, num)@\\
\mbox{}\verb@     FILE *html_file;@\\
\mbox{}\verb@     int num;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("<a href=\"#nuweb", html_file);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, num);@\\
\mbox{}\verb@  fputs("\">", html_file);@\\
\mbox{}\verb@  write_single_scrap_ref(html_file, num);@\\
\mbox{}\verb@  fputs("</a>", html_file);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap80}
\verb@"html.c"@ {\footnotesize 32b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void display_scrap_numbers(html_file, scraps)@\\
\mbox{}\verb@     FILE *html_file;@\\
\mbox{}\verb@     Scrap_Node *scraps;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  display_scrap_ref(html_file, scraps->scrap);@\\
\mbox{}\verb@  scraps = scraps->next;@\\
\mbox{}\verb@  while (scraps) {@\\
\mbox{}\verb@    fputs(", ", html_file);@\\
\mbox{}\verb@    display_scrap_ref(html_file, scraps->scrap);@\\
\mbox{}\verb@    scraps = scraps->next;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap81}
\verb@"html.c"@ {\footnotesize 32c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void print_scrap_numbers(html_file, scraps)@\\
\mbox{}\verb@     FILE *html_file;@\\
\mbox{}\verb@     Scrap_Node *scraps;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("scrap", html_file);@\\
\mbox{}\verb@  if (scraps->next) fputc('s', html_file);@\\
\mbox{}\verb@  fputc(' ', html_file);@\\
\mbox{}\verb@  display_scrap_numbers(html_file, scraps);@\\
\mbox{}\verb@  fputs(".\n", html_file);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsubsection{Formatting a Scrap}

We must translate HTML special keywords into entities in scraps.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap82}
\verb@"html.c"@ {\footnotesize 33a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void copy_scrap(file)@\\
\mbox{}\verb@     FILE *file;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int indent = 0;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (1) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case '@{\tt @}\verb@':  @$\langle$Check HTML at-sequence for end-of-scrap {\footnotesize 33b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '<' : fputs("&lt;", file);@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '>' : fputs("&gt;", file);@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '&' : fputs("&amp;", file);@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\n': fputc(c, file);@\\
\mbox{}\verb@                 indent = 0;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\t': @$\langle$Expand tab into spaces {\footnotesize 22b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      default:   putc(c, file);@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap83}
$\langle$Check HTML at-sequence for end-of-scrap {\footnotesize 33b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': fputc(c, file);@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '|': @$\langle$Skip over index entries {\footnotesize 23a}$\rangle$\verb@@\\
\mbox{}\verb@    case '}': return;@\\
\mbox{}\verb@    case '<': @$\langle$Format HTML macro name {\footnotesize 34a}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    default:  /* ignore these since pass1 will have warned about them */@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 33a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
There's no need to check for errors here, since we will have already
pointed out any during the first pass.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap84}
$\langle$Format HTML macro name {\footnotesize 34a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_scrap_name();@\\
\mbox{}\verb@  fprintf(file, "&lt;%s ", name->spelling);@\\
\mbox{}\verb@  if (name->defs)@\\
\mbox{}\verb@    @$\langle$Write HTML abbreviated definition list {\footnotesize 34b}$\rangle$\verb@@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    putc('?', file);@\\
\mbox{}\verb@    fprintf(stderr, "%s: scrap never defined <%s>\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fputs("&gt;", file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 33b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap85}
$\langle$Write HTML abbreviated definition list {\footnotesize 34b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->defs;@\\
\mbox{}\verb@  display_scrap_ref(file, p->scrap);@\\
\mbox{}\verb@  if (p->next)@\\
\mbox{}\verb@    fputs(", ... ", file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 34a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Generating the Indices}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap86}
$\langle$Write HTML index of file names {\footnotesize 34c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (file_names) {@\\
\mbox{}\verb@    fputs("\\begin{rawhtml}\n", html_file);@\\
\mbox{}\verb@    fputs("<dl compact>\n", html_file);@\\
\mbox{}\verb@    format_entry(file_names, html_file, TRUE);@\\
\mbox{}\verb@    fputs("</dl>\n", html_file);@\\
\mbox{}\verb@    fputs("\\end{rawhtml}\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 29.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap87}
$\langle$Write HTML index of macro names {\footnotesize 34d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (macro_names) {@\\
\mbox{}\verb@    fputs("\\begin{rawhtml}\n", html_file);@\\
\mbox{}\verb@    fputs("<dl compact>\n", html_file);@\\
\mbox{}\verb@    format_entry(macro_names, html_file, FALSE);@\\
\mbox{}\verb@    fputs("</dl>\n", html_file);@\\
\mbox{}\verb@    fputs("\\end{rawhtml}\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 29.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap88}
\verb@"html.c"@ {\footnotesize 35a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void format_entry(name, html_file, file_flag)@\\
\mbox{}\verb@     Name *name;@\\
\mbox{}\verb@     FILE *html_file;@\\
\mbox{}\verb@     int file_flag;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (name) {@\\
\mbox{}\verb@    format_entry(name->llink, html_file, file_flag);@\\
\mbox{}\verb@    @$\langle$Format an HTML index entry {\footnotesize 35b}$\rangle$\verb@@\\
\mbox{}\verb@    name = name->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap89}
$\langle$Format an HTML index entry {\footnotesize 35b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("<dt> ", html_file);@\\
\mbox{}\verb@  if (file_flag) {@\\
\mbox{}\verb@    fprintf(html_file, "<code>\"%s\"</code>\n<dd> ", name->spelling);@\\
\mbox{}\verb@    @$\langle$Write HTML file's defining scrap numbers {\footnotesize 35c}$\rangle$\verb@@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    fprintf(html_file, "&lt;%s ", name->spelling);@\\
\mbox{}\verb@    @$\langle$Write HTML defining scrap numbers {\footnotesize 35d}$\rangle$\verb@@\\
\mbox{}\verb@    fputs("&gt;\n<dd> ", html_file);@\\
\mbox{}\verb@    @$\langle$Write HTML referencing scrap numbers {\footnotesize 36a}$\rangle$\verb@@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  putc('\n', html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 35a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap90}
$\langle$Write HTML file's defining scrap numbers {\footnotesize 35c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fputs("Defined by ", html_file);@\\
\mbox{}\verb@  print_scrap_numbers(html_file, name->defs);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 35b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap91}
$\langle$Write HTML defining scrap numbers {\footnotesize 35d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (name->defs)@\\
\mbox{}\verb@    display_scrap_numbers(html_file, name->defs);@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    putc('?', html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 35b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap92}
$\langle$Write HTML referencing scrap numbers {\footnotesize 36a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *p = name->uses;@\\
\mbox{}\verb@  if (p) {@\\
\mbox{}\verb@    fputs("Referenced in ", html_file);@\\
\mbox{}\verb@    print_scrap_numbers(html_file, p);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    fputs("Not referenced.\n", html_file);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 35b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap93}
$\langle$Write HTML index of user-specified names {\footnotesize 36b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (user_names) {@\\
\mbox{}\verb@    fputs("\\begin{rawhtml}\n", html_file);@\\
\mbox{}\verb@    fputs("<dl compact>\n", html_file);@\\
\mbox{}\verb@    format_user_entry(user_names, html_file);@\\
\mbox{}\verb@    fputs("</dl>\n", html_file);@\\
\mbox{}\verb@    fputs("\\end{rawhtml}\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 29.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap94}
\verb@"html.c"@ {\footnotesize 36c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void format_user_entry(name, html_file)@\\
\mbox{}\verb@     Name *name;@\\
\mbox{}\verb@     FILE *html_file;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (name) {@\\
\mbox{}\verb@    format_user_entry(name->llink, html_file);@\\
\mbox{}\verb@    @$\langle$Format a user HTML index entry {\footnotesize 37a}$\rangle$\verb@@\\
\mbox{}\verb@    name = name->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap95}
$\langle$Format a user HTML index entry {\footnotesize 37a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Scrap_Node *uses = name->uses;@\\
\mbox{}\verb@  if (uses) {@\\
\mbox{}\verb@    Scrap_Node *defs = name->defs;@\\
\mbox{}\verb@    fprintf(html_file, "<dt><code>%s</code>:\n<dd> ", name->spelling);@\\
\mbox{}\verb@    if (uses->scrap < defs->scrap) {@\\
\mbox{}\verb@      display_scrap_ref(html_file, uses->scrap);@\\
\mbox{}\verb@      uses = uses->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      if (defs->scrap == uses->scrap)@\\
\mbox{}\verb@        uses = uses->next;@\\
\mbox{}\verb@      fputs("<strong>", html_file);@\\
\mbox{}\verb@      display_scrap_ref(html_file, defs->scrap);@\\
\mbox{}\verb@      fputs("</strong>", html_file);@\\
\mbox{}\verb@      defs = defs->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    while (uses || defs) {@\\
\mbox{}\verb@      fputs(", ", html_file);@\\
\mbox{}\verb@      if (uses && (!defs || uses->scrap < defs->scrap)) {@\\
\mbox{}\verb@        display_scrap_ref(html_file, uses->scrap);@\\
\mbox{}\verb@        uses = uses->next;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@      else {@\\
\mbox{}\verb@        if (uses && defs->scrap == uses->scrap)@\\
\mbox{}\verb@          uses = uses->next;@\\
\mbox{}\verb@        fputs("<strong>", html_file);@\\
\mbox{}\verb@        display_scrap_ref(html_file, defs->scrap);@\\
\mbox{}\verb@        fputs("</strong>", html_file);@\\
\mbox{}\verb@        defs = defs->next;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    fputs(".\n", html_file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 36c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Writing the Output Files} \label{output-files}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap96}
$\langle$Function prototypes {\footnotesize 37b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void write_files();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap97}
\verb@"output.c"@ {\footnotesize 37c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void write_files(files)@\\
\mbox{}\verb@     Name *files;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (files) {@\\
\mbox{}\verb@    write_files(files->llink);@\\
\mbox{}\verb@    @$\langle$Write out \verb|files->spelling| {\footnotesize 38a}$\rangle$\verb@@\\
\mbox{}\verb@    files = files->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 8f, 37c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We call \verb|tempnam|, causing it to create a file name in the
current directory.  This could cause a problem for \verb|rename| if
the eventual output file will reside on a different file system.
Perhaps it would be better to examine \verb|files->spelling| to find
any directory information.

Note the superfluous call to \verb|remove| before \verb|rename|.
We're using it get around a bug in some implementations of
\verb|rename|.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap98}
$\langle$Write out \verb|files->spelling| {\footnotesize 38a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char indent_chars[500];@\\
\mbox{}\verb@  FILE *temp_file;@\\
\mbox{}\verb@  char *temp_name = tempnam(".", 0);@\\
\mbox{}\verb@  temp_file = fopen(temp_name, "w");@\\
\mbox{}\verb@  if (!temp_file) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: can't create %s for a temporary file\n",@\\
\mbox{}\verb@            command_name, temp_name);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }  @\\
\mbox{}\verb@  if (verbose_flag)@\\
\mbox{}\verb@    fprintf(stderr, "writing %s\n", files->spelling);@\\
\mbox{}\verb@  write_scraps(temp_file, files->defs, 0, indent_chars,@\\
\mbox{}\verb@               files->debug_flag, files->tab_flag, files->indent_flag);@\\
\mbox{}\verb@  fclose(temp_file);@\\
\mbox{}\verb@  if (compare_flag)@\\
\mbox{}\verb@    @$\langle$Compare the temp file and the old file {\footnotesize 38b}$\rangle$\verb@@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    remove(files->spelling);@\\
\mbox{}\verb@    rename(temp_name, files->spelling);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 37c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Again, we use a call to \verb|remove| before \verb|rename|.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap99}
$\langle$Compare the temp file and the old file {\footnotesize 38b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  FILE *old_file = fopen(files->spelling, "r");@\\
\mbox{}\verb@  if (old_file) {@\\
\mbox{}\verb@    int x, y;@\\
\mbox{}\verb@    temp_file = fopen(temp_name, "r");@\\
\mbox{}\verb@    do {@\\
\mbox{}\verb@      x = getc(old_file);@\\
\mbox{}\verb@      y = getc(temp_file);@\\
\mbox{}\verb@    } while (x == y && x != EOF);@\\
\mbox{}\verb@    fclose(old_file);@\\
\mbox{}\verb@    fclose(temp_file);@\\
\mbox{}\verb@    if (x == y)@\\
\mbox{}\verb@      remove(temp_name);@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      remove(files->spelling);@\\
\mbox{}\verb@      rename(temp_name, files->spelling);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    rename(temp_name, files->spelling);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 38a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\chapter{The Support Routines}

\section{Source Files} \label{source-files}

\subsection{Global Declarations}

We need two routines to handle reading the source files.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap100}
$\langle$Function prototypes {\footnotesize 39a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void source_open(); /* pass in the name of the source file */@\\
\mbox{}\verb@extern int source_get();   /* no args; returns the next char or EOF */@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
There are also two global variables maintained for use in error
messages and such.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap101}
$\langle$Global variable declarations {\footnotesize 39b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern char *source_name;  /* name of the current file */@\\
\mbox{}\verb@extern int source_line;    /* current line in the source file */@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10ac, 39b, 44d, 53b.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap102}
$\langle$Global variable definitions {\footnotesize 39c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@char *source_name = NULL;@\\
\mbox{}\verb@int source_line = 0;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10bd, 39c, 45a, 53c.
\item Macro referenced in scrap 9e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Local Declarations}


\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap103}
\verb@"input.c"@ {\footnotesize 39d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static FILE *source_file;  /* the current input file */@\\
\mbox{}\verb@static int source_peek;@\\
\mbox{}\verb@static int double_at;@\\
\mbox{}\verb@static int include_depth;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9a, 39d, 40ab, 42c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap104}
\verb@"input.c"@ {\footnotesize 40a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static struct {@\\
\mbox{}\verb@  FILE *file;@\\
\mbox{}\verb@  char *name;@\\
\mbox{}\verb@  int line;@\\
\mbox{}\verb@} stack[10];@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9a, 39d, 40ab, 42c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Reading a File}

The routine \verb|source_get| returns the next character from the
current source file. It notices newlines and keeps the line counter 
\verb|source_line| up to date. It also catches \verb|EOF| and watches
for \verb|@|~characters. All other characters are immediately returned.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap105}
\verb@"input.c"@ {\footnotesize 40b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int source_get()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int c = source_peek;@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case EOF:  @$\langle$Handle \verb|EOF| {\footnotesize 42b}$\rangle$\verb@@\\
\mbox{}\verb@               return c;@\\
\mbox{}\verb@    case '@{\tt @}\verb@':  @$\langle$Handle an ``at'' character {\footnotesize 41a}$\rangle$\verb@@\\
\mbox{}\verb@               return c;@\\
\mbox{}\verb@    case '\n': source_line++;@\\
\mbox{}\verb@    default:   source_peek = getc(source_file);@\\
\mbox{}\verb@               return c;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9a, 39d, 40ab, 42c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
This whole \verb|@|~character handling mess is pretty annoying.
I want to recognize \verb|@i| so I can handle include files correctly.
At the same time, it makes sense to recognize illegal \verb|@|~sequences
and complain; this avoids ever having to check anywhere else.
Unfortunately, I need to avoid tripping over the \verb|@@|~sequence;
hence this whole unsatisfactory \verb|double_at| business.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap106}
$\langle$Handle an ``at'' character {\footnotesize 41a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = getc(source_file);@\\
\mbox{}\verb@  if (double_at) {@\\
\mbox{}\verb@    source_peek = c;@\\
\mbox{}\verb@    double_at = FALSE;@\\
\mbox{}\verb@    c = '@{\tt @}\verb@';@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case 'i': @$\langle$Open an include file {\footnotesize 41b}$\rangle$\verb@@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case 'f': case 'm': case 'u':@\\
\mbox{}\verb@      case 'd': case 'o': case 'D': case 'O':@\\
\mbox{}\verb@      case '{': case '}': case '<': case '>': case '|':@\\
\mbox{}\verb@                source_peek = c;@\\
\mbox{}\verb@                c = '@{\tt @}\verb@';@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      case '@{\tt @}\verb@': source_peek = c;@\\
\mbox{}\verb@                double_at = TRUE;@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      default:  fprintf(stderr, "%s: bad @{\tt @}\verb@ sequence (%s, line %d)\n",@\\
\mbox{}\verb@                        command_name, source_name, source_line);@\\
\mbox{}\verb@                exit(-1);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 40b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap107}
$\langle$Open an include file {\footnotesize 41b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char name[100];@\\
\mbox{}\verb@  if (include_depth >= 10) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: include nesting too deep (%s, %d)\n",@\\
\mbox{}\verb@            command_name, source_name, source_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Collect include-file name {\footnotesize 42a}$\rangle$\verb@@\\
\mbox{}\verb@  stack[include_depth].name = source_name;@\\
\mbox{}\verb@  stack[include_depth].file = source_file;@\\
\mbox{}\verb@  stack[include_depth].line = source_line + 1;@\\
\mbox{}\verb@  include_depth++;@\\
\mbox{}\verb@  source_line = 1;@\\
\mbox{}\verb@  source_name = save_string(name);@\\
\mbox{}\verb@  source_file = fopen(source_name, "r");@\\
\mbox{}\verb@  if (!source_file) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: can't open include file %s\n",@\\
\mbox{}\verb@     command_name, source_name);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  source_peek = getc(source_file);@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 41a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap108}
$\langle$Collect include-file name {\footnotesize 42a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@    char *p = name;@\\
\mbox{}\verb@    do @\\
\mbox{}\verb@      c = getc(source_file);@\\
\mbox{}\verb@    while (c == ' ' || c == '\t');@\\
\mbox{}\verb@    while (isgraph(c)) {@\\
\mbox{}\verb@      *p++ = c;@\\
\mbox{}\verb@      c = getc(source_file);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    *p = '\0';@\\
\mbox{}\verb@    if (c != '\n') {@\\
\mbox{}\verb@      fprintf(stderr, "%s: unexpected characters after file name (%s, %d)\n",@\\
\mbox{}\verb@              command_name, source_name, source_line);@\\
\mbox{}\verb@      exit(-1);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 41b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
If an \verb|EOF| is discovered, the current file must be closed and
input from the next stacked file must be resumed. If no more files are
on the stack, the \verb|EOF| is returned.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap109}
$\langle$Handle \verb|EOF| {\footnotesize 42b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  fclose(source_file);@\\
\mbox{}\verb@  if (include_depth) {@\\
\mbox{}\verb@    include_depth--;@\\
\mbox{}\verb@    source_file = stack[include_depth].file;@\\
\mbox{}\verb@    source_line = stack[include_depth].line;@\\
\mbox{}\verb@    source_name = stack[include_depth].name;@\\
\mbox{}\verb@    source_peek = getc(source_file);@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 40b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Opening a File}

The routine \verb|source_open| takes a file name and tries to open the
file. If unsuccessful, it complains and halts. Otherwise, it sets 
\verb|source_name|, \verb|source_line|, and \verb|double_at|.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap110}
\verb@"input.c"@ {\footnotesize 42c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void source_open(name)@\\
\mbox{}\verb@     char *name;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  source_file = fopen(name, "r");@\\
\mbox{}\verb@  if (!source_file) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: couldn't open %s\n", command_name, name);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  source_name = name;@\\
\mbox{}\verb@  source_line = 1;@\\
\mbox{}\verb@  source_peek = getc(source_file);@\\
\mbox{}\verb@  double_at = FALSE;@\\
\mbox{}\verb@  include_depth = 0;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9a, 39d, 40ab, 42c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Scraps} \label{scraps}


\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap111}
\verb@"scraps.c"@ {\footnotesize 43a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#define SLAB_SIZE 500@\\
\mbox{}\verb@@\\
\mbox{}\verb@typedef struct slab {@\\
\mbox{}\verb@  struct slab *next;@\\
\mbox{}\verb@  char chars[SLAB_SIZE];@\\
\mbox{}\verb@} Slab;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap112}
\verb@"scraps.c"@ {\footnotesize 43b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct {@\\
\mbox{}\verb@  char *file_name;@\\
\mbox{}\verb@  int file_line;@\\
\mbox{}\verb@  int page;@\\
\mbox{}\verb@  char letter;@\\
\mbox{}\verb@  Slab *slab;@\\
\mbox{}\verb@} ScrapEntry;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap113}
\verb@"scraps.c"@ {\footnotesize 43c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static ScrapEntry *SCRAP[256];@\\
\mbox{}\verb@@\\
\mbox{}\verb@#define scrap_array(i) SCRAP[(i) >> 8][(i) & 255]@\\
\mbox{}\verb@@\\
\mbox{}\verb@static int scraps;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap114}
$\langle$Function prototypes {\footnotesize 43d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void init_scraps();@\\
\mbox{}\verb@extern int collect_scrap();@\\
\mbox{}\verb@extern int write_scraps();@\\
\mbox{}\verb@extern void write_scrap_ref();@\\
\mbox{}\verb@extern void write_single_scrap_ref();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap115}
\verb@"scraps.c"@ {\footnotesize 43e }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void init_scraps()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  scraps = 1;@\\
\mbox{}\verb@  SCRAP[0] = (ScrapEntry *) arena_getmem(256 * sizeof(ScrapEntry));@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap116}
\verb@"scraps.c"@ {\footnotesize 44a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void write_scrap_ref(file, num, first, page)@\\
\mbox{}\verb@     FILE *file;@\\
\mbox{}\verb@     int num;@\\
\mbox{}\verb@     int first;@\\
\mbox{}\verb@     int *page;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  if (scrap_array(num).page >= 0) {@\\
\mbox{}\verb@    if (first)@\\
\mbox{}\verb@      fprintf(file, "%d", scrap_array(num).page);@\\
\mbox{}\verb@    else if (scrap_array(num).page != *page)@\\
\mbox{}\verb@      fprintf(file, ", %d", scrap_array(num).page);@\\
\mbox{}\verb@    if (scrap_array(num).letter > 0)@\\
\mbox{}\verb@      fputc(scrap_array(num).letter, file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    if (first)@\\
\mbox{}\verb@      putc('?', file);@\\
\mbox{}\verb@    else@\\
\mbox{}\verb@      fputs(", ?", file);@\\
\mbox{}\verb@    @$\langle$Warn (only once) about needing to rerun after Latex {\footnotesize 44c}$\rangle$\verb@@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  *page = scrap_array(num).page;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap117}
\verb@"scraps.c"@ {\footnotesize 44b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void write_single_scrap_ref(file, num)@\\
\mbox{}\verb@     FILE *file;@\\
\mbox{}\verb@     int num;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int page;@\\
\mbox{}\verb@  write_scrap_ref(file, num, TRUE, &page);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap118}
$\langle$Warn (only once) about needing to rerun after Latex {\footnotesize 44c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (!already_warned) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: you'll need to rerun nuweb after running latex\n",@\\
\mbox{}\verb@            command_name);@\\
\mbox{}\verb@    already_warned = TRUE;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 44a, 52a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap119}
$\langle$Global variable declarations {\footnotesize 44d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern int already_warned;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10ac, 39b, 44d, 53b.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap120}
$\langle$Global variable definitions {\footnotesize 45a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int already_warned = 0;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10bd, 39c, 45a, 53c.
\item Macro referenced in scrap 9e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap121}
\verb@"scraps.c"@ {\footnotesize 45b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct {@\\
\mbox{}\verb@  Slab *scrap;@\\
\mbox{}\verb@  Slab *prev;@\\
\mbox{}\verb@  int index;@\\
\mbox{}\verb@} Manager;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap122}
\verb@"scraps.c"@ {\footnotesize 45c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void push(c, manager)@\\
\mbox{}\verb@     char c;@\\
\mbox{}\verb@     Manager *manager;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Slab *scrap = manager->scrap;@\\
\mbox{}\verb@  int index = manager->index;@\\
\mbox{}\verb@  scrap->chars[index++] = c;@\\
\mbox{}\verb@  if (index == SLAB_SIZE) {@\\
\mbox{}\verb@    Slab *new = (Slab *) arena_getmem(sizeof(Slab));@\\
\mbox{}\verb@    scrap->next = new;@\\
\mbox{}\verb@    manager->scrap = new;@\\
\mbox{}\verb@    index = 0;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  manager->index = index;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap123}
\verb@"scraps.c"@ {\footnotesize 45d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void pushs(s, manager)@\\
\mbox{}\verb@     char *s;@\\
\mbox{}\verb@     Manager *manager;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (*s)@\\
\mbox{}\verb@    push(*s++, manager);@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap124}
\verb@"scraps.c"@ {\footnotesize 45e }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int collect_scrap()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Manager writer;@\\
\mbox{}\verb@  @$\langle$Create new scrap, managed by \verb|writer| {\footnotesize 46a}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Accumulate scrap and return \verb|scraps++| {\footnotesize 46b}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap125}
$\langle$Create new scrap, managed by \verb|writer| {\footnotesize 46a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Slab *scrap = (Slab *) arena_getmem(sizeof(Slab));@\\
\mbox{}\verb@  if ((scraps & 255) == 0)@\\
\mbox{}\verb@    SCRAP[scraps >> 8] = (ScrapEntry *) arena_getmem(256 * sizeof(ScrapEntry));@\\
\mbox{}\verb@  scrap_array(scraps).slab = scrap;@\\
\mbox{}\verb@  scrap_array(scraps).file_name = save_string(source_name);@\\
\mbox{}\verb@  scrap_array(scraps).file_line = source_line;@\\
\mbox{}\verb@  scrap_array(scraps).page = -1;@\\
\mbox{}\verb@  scrap_array(scraps).letter = 0;@\\
\mbox{}\verb@  writer.scrap = scrap;@\\
\mbox{}\verb@  writer.index = 0;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 45e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap126}
$\langle$Accumulate scrap and return \verb|scraps++| {\footnotesize 46b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (1) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case EOF: fprintf(stderr, "%s: unexpect EOF in scrap (%s, %d)\n",@\\
\mbox{}\verb@                        command_name, scrap_array(scraps).file_name,@\\
\mbox{}\verb@                        scrap_array(scraps).file_line);@\\
\mbox{}\verb@                exit(-1);@\\
\mbox{}\verb@      case '@{\tt @}\verb@': @$\langle$Handle at-sign during scrap accumulation {\footnotesize 46c}$\rangle$\verb@@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@      default:  push(c, &writer);@\\
\mbox{}\verb@                c = source_get();@\\
\mbox{}\verb@                break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 45e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap127}
$\langle$Handle at-sign during scrap accumulation {\footnotesize 46c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': pushs("@{\tt @}\verb@@{\tt @}\verb@", &writer);@\\
\mbox{}\verb@              c = source_get();@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '|': @$\langle$Collect user-specified index entries {\footnotesize 47a}$\rangle$\verb@@\\
\mbox{}\verb@    case '}': push('\0', &writer);@\\
\mbox{}\verb@              return scraps++;@\\
\mbox{}\verb@    case '<': @$\langle$Handle macro invocation in scrap {\footnotesize 47b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    default : fprintf(stderr, "%s: unexpected @{\tt @}\verb@%c in scrap (%s, %d)\n",@\\
\mbox{}\verb@                      command_name, c, source_name, source_line);@\\
\mbox{}\verb@              exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 46b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap128}
$\langle$Collect user-specified index entries {\footnotesize 47a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  do {@\\
\mbox{}\verb@    char new_name[100];@\\
\mbox{}\verb@    char *p = new_name;@\\
\mbox{}\verb@    do @\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@    while (isspace(c));@\\
\mbox{}\verb@    if (c != '@{\tt @}\verb@') {@\\
\mbox{}\verb@      Name *name;@\\
\mbox{}\verb@      do {@\\
\mbox{}\verb@        *p++ = c;@\\
\mbox{}\verb@        c = source_get();@\\
\mbox{}\verb@      } while (c != '@{\tt @}\verb@' && !isspace(c));@\\
\mbox{}\verb@      *p = '\0';@\\
\mbox{}\verb@      name = name_add(&user_names, new_name);@\\
\mbox{}\verb@      if (!name->defs || name->defs->scrap != scraps) {@\\
\mbox{}\verb@        Scrap_Node *def = (Scrap_Node *) arena_getmem(sizeof(Scrap_Node));@\\
\mbox{}\verb@        def->scrap = scraps;@\\
\mbox{}\verb@        def->next = name->defs;@\\
\mbox{}\verb@        name->defs = def;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  } while (c != '@{\tt @}\verb@');@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  if (c != '}') {@\\
\mbox{}\verb@    fprintf(stderr, "%s: unexpected @{\tt @}\verb@%c in scrap (%s, %d)\n",@\\
\mbox{}\verb@            command_name, c, source_name, source_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 46c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap129}
$\langle$Handle macro invocation in scrap {\footnotesize 47b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = collect_scrap_name();@\\
\mbox{}\verb@  @$\langle$Save macro name {\footnotesize 47c}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Add current scrap to \verb|name|'s uses {\footnotesize 48a}$\rangle$\verb@@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 46c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap130}
$\langle$Save macro name {\footnotesize 47c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char *s = name->spelling;@\\
\mbox{}\verb@  int len = strlen(s) - 1;@\\
\mbox{}\verb@  pushs("@{\tt @}\verb@<", &writer);@\\
\mbox{}\verb@  while (len > 0) {@\\
\mbox{}\verb@    push(*s++, &writer);@\\
\mbox{}\verb@    len--;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (*s == ' ')@\\
\mbox{}\verb@    pushs("...", &writer);@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    push(*s, &writer);@\\
\mbox{}\verb@  pushs("@{\tt @}\verb@>", &writer);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 47b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap131}
$\langle$Add current scrap to \verb|name|'s uses {\footnotesize 48a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (!name->uses || name->uses->scrap != scraps) {@\\
\mbox{}\verb@    Scrap_Node *use = (Scrap_Node *) arena_getmem(sizeof(Scrap_Node));@\\
\mbox{}\verb@    use->scrap = scraps;@\\
\mbox{}\verb@    use->next = name->uses;@\\
\mbox{}\verb@    name->uses = use;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 47b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap132}
\verb@"scraps.c"@ {\footnotesize 48b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static char pop(manager)@\\
\mbox{}\verb@     Manager *manager;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Slab *scrap = manager->scrap;@\\
\mbox{}\verb@  int index = manager->index;@\\
\mbox{}\verb@  char c = scrap->chars[index++];@\\
\mbox{}\verb@  if (index == SLAB_SIZE) {@\\
\mbox{}\verb@    manager->prev = scrap;@\\
\mbox{}\verb@    manager->scrap = scrap->next;@\\
\mbox{}\verb@    index = 0;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  manager->index = index;@\\
\mbox{}\verb@  return c;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap133}
\verb@"scraps.c"@ {\footnotesize 48c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Name *pop_scrap_name(manager)@\\
\mbox{}\verb@     Manager *manager;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char name[100];@\\
\mbox{}\verb@  char *p = name;@\\
\mbox{}\verb@  int c = pop(manager);@\\
\mbox{}\verb@  while (TRUE) {@\\
\mbox{}\verb@    if (c == '@{\tt @}\verb@')@\\
\mbox{}\verb@      @$\langle$Check for end of scrap name and return {\footnotesize 49a}$\rangle$\verb@@\\
\mbox{}\verb@    else {@\\
\mbox{}\verb@      *p++ = c;@\\
\mbox{}\verb@      c = pop(manager);@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap134}
$\langle$Check for end of scrap name and return {\footnotesize 49a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = pop(manager);@\\
\mbox{}\verb@  if (c == '@{\tt @}\verb@') {@\\
\mbox{}\verb@    *p++ = c;@\\
\mbox{}\verb@    c = pop(manager);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else if (c == '>') {@\\
\mbox{}\verb@    if (p - name > 3 && p[-1] == '.' && p[-2] == '.' && p[-3] == '.') {@\\
\mbox{}\verb@      p[-3] = ' ';@\\
\mbox{}\verb@      p -= 2;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    *p = '\0';@\\
\mbox{}\verb@    return prefix_add(&macro_names, name);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    fprintf(stderr, "%s: found an internal problem (1)\n", command_name);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 48c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap135}
\verb@"scraps.c"@ {\footnotesize 49b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@int write_scraps(file, defs, global_indent, indent_chars,@\\
\mbox{}\verb@                   debug_flag, tab_flag, indent_flag)@\\
\mbox{}\verb@     FILE *file;@\\
\mbox{}\verb@     Scrap_Node *defs;@\\
\mbox{}\verb@     int global_indent;@\\
\mbox{}\verb@     char *indent_chars;@\\
\mbox{}\verb@     char debug_flag;@\\
\mbox{}\verb@     char tab_flag;@\\
\mbox{}\verb@     char indent_flag;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int indent = 0;@\\
\mbox{}\verb@  while (defs) {@\\
\mbox{}\verb@    @$\langle$Copy \verb|defs->scrap| to \verb|file| {\footnotesize 50a}$\rangle$\verb@@\\
\mbox{}\verb@    defs = defs->next;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  return indent + global_indent;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap136}
$\langle$Copy \verb|defs->scrap| to \verb|file| {\footnotesize 50a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  char c;@\\
\mbox{}\verb@  Manager reader;@\\
\mbox{}\verb@  int line_number = scrap_array(defs->scrap).file_line;@\\
\mbox{}\verb@  @$\langle$Insert debugging information if required {\footnotesize 50b}$\rangle$\verb@@\\
\mbox{}\verb@  reader.scrap = scrap_array(defs->scrap).slab;@\\
\mbox{}\verb@  reader.index = 0;@\\
\mbox{}\verb@  c = pop(&reader);@\\
\mbox{}\verb@  while (c) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case '@{\tt @}\verb@':  @$\langle$Check for macro invocation in scrap {\footnotesize 51b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\n': putc(c, file);@\\
\mbox{}\verb@                 line_number++;@\\
\mbox{}\verb@                 @$\langle$Insert appropriate indentation {\footnotesize 50c}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\t': @$\langle$Handle tab characters on output {\footnotesize 51a}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      default:   putc(c, file);@\\
\mbox{}\verb@                 indent_chars[global_indent + indent] = ' ';@\\
\mbox{}\verb@                 indent++;@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    c = pop(&reader);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 49b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap137}
$\langle$Insert debugging information if required {\footnotesize 50b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@if (debug_flag) {@\\
\mbox{}\verb@  fprintf(file, "\n#line %d \"%s\"\n",@\\
\mbox{}\verb@          line_number, scrap_array(defs->scrap).file_name);@\\
\mbox{}\verb@  @$\langle$Insert appropriate indentation {\footnotesize 50c}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 50a, 51b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap138}
$\langle$Insert appropriate indentation {\footnotesize 50c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (indent_flag) {@\\
\mbox{}\verb@    if (tab_flag)@\\
\mbox{}\verb@      for (indent=0; indent<global_indent; indent++)@\\
\mbox{}\verb@        putc(' ', file);@\\
\mbox{}\verb@    else@\\
\mbox{}\verb@      for (indent=0; indent<global_indent; indent++)@\\
\mbox{}\verb@        putc(indent_chars[indent], file);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  indent = 0;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 50ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap139}
$\langle$Handle tab characters on output {\footnotesize 51a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (tab_flag)@\\
\mbox{}\verb@    @$\langle$Expand tab into spaces {\footnotesize 22b}$\rangle$\verb@@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    putc('\t', file);@\\
\mbox{}\verb@    indent_chars[global_indent + indent] = '\t';@\\
\mbox{}\verb@    indent++;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 50a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap140}
$\langle$Check for macro invocation in scrap {\footnotesize 51b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = pop(&reader);@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': putc(c, file);@\\
\mbox{}\verb@              indent_chars[global_indent + indent] = ' ';@\\
\mbox{}\verb@              indent++;@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '<': @$\langle$Copy macro into \verb|file| {\footnotesize 51c}$\rangle$\verb@@\\
\mbox{}\verb@              @$\langle$Insert debugging information if required {\footnotesize 50b}$\rangle$\verb@@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    default:  /* ignore, since we should already have a warning */@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 50a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap141}
$\langle$Copy macro into \verb|file| {\footnotesize 51c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *name = pop_scrap_name(&reader);@\\
\mbox{}\verb@  if (name->mark) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: recursive macro discovered involving <%s>\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (name->defs) {@\\
\mbox{}\verb@    name->mark = TRUE;@\\
\mbox{}\verb@    indent = write_scraps(file, name->defs, global_indent + indent,@\\
\mbox{}\verb@                          indent_chars, debug_flag, tab_flag, indent_flag);@\\
\mbox{}\verb@    indent -= global_indent;@\\
\mbox{}\verb@    name->mark = FALSE;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else if (!tex_flag)@\\
\mbox{}\verb@    fprintf(stderr, "%s: macro never defined <%s>\n",@\\
\mbox{}\verb@            command_name, name->spelling);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 51b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Collecting Page Numbers}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap142}
$\langle$Function prototypes {\footnotesize 51d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void collect_numbers();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap143}
\verb@"scraps.c"@ {\footnotesize 52a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void collect_numbers(aux_name)@\\
\mbox{}\verb@     char *aux_name;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  if (number_flag) {@\\
\mbox{}\verb@    int i;@\\
\mbox{}\verb@    for (i=1; i<scraps; i++)@\\
\mbox{}\verb@      scrap_array(i).page = i;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else {@\\
\mbox{}\verb@    FILE *aux_file = fopen(aux_name, "r");@\\
\mbox{}\verb@    already_warned = FALSE;@\\
\mbox{}\verb@    if (aux_file) {@\\
\mbox{}\verb@      char aux_line[500];@\\
\mbox{}\verb@      while (fgets(aux_line, 500, aux_file)) {@\\
\mbox{}\verb@        int scrap_number;@\\
\mbox{}\verb@        int page_number;@\\
\mbox{}\verb@        char dummy[50];@\\
\mbox{}\verb@        if (3 == sscanf(aux_line, "\\newlabel{scrap%d}{%[^}]}{%d}",@\\
\mbox{}\verb@                        &scrap_number, dummy, &page_number)) {@\\
\mbox{}\verb@          if (scrap_number < scraps)@\\
\mbox{}\verb@            scrap_array(scrap_number).page = page_number;@\\
\mbox{}\verb@          else@\\
\mbox{}\verb@            @$\langle$Warn (only once) about needing to rerun after Latex {\footnotesize 44c}$\rangle$\verb@@\\
\mbox{}\verb@        }@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@      fclose(aux_file);@\\
\mbox{}\verb@      @$\langle$Add letters to scraps with duplicate page numbers {\footnotesize 52b}$\rangle$\verb@@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap144}
$\langle$Add letters to scraps with duplicate page numbers {\footnotesize 52b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int scrap;@\\
\mbox{}\verb@  for (scrap=2; scrap<scraps; scrap++) {@\\
\mbox{}\verb@    if (scrap_array(scrap-1).page == scrap_array(scrap).page) {@\\
\mbox{}\verb@      if (!scrap_array(scrap-1).letter)@\\
\mbox{}\verb@        scrap_array(scrap-1).letter = 'a';@\\
\mbox{}\verb@      scrap_array(scrap).letter = scrap_array(scrap-1).letter + 1;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 52a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Names} \label{names}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap145}
$\langle$Type declarations {\footnotesize 52c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct scrap_node {@\\
\mbox{}\verb@  struct scrap_node *next;@\\
\mbox{}\verb@  int scrap;@\\
\mbox{}\verb@} Scrap_Node;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 8a, 52c, 53a.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap146}
$\langle$Type declarations {\footnotesize 53a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct name {@\\
\mbox{}\verb@  char *spelling;@\\
\mbox{}\verb@  struct name *llink;@\\
\mbox{}\verb@  struct name *rlink;@\\
\mbox{}\verb@  Scrap_Node *defs;@\\
\mbox{}\verb@  Scrap_Node *uses;@\\
\mbox{}\verb@  int mark;@\\
\mbox{}\verb@  char tab_flag;@\\
\mbox{}\verb@  char indent_flag;@\\
\mbox{}\verb@  char debug_flag;@\\
\mbox{}\verb@} Name;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 8a, 52c, 53a.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap147}
$\langle$Global variable declarations {\footnotesize 53b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern Name *file_names;@\\
\mbox{}\verb@extern Name *macro_names;@\\
\mbox{}\verb@extern Name *user_names;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10ac, 39b, 44d, 53b.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap148}
$\langle$Global variable definitions {\footnotesize 53c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@Name *file_names = NULL;@\\
\mbox{}\verb@Name *macro_names = NULL;@\\
\mbox{}\verb@Name *user_names = NULL;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 10bd, 39c, 45a, 53c.
\item Macro referenced in scrap 9e.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap149}
$\langle$Function prototypes {\footnotesize 53d}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern Name *collect_file_name();@\\
\mbox{}\verb@extern Name *collect_macro_name();@\\
\mbox{}\verb@extern Name *collect_scrap_name();@\\
\mbox{}\verb@extern Name *name_add();@\\
\mbox{}\verb@extern Name *prefix_add();@\\
\mbox{}\verb@extern char *save_string();@\\
\mbox{}\verb@extern void reverse_lists();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap150}
\verb@"names.c"@ {\footnotesize 54a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@enum { LESS, GREATER, EQUAL, PREFIX, EXTENSION };@\\
\mbox{}\verb@@\\
\mbox{}\verb@static int compare(x, y)@\\
\mbox{}\verb@     char *x;@\\
\mbox{}\verb@     char *y;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int len, result;@\\
\mbox{}\verb@  int xl = strlen(x);@\\
\mbox{}\verb@  int yl = strlen(y);@\\
\mbox{}\verb@  int xp = x[xl - 1] == ' ';@\\
\mbox{}\verb@  int yp = y[yl - 1] == ' ';@\\
\mbox{}\verb@  if (xp) xl--;@\\
\mbox{}\verb@  if (yp) yl--;@\\
\mbox{}\verb@  len = xl < yl ? xl : yl;@\\
\mbox{}\verb@  result = strncmp(x, y, len);@\\
\mbox{}\verb@  if (result < 0) return GREATER;@\\
\mbox{}\verb@  else if (result > 0) return LESS;@\\
\mbox{}\verb@  else if (xl < yl) {@\\
\mbox{}\verb@    if (xp) return EXTENSION;@\\
\mbox{}\verb@    else return LESS;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else if (xl > yl) {@\\
\mbox{}\verb@    if (yp) return PREFIX;@\\
\mbox{}\verb@    else return GREATER;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  else return EQUAL;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap151}
\verb@"names.c"@ {\footnotesize 54b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@char *save_string(s)@\\
\mbox{}\verb@     char *s;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char *new = (char *) arena_getmem((strlen(s) + 1) * sizeof(char));@\\
\mbox{}\verb@  strcpy(new, s);@\\
\mbox{}\verb@  return new;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap152}
\verb@"names.c"@ {\footnotesize 55a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static int ambiguous_prefix();@\\
\mbox{}\verb@@\\
\mbox{}\verb@Name *prefix_add(root, spelling)@\\
\mbox{}\verb@     Name **root;@\\
\mbox{}\verb@     char *spelling;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *node = *root;@\\
\mbox{}\verb@  while (node) {@\\
\mbox{}\verb@    switch (compare(node->spelling, spelling)) {@\\
\mbox{}\verb@    case GREATER:   root = &node->rlink;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@    case LESS:      root = &node->llink;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@    case EQUAL:     return node;@\\
\mbox{}\verb@    case EXTENSION: node->spelling = save_string(spelling);@\\
\mbox{}\verb@                    return node;@\\
\mbox{}\verb@    case PREFIX:    @$\langle$Check for ambiguous prefix {\footnotesize 55b}$\rangle$\verb@@\\
\mbox{}\verb@                    return node;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    node = *root;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Create new name entry {\footnotesize 58a}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Since a very short prefix might match more than one macro name, I need
to check for other matches to avoid mistakes. Basically, I simply
continue the search down {\em both\/} branches of the tree.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap153}
$\langle$Check for ambiguous prefix {\footnotesize 55b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (ambiguous_prefix(node->llink, spelling) ||@\\
\mbox{}\verb@      ambiguous_prefix(node->rlink, spelling))@\\
\mbox{}\verb@    fprintf(stderr,@\\
\mbox{}\verb@            "%s: ambiguous prefix @{\tt @}\verb@<%s...@{\tt @}\verb@> (%s, line %d)\n",@\\
\mbox{}\verb@            command_name, spelling, source_name, source_line);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 55a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap154}
\verb@"names.c"@ {\footnotesize 56 }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static int ambiguous_prefix(node, spelling)@\\
\mbox{}\verb@     Name *node;@\\
\mbox{}\verb@     char *spelling;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (node) {@\\
\mbox{}\verb@    switch (compare(node->spelling, spelling)) {@\\
\mbox{}\verb@    case GREATER:   node = node->rlink;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@    case LESS:      node = node->llink;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@    case EQUAL:@\\
\mbox{}\verb@    case EXTENSION:@\\
\mbox{}\verb@    case PREFIX:    return TRUE;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  return FALSE;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Rob Shillingsburg suggested that I organize the index of
user-specified identifiers more traditionally; that is, not relying on
strict {\small ASCII} comparisons via \verb|strcmp|. Ideally, we'd like
to see the index ordered like this:
\begin{quote}
\begin{flushleft}
aardvark \\
Adam \\
atom \\
Atomic \\
atoms
\end{flushleft}
\end{quote}
The function \verb|robs_strcmp| implements the desired predicate.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap155}
\verb@"names.c"@ {\footnotesize 57a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static int robs_strcmp(x, y)@\\
\mbox{}\verb@     char *x;@\\
\mbox{}\verb@     char *y;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char *xx = x;@\\
\mbox{}\verb@  char *yy = y;@\\
\mbox{}\verb@  int xc = toupper(*xx);@\\
\mbox{}\verb@  int yc = toupper(*yy);@\\
\mbox{}\verb@  while (xc == yc && xc) {@\\
\mbox{}\verb@    xx++;@\\
\mbox{}\verb@    yy++;@\\
\mbox{}\verb@    xc = toupper(*xx);@\\
\mbox{}\verb@    yc = toupper(*yy);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (xc != yc) return xc - yc;@\\
\mbox{}\verb@  xc = *x;@\\
\mbox{}\verb@  yc = *y;@\\
\mbox{}\verb@  while (xc == yc && xc) {@\\
\mbox{}\verb@    x++;@\\
\mbox{}\verb@    y++;@\\
\mbox{}\verb@    xc = *x;@\\
\mbox{}\verb@    yc = *y;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (isupper(xc) && islower(yc))@\\
\mbox{}\verb@    return xc * 2 - (toupper(yc) * 2 + 1);@\\
\mbox{}\verb@  if (islower(xc) && isupper(yc))@\\
\mbox{}\verb@    return toupper(xc) * 2 + 1 - yc * 2;@\\
\mbox{}\verb@  return xc - yc;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap156}
\verb@"names.c"@ {\footnotesize 57b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@Name *name_add(root, spelling)@\\
\mbox{}\verb@     Name **root;@\\
\mbox{}\verb@     char *spelling;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *node = *root;@\\
\mbox{}\verb@  while (node) {@\\
\mbox{}\verb@    int result = robs_strcmp(node->spelling, spelling);@\\
\mbox{}\verb@    if (result > 0)@\\
\mbox{}\verb@      root = &node->llink;@\\
\mbox{}\verb@    else if (result < 0)@\\
\mbox{}\verb@      root = &node->rlink;@\\
\mbox{}\verb@    else@\\
\mbox{}\verb@      return node;@\\
\mbox{}\verb@    node = *root;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Create new name entry {\footnotesize 58a}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap157}
$\langle$Create new name entry {\footnotesize 58a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  node = (Name *) arena_getmem(sizeof(Name));@\\
\mbox{}\verb@  node->spelling = save_string(spelling);@\\
\mbox{}\verb@  node->mark = FALSE;@\\
\mbox{}\verb@  node->llink = NULL;@\\
\mbox{}\verb@  node->rlink = NULL;@\\
\mbox{}\verb@  node->uses = NULL;@\\
\mbox{}\verb@  node->defs = NULL;@\\
\mbox{}\verb@  node->tab_flag = TRUE;@\\
\mbox{}\verb@  node->indent_flag = TRUE;@\\
\mbox{}\verb@  node->debug_flag = FALSE;@\\
\mbox{}\verb@  *root = node;@\\
\mbox{}\verb@  return node;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 55a, 57b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Name terminated by whitespace.  Also check for ``per-file'' flags. Keep
skipping white space until we reach scrap.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap158}
\verb@"names.c"@ {\footnotesize 58b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@Name *collect_file_name()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Name *new_name;@\\
\mbox{}\verb@  char name[100];@\\
\mbox{}\verb@  char *p = name;@\\
\mbox{}\verb@  int start_line = source_line;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (isspace(c))@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  while (isgraph(c)) {@\\
\mbox{}\verb@    *p++ = c;@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (p == name) {@\\
\mbox{}\verb@    fprintf(stderr, "%s: expected file name (%s, %d)\n",@\\
\mbox{}\verb@            command_name, source_name, start_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  *p = '\0';@\\
\mbox{}\verb@  new_name = name_add(&file_names, name);@\\
\mbox{}\verb@  @$\langle$Handle optional per-file flags {\footnotesize 59}$\rangle$\verb@@\\
\mbox{}\verb@  if (c != '@{\tt @}\verb@' || source_get() != '{') {@\\
\mbox{}\verb@    fprintf(stderr, "%s: expected @{\tt @}\verb@{ after file name (%s, %d)\n",@\\
\mbox{}\verb@            command_name, source_name, start_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  return new_name;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap159}
$\langle$Handle optional per-file flags {\footnotesize 59}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  while (1) {@\\
\mbox{}\verb@    while (isspace(c))@\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@    if (c == '-') {@\\
\mbox{}\verb@      c = source_get();@\\
\mbox{}\verb@      do {@\\
\mbox{}\verb@        switch (c) {@\\
\mbox{}\verb@          case 't': new_name->tab_flag = FALSE;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@          case 'd': new_name->debug_flag = TRUE;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@          case 'i': new_name->indent_flag = FALSE;@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@          default : fprintf(stderr, "%s: unexpected per-file flag (%s, %d)\n",@\\
\mbox{}\verb@                            command_name, source_name, source_line);@\\
\mbox{}\verb@                    break;@\\
\mbox{}\verb@        }@\\
\mbox{}\verb@        c = source_get();@\\
\mbox{}\verb@      } while (!isspace(c));@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    else break;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 58b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Name terminated by \verb+\n+ or \verb+@{+; but keep skipping until \verb+@{+
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap160}
\verb@"names.c"@ {\footnotesize 60a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@Name *collect_macro_name()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char name[100];@\\
\mbox{}\verb@  char *p = name;@\\
\mbox{}\verb@  int start_line = source_line;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (isspace(c))@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  while (c != EOF) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case '@{\tt @}\verb@':  @$\langle$Check for terminating at-sequence and return name {\footnotesize 60b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\t':@\\
\mbox{}\verb@      case ' ':  *p++ = ' ';@\\
\mbox{}\verb@                 do@\\
\mbox{}\verb@                   c = source_get();@\\
\mbox{}\verb@                 while (c == ' ' || c == '\t');@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\n': @$\langle$Skip until scrap begins, then return name {\footnotesize 61b}$\rangle$\verb@@\\
\mbox{}\verb@      default:   *p++ = c;@\\
\mbox{}\verb@                 c = source_get();@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fprintf(stderr, "%s: expected macro name (%s, %d)\n",@\\
\mbox{}\verb@          command_name, source_name, start_line);@\\
\mbox{}\verb@  exit(-1);@\\
\mbox{}\verb@  return NULL;  /* unreachable return to avoid warnings on some compilers */@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap161}
$\langle$Check for terminating at-sequence and return name {\footnotesize 60b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': *p++ = c;@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '{': @$\langle$Cleanup and install name {\footnotesize 61a}$\rangle$\verb@@\\
\mbox{}\verb@    default:  fprintf(stderr,@\\
\mbox{}\verb@                      "%s: unexpected @{\tt @}\verb@%c in macro name (%s, %d)\n",@\\
\mbox{}\verb@                      command_name, c, source_name, start_line);@\\
\mbox{}\verb@              exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 60a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap162}
$\langle$Cleanup and install name {\footnotesize 61a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  if (p > name && p[-1] == ' ')@\\
\mbox{}\verb@    p--;@\\
\mbox{}\verb@  if (p - name > 3 && p[-1] == '.' && p[-2] == '.' && p[-3] == '.') {@\\
\mbox{}\verb@    p[-3] = ' ';@\\
\mbox{}\verb@    p -= 2;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  if (p == name || name[0] == ' ') {@\\
\mbox{}\verb@    fprintf(stderr, "%s: empty scrap name (%s, %d)\n",@\\
\mbox{}\verb@            command_name, source_name, source_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  *p = '\0';@\\
\mbox{}\verb@  return prefix_add(&macro_names, name);@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scraps 60b, 61b, 62b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap163}
$\langle$Skip until scrap begins, then return name {\footnotesize 61b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  do@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  while (isspace(c));@\\
\mbox{}\verb@  if (c != '@{\tt @}\verb@' || source_get() != '{') {@\\
\mbox{}\verb@    fprintf(stderr, "%s: expected @{\tt @}\verb@{ after macro name (%s, %d)\n",@\\
\mbox{}\verb@            command_name, source_name, start_line);@\\
\mbox{}\verb@    exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Cleanup and install name {\footnotesize 61a}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 60a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Terminated by \verb+@>+
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap164}
\verb@"names.c"@ {\footnotesize 62a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@Name *collect_scrap_name()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char name[100];@\\
\mbox{}\verb@  char *p = name;@\\
\mbox{}\verb@  int c = source_get();@\\
\mbox{}\verb@  while (c == ' ' || c == '\t')@\\
\mbox{}\verb@    c = source_get();@\\
\mbox{}\verb@  while (c != EOF) {@\\
\mbox{}\verb@    switch (c) {@\\
\mbox{}\verb@      case '@{\tt @}\verb@':  @$\langle$Look for end of scrap name and return {\footnotesize 62b}$\rangle$\verb@@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      case '\t':@\\
\mbox{}\verb@      case ' ':  *p++ = ' ';@\\
\mbox{}\verb@                 do@\\
\mbox{}\verb@                   c = source_get();@\\
\mbox{}\verb@                 while (c == ' ' || c == '\t');@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@      default:   if (!isgraph(c)) {@\\
\mbox{}\verb@                   fprintf(stderr,@\\
\mbox{}\verb@                           "%s: unexpected character in macro name (%s, %d)\n",@\\
\mbox{}\verb@                           command_name, source_name, source_line);@\\
\mbox{}\verb@                   exit(-1);@\\
\mbox{}\verb@                 }@\\
\mbox{}\verb@                 *p++ = c;@\\
\mbox{}\verb@                 c = source_get();@\\
\mbox{}\verb@                 break;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  fprintf(stderr, "%s: unexpected end of file (%s, %d)\n",@\\
\mbox{}\verb@          command_name, source_name, source_line);@\\
\mbox{}\verb@  exit(-1);@\\
\mbox{}\verb@  return NULL;  /* unreachable return to avoid warnings on some compilers */@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap165}
$\langle$Look for end of scrap name and return {\footnotesize 62b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  c = source_get();@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '@{\tt @}\verb@': *p++ = c;@\\
\mbox{}\verb@              c = source_get();@\\
\mbox{}\verb@              break;@\\
\mbox{}\verb@    case '>': @$\langle$Cleanup and install name {\footnotesize 61a}$\rangle$\verb@@\\
\mbox{}\verb@    default:  fprintf(stderr,@\\
\mbox{}\verb@                      "%s: unexpected @{\tt @}\verb@%c in macro name (%s, %d)\n",@\\
\mbox{}\verb@                      command_name, c, source_name, source_line);@\\
\mbox{}\verb@              exit(-1);@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 62a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap166}
\verb@"names.c"@ {\footnotesize 63a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Scrap_Node *reverse();   /* a forward declaration */@\\
\mbox{}\verb@@\\
\mbox{}\verb@void reverse_lists(names)@\\
\mbox{}\verb@     Name *names;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (names) {@\\
\mbox{}\verb@    reverse_lists(names->llink);@\\
\mbox{}\verb@    names->defs = reverse(names->defs);@\\
\mbox{}\verb@    names->uses = reverse(names->uses);@\\
\mbox{}\verb@    names = names->rlink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
Just for fun, here's a non-recursive version of the traditional list
reversal code. Note that it reverses the list in place; that is, it
does no new allocations.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap167}
\verb@"names.c"@ {\footnotesize 63b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Scrap_Node *reverse(a)@\\
\mbox{}\verb@     Scrap_Node *a;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  if (a) {@\\
\mbox{}\verb@    Scrap_Node *b = a->next;@\\
\mbox{}\verb@    a->next = NULL;@\\
\mbox{}\verb@    while (b) {@\\
\mbox{}\verb@      Scrap_Node *c = b->next;@\\
\mbox{}\verb@      b->next = a;@\\
\mbox{}\verb@      a = b;@\\
\mbox{}\verb@      b = c;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  return a;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Searching for Index Entries} \label{search}

Given the array of scraps and a set of index entries, we need to
search all the scraps for occurrences of each entry. The obvious
approach to this problem would be quite expensive for large documents;
however, there is an interesting  paper describing an efficient
solution~\cite{aho:75}.


\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap168}
\verb@"scraps.c"@ {\footnotesize 63c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct name_node {@\\
\mbox{}\verb@  struct name_node *next;@\\
\mbox{}\verb@  Name *name;@\\
\mbox{}\verb@} Name_Node;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap169}
\verb@"scraps.c"@ {\footnotesize 64a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct goto_node {@\\
\mbox{}\verb@  Name_Node *output;            /* list of words ending in this state */@\\
\mbox{}\verb@  struct move_node *moves;      /* list of possible moves */@\\
\mbox{}\verb@  struct goto_node *fail;       /* and where to go when no move fits */@\\
\mbox{}\verb@  struct goto_node *next;       /* next goto node with same depth */@\\
\mbox{}\verb@} Goto_Node;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap170}
\verb@"scraps.c"@ {\footnotesize 64b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct move_node {@\\
\mbox{}\verb@  struct move_node *next;@\\
\mbox{}\verb@  Goto_Node *state;@\\
\mbox{}\verb@  char c;@\\
\mbox{}\verb@} Move_Node;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap171}
\verb@"scraps.c"@ {\footnotesize 64c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Goto_Node *root[128];@\\
\mbox{}\verb@static int max_depth;@\\
\mbox{}\verb@static Goto_Node **depths;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap172}
\verb@"scraps.c"@ {\footnotesize 64d }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Goto_Node *goto_lookup(c, g)@\\
\mbox{}\verb@     char c;@\\
\mbox{}\verb@     Goto_Node *g;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  Move_Node *m = g->moves;@\\
\mbox{}\verb@  while (m && m->c != c)@\\
\mbox{}\verb@    m = m->next;@\\
\mbox{}\verb@  if (m)@\\
\mbox{}\verb@    return m->state;@\\
\mbox{}\verb@  else@\\
\mbox{}\verb@    return NULL;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Building the Automata}


\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap173}
$\langle$Function prototypes {\footnotesize 64e}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void search();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap174}
\verb@"scraps.c"@ {\footnotesize 65a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void build_gotos();@\\
\mbox{}\verb@static int reject_match();@\\
\mbox{}\verb@@\\
\mbox{}\verb@void search()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int i;@\\
\mbox{}\verb@  for (i=0; i<128; i++)@\\
\mbox{}\verb@    root[i] = NULL;@\\
\mbox{}\verb@  max_depth = 10;@\\
\mbox{}\verb@  depths = (Goto_Node **) arena_getmem(max_depth * sizeof(Goto_Node *));@\\
\mbox{}\verb@  for (i=0; i<max_depth; i++)@\\
\mbox{}\verb@    depths[i] = NULL;@\\
\mbox{}\verb@  build_gotos(user_names);@\\
\mbox{}\verb@  @$\langle$Build failure functions {\footnotesize 67}$\rangle$\verb@@\\
\mbox{}\verb@  @$\langle$Search scraps {\footnotesize 68}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap175}
\verb@"scraps.c"@ {\footnotesize 65b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static void build_gotos(tree)@\\
\mbox{}\verb@     Name *tree;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  while (tree) {@\\
\mbox{}\verb@    @$\langle$Extend goto graph with \verb|tree->spelling| {\footnotesize 66}$\rangle$\verb@@\\
\mbox{}\verb@    build_gotos(tree->rlink);@\\
\mbox{}\verb@    tree = tree->llink;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap176}
$\langle$Extend goto graph with \verb|tree->spelling| {\footnotesize 66}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int depth = 2;@\\
\mbox{}\verb@  char *p = tree->spelling;@\\
\mbox{}\verb@  char c = *p++;@\\
\mbox{}\verb@  Goto_Node *q = root[c];@\\
\mbox{}\verb@  if (!q) {@\\
\mbox{}\verb@    q = (Goto_Node *) arena_getmem(sizeof(Goto_Node));@\\
\mbox{}\verb@    root[c] = q;@\\
\mbox{}\verb@    q->moves = NULL;@\\
\mbox{}\verb@    q->fail = NULL;@\\
\mbox{}\verb@    q->moves = NULL;@\\
\mbox{}\verb@    q->output = NULL;@\\
\mbox{}\verb@    q->next = depths[1];@\\
\mbox{}\verb@    depths[1] = q;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  while (c = *p++) {@\\
\mbox{}\verb@    Goto_Node *new = goto_lookup(c, q);@\\
\mbox{}\verb@    if (!new) {@\\
\mbox{}\verb@      Move_Node *new_move = (Move_Node *) arena_getmem(sizeof(Move_Node));@\\
\mbox{}\verb@      new = (Goto_Node *) arena_getmem(sizeof(Goto_Node));@\\
\mbox{}\verb@      new->moves = NULL;@\\
\mbox{}\verb@      new->fail = NULL;@\\
\mbox{}\verb@      new->moves = NULL;@\\
\mbox{}\verb@      new->output = NULL;@\\
\mbox{}\verb@      new_move->state = new;@\\
\mbox{}\verb@      new_move->c = c;@\\
\mbox{}\verb@      new_move->next = q->moves;@\\
\mbox{}\verb@      q->moves = new_move;@\\
\mbox{}\verb@      if (depth == max_depth) {@\\
\mbox{}\verb@        int i;@\\
\mbox{}\verb@        Goto_Node **new_depths =@\\
\mbox{}\verb@            (Goto_Node **) arena_getmem(2*depth*sizeof(Goto_Node *));@\\
\mbox{}\verb@        max_depth = 2 * depth;@\\
\mbox{}\verb@        for (i=0; i<depth; i++)@\\
\mbox{}\verb@          new_depths[i] = depths[i];@\\
\mbox{}\verb@        depths = new_depths;@\\
\mbox{}\verb@        for (i=depth; i<max_depth; i++)@\\
\mbox{}\verb@          depths[i] = NULL;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@      new->next = depths[depth];@\\
\mbox{}\verb@      depths[depth] = new;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    q = new;@\\
\mbox{}\verb@    depth++;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  q->output = (Name_Node *) arena_getmem(sizeof(Name_Node));@\\
\mbox{}\verb@  q->output->next = NULL;@\\
\mbox{}\verb@  q->output->name = tree;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 65b.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap177}
$\langle$Build failure functions {\footnotesize 67}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  int depth;@\\
\mbox{}\verb@  for (depth=1; depth<max_depth; depth++) {@\\
\mbox{}\verb@    Goto_Node *r = depths[depth];@\\
\mbox{}\verb@    while (r) {@\\
\mbox{}\verb@      Move_Node *m = r->moves;@\\
\mbox{}\verb@      while (m) {@\\
\mbox{}\verb@        char a = m->c;@\\
\mbox{}\verb@        Goto_Node *s = m->state;@\\
\mbox{}\verb@        Goto_Node *state = r->fail;@\\
\mbox{}\verb@        while (state && !goto_lookup(a, state))@\\
\mbox{}\verb@          state = state->fail;@\\
\mbox{}\verb@        if (state)@\\
\mbox{}\verb@          s->fail = goto_lookup(a, state);@\\
\mbox{}\verb@        else@\\
\mbox{}\verb@          s->fail = root[a];@\\
\mbox{}\verb@        if (s->fail) {@\\
\mbox{}\verb@          Name_Node *p = s->fail->output;@\\
\mbox{}\verb@          while (p) {@\\
\mbox{}\verb@            Name_Node *q = (Name_Node *) arena_getmem(sizeof(Name_Node));@\\
\mbox{}\verb@            q->name = p->name;@\\
\mbox{}\verb@            q->next = s->output;@\\
\mbox{}\verb@            s->output = q;@\\
\mbox{}\verb@            p = p->next;@\\
\mbox{}\verb@          }@\\
\mbox{}\verb@        }@\\
\mbox{}\verb@        m = m->next;@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@      r = r->next;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 65a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Searching the Scraps}

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap178}
$\langle$Search scraps {\footnotesize 68}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  for (i=1; i<scraps; i++) {@\\
\mbox{}\verb@    char c;@\\
\mbox{}\verb@    Manager reader;@\\
\mbox{}\verb@    Goto_Node *state = NULL;@\\
\mbox{}\verb@    reader.prev = NULL;@\\
\mbox{}\verb@    reader.scrap = scrap_array(i).slab;@\\
\mbox{}\verb@    reader.index = 0;@\\
\mbox{}\verb@    c = pop(&reader);@\\
\mbox{}\verb@    while (c) {@\\
\mbox{}\verb@      while (state && !goto_lookup(c, state))@\\
\mbox{}\verb@        state = state->fail;@\\
\mbox{}\verb@      if (state)@\\
\mbox{}\verb@        state = goto_lookup(c, state);@\\
\mbox{}\verb@      else@\\
\mbox{}\verb@        state = root[c];@\\
\mbox{}\verb@      c = pop(&reader);@\\
\mbox{}\verb@      if (state && state->output) {@\\
\mbox{}\verb@        Name_Node *p = state->output;@\\
\mbox{}\verb@        do {@\\
\mbox{}\verb@          Name *name = p->name;@\\
\mbox{}\verb@          if (!reject_match(name, c, &reader) &&@\\
\mbox{}\verb@              (!name->uses || name->uses->scrap != i)) {@\\
\mbox{}\verb@            Scrap_Node *new_use =@\\
\mbox{}\verb@                (Scrap_Node *) arena_getmem(sizeof(Scrap_Node));@\\
\mbox{}\verb@            new_use->scrap = i;@\\
\mbox{}\verb@            new_use->next = name->uses;@\\
\mbox{}\verb@            name->uses = new_use;@\\
\mbox{}\verb@          }@\\
\mbox{}\verb@          p = p->next;@\\
\mbox{}\verb@        } while (p);@\\
\mbox{}\verb@      }@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 65a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsubsection{Rejecting Matches}

A problem with simple substring matching is that the string ``he''
would match longer strings like ``she'' and ``her.'' Norman Ramsey
suggested examining the characters occurring immediately before and
after a match and rejecting the match if it appears to be part of a
longer token. Of course, the concept of {\sl token\/} is
language-dependent, so we may be occasionally mistaken.
For the present, we'll consider the mechanism an experiment.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap179}
\verb@"scraps.c"@ {\footnotesize 69a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@#define sym_char(c) (isalnum(c) || (c) == '_')@\\
\mbox{}\verb@@\\
\mbox{}\verb@static int op_char(c)@\\
\mbox{}\verb@     char c;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  switch (c) {@\\
\mbox{}\verb@    case '!': case '@{\tt @}\verb@': case '#': case '%': case '$': case '^': @\\
\mbox{}\verb@    case '&': case '*': case '-': case '+': case '=': case '/':@\\
\mbox{}\verb@    case '|': case '~': case '<': case '>':@\\
\mbox{}\verb@      return TRUE;@\\
\mbox{}\verb@    default:@\\
\mbox{}\verb@      return FALSE;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap180}
\verb@"scraps.c"@ {\footnotesize 69b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static int reject_match(name, post, reader)@\\
\mbox{}\verb@     Name *name;@\\
\mbox{}\verb@     char post;@\\
\mbox{}\verb@     Manager *reader;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  int len = strlen(name->spelling);@\\
\mbox{}\verb@  char first = name->spelling[0];@\\
\mbox{}\verb@  char last = name->spelling[len - 1];@\\
\mbox{}\verb@  char prev = '\0';@\\
\mbox{}\verb@  len = reader->index - len - 2;@\\
\mbox{}\verb@  if (len >= 0)@\\
\mbox{}\verb@    prev = reader->scrap->chars[len];@\\
\mbox{}\verb@  else if (reader->prev)@\\
\mbox{}\verb@    prev = reader->scrap->chars[SLAB_SIZE - len];@\\
\mbox{}\verb@  if (sym_char(last) && sym_char(post)) return TRUE;@\\
\mbox{}\verb@  if (sym_char(first) && sym_char(prev)) return TRUE;@\\
\mbox{}\verb@  if (op_char(last) && op_char(post)) return TRUE;@\\
\mbox{}\verb@  if (op_char(first) && op_char(prev)) return TRUE;@\\
\mbox{}\verb@  return FALSE;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\section{Memory Management} \label{memory-management}

I manage memory using a simple scheme inspired by Hanson's idea of
{\em arenas\/}~\cite{hanson:90}.
Basically, I allocate all the storage required when processing a
source file (primarily for names and scraps) using calls to 
\verb|arena_getmem(n)|, where \verb|n| specifies the number of bytes to
be allocated. When the storage is no longer required, the entire arena
is freed with a single call to  \verb|arena_free()|. Both operations
are quite fast.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap181}
$\langle$Function prototypes {\footnotesize 69c}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@extern void *arena_getmem();@\\
\mbox{}\verb@extern void arena_free();@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro defined by scraps 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c.
\item Macro referenced in scrap 7a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap182}
\verb@"arena.c"@ {\footnotesize 70a }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@typedef struct chunk {@\\
\mbox{}\verb@  struct chunk *next;@\\
\mbox{}\verb@  char *limit;@\\
\mbox{}\verb@  char *avail;@\\
\mbox{}\verb@} Chunk;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9d, 70abc, 71c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
We define an empty chunk called \verb|first|. The variable \verb|arena| points
at the current chunk of memory; it's initially pointed at \verb|first|.
As soon as some storage is required, a ``real'' chunk of memory will
be allocated and attached to \verb|first->next|; storage will be
allocated from the new chunk (and later chunks if necessary).
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap183}
\verb@"arena.c"@ {\footnotesize 70b }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@static Chunk first = { NULL, NULL, NULL };@\\
\mbox{}\verb@static Chunk *arena = &first;@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9d, 70abc, 71c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Allocating Memory}

The routine \verb|arena_getmem(n)| returns a pointer to (at least) 
\verb|n| bytes of memory. Note that \verb|n| is rounded up to ensure
that returned pointers are always aligned.  We align to the nearest
8~byte segment, since that'll satisfy the more common 2-byte and
4-byte alignment restrictions too.

\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap184}
\verb@"arena.c"@ {\footnotesize 70c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void *arena_getmem(n)@\\
\mbox{}\verb@     size_t n;@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  char *q;@\\
\mbox{}\verb@  char *p = arena->avail;@\\
\mbox{}\verb@  n = (n + 7) & ~7;             /* ensuring alignment to 8 bytes */@\\
\mbox{}\verb@  q = p + n;@\\
\mbox{}\verb@  if (q <= arena->limit) {@\\
\mbox{}\verb@    arena->avail = q;@\\
\mbox{}\verb@    return p;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Find a new chunk of memory {\footnotesize 71a}$\rangle$\verb@@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9d, 70abc, 71c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
If the current chunk doesn't have adequate space (at least \verb|n|
bytes) we examine the rest of the list of chunks (starting at 
\verb|arena->next|) looking for a chunk with adequate space. If \verb|n|
is very large, we may not find it right away or we may not find a
suitable chunk at all.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap185}
$\langle$Find a new chunk of memory {\footnotesize 71a}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  Chunk *ap = arena;@\\
\mbox{}\verb@  Chunk *np = ap->next;@\\
\mbox{}\verb@  while (np) {@\\
\mbox{}\verb@    char *v = sizeof(Chunk) + (char *) np;@\\
\mbox{}\verb@    if (v + n <= np->limit) {@\\
\mbox{}\verb@      np->avail = v + n;@\\
\mbox{}\verb@      arena = np;@\\
\mbox{}\verb@      return v;@\\
\mbox{}\verb@    }@\\
\mbox{}\verb@    ap = np;@\\
\mbox{}\verb@    np = ap->next;@\\
\mbox{}\verb@  }@\\
\mbox{}\verb@  @$\langle$Allocate a new chunk of memory {\footnotesize 71b}$\rangle$\verb@@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 70c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
If there isn't a suitable chunk of memory on the free list, then we
need to allocate a new one.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap186}
$\langle$Allocate a new chunk of memory {\footnotesize 71b}$\rangle\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@{@\\
\mbox{}\verb@  size_t m = n + 10000;@\\
\mbox{}\verb@  np = (Chunk *) malloc(m);@\\
\mbox{}\verb@  np->limit = m + (char *) np;@\\
\mbox{}\verb@  np->avail = n + sizeof(Chunk) + (char *) np;@\\
\mbox{}\verb@  np->next = NULL;@\\
\mbox{}\verb@  ap->next = np;@\\
\mbox{}\verb@  arena = np;@\\
\mbox{}\verb@  return sizeof(Chunk) + (char *) np;@\\
\mbox{}\verb@}@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item Macro referenced in scrap 71a.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\subsection{Freeing Memory}

To free all the memory in the arena, we need only point \verb|arena|
back to the first empty chunk.
\begin{flushleft} \small
\begin{minipage}{\linewidth} \label{scrap187}
\verb@"arena.c"@ {\footnotesize 71c }$\equiv$
\vspace{-1ex}
\begin{list}{}{} \item
\mbox{}\verb@void arena_free()@\\
\mbox{}\verb@{@\\
\mbox{}\verb@  arena = &first;@\\
\mbox{}\verb@}@\\
\mbox{}\verb@@$\Diamond$
\end{list}
\vspace{-1ex}
\footnotesize\addtolength{\baselineskip}{-1ex}
\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item File defined by scraps 9d, 70abc, 71c.
\end{list}
\end{minipage}\\[4ex]
\end{flushleft}
\chapter{Indices} \label{indices}

Three sets of indices can be created automatically: an index of file
names, an index of macro names, and an index of user-specified
identifiers. An index entry includes the name of the entry, where it
was defined, and where it was referenced.

\section{Files}


{\small\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item \verb@"arena.c"@ {\footnotesize Defined by scraps 9d, 70abc, 71c.
}
\item \verb@"global.c"@ {\footnotesize Defined by scrap 9e.}
\item \verb@"global.h"@ {\footnotesize Defined by scrap 7a.}
\item \verb@"html.c"@ {\footnotesize Defined by scraps 8e, 28ab, 32abc, 33a, 35a, 36c.
}
\item \verb@"input.c"@ {\footnotesize Defined by scraps 9a, 39d, 40ab, 42c.
}
\item \verb@"latex.c"@ {\footnotesize Defined by scraps 8d, 16d, 17a, 21b, 22a, 24b, 26b.
}
\item \verb@"main.c"@ {\footnotesize Defined by scraps 8b, 9f.
}
\item \verb@"names.c"@ {\footnotesize Defined by scraps 9c, 54ab, 55a, 56, 57ab, 58b, 60a, 62a, 63ab.
}
\item \verb@"output.c"@ {\footnotesize Defined by scraps 8f, 37c.
}
\item \verb@"pass1.c"@ {\footnotesize Defined by scraps 8c, 14b.
}
\item \verb@"scraps.c"@ {\footnotesize Defined by scraps 9b, 43abce, 44ab, 45bcde, 48bc, 49b, 52a, 63c, 64abcd, 65ab, 69ab.
}
\end{list}}

\section{Macros}


{\small\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item $\langle$Accumulate scrap and return \verb|scraps++| {\footnotesize 46b}$\rangle$ {\footnotesize Referenced in scrap 45e.}
\item $\langle$Add \verb|scrap| to \verb|name|'s definition list {\footnotesize 16a}$\rangle$ {\footnotesize Referenced in scraps 15bc.
}
\item $\langle$Add current scrap to \verb|name|'s uses {\footnotesize 48a}$\rangle$ {\footnotesize Referenced in scrap 47b.}
\item $\langle$Add letters to scraps with duplicate page numbers {\footnotesize 52b}$\rangle$ {\footnotesize Referenced in scrap 52a.}
\item $\langle$Allocate a new chunk of memory {\footnotesize 71b}$\rangle$ {\footnotesize Referenced in scrap 71a.}
\item $\langle$Begin HTML scrap environment {\footnotesize 30e}$\rangle$ {\footnotesize Referenced in scraps 30ac.
}
\item $\langle$Begin the scrap environment {\footnotesize 19c}$\rangle$ {\footnotesize Referenced in scraps 19ab.
}
\item $\langle$Build \verb|source_name| and \verb|tex_name| {\footnotesize 12b}$\rangle$ {\footnotesize Referenced in scrap 12a.}
\item $\langle$Build failure functions {\footnotesize 67}$\rangle$ {\footnotesize Referenced in scrap 65a.}
\item $\langle$Build macro definition {\footnotesize 15c}$\rangle$ {\footnotesize Referenced in scrap 15a.}
\item $\langle$Build output file definition {\footnotesize 15b}$\rangle$ {\footnotesize Referenced in scrap 15a.}
\item $\langle$Check HTML at-sequence for end-of-scrap {\footnotesize 33b}$\rangle$ {\footnotesize Referenced in scrap 33a.}
\item $\langle$Check at-sequence for end-of-scrap {\footnotesize 22c}$\rangle$ {\footnotesize Referenced in scrap 22a.}
\item $\langle$Check for ambiguous prefix {\footnotesize 55b}$\rangle$ {\footnotesize Referenced in scrap 55a.}
\item $\langle$Check for end of scrap name and return {\footnotesize 49a}$\rangle$ {\footnotesize Referenced in scrap 48c.}
\item $\langle$Check for macro invocation in scrap {\footnotesize 51b}$\rangle$ {\footnotesize Referenced in scrap 50a.}
\item $\langle$Check for terminating at-sequence and return name {\footnotesize 60b}$\rangle$ {\footnotesize Referenced in scrap 60a.}
\item $\langle$Cleanup and install name {\footnotesize 61a}$\rangle$ {\footnotesize Referenced in scraps 60b, 61b, 62b.
}
\item $\langle$Collect include-file name {\footnotesize 42a}$\rangle$ {\footnotesize Referenced in scrap 41b.}
\item $\langle$Collect user-specified index entries {\footnotesize 47a}$\rangle$ {\footnotesize Referenced in scrap 46c.}
\item $\langle$Compare the temp file and the old file {\footnotesize 38b}$\rangle$ {\footnotesize Referenced in scrap 38a.}
\item $\langle$Copy \verb|defs->scrap| to \verb|file| {\footnotesize 50a}$\rangle$ {\footnotesize Referenced in scrap 49b.}
\item $\langle$Copy \verb|source_file| into \verb|html_file| {\footnotesize 28c}$\rangle$ {\footnotesize Referenced in scrap 28b.}
\item $\langle$Copy \verb|source_file| into \verb|tex_file| {\footnotesize 17b}$\rangle$ {\footnotesize Referenced in scrap 17a.}
\item $\langle$Copy macro into \verb|file| {\footnotesize 51c}$\rangle$ {\footnotesize Referenced in scrap 51b.}
\item $\langle$Create new name entry {\footnotesize 58a}$\rangle$ {\footnotesize Referenced in scraps 55a, 57b.
}
\item $\langle$Create new scrap, managed by \verb|writer| {\footnotesize 46a}$\rangle$ {\footnotesize Referenced in scrap 45e.}
\item $\langle$Expand tab into spaces {\footnotesize 22b}$\rangle$ {\footnotesize Referenced in scraps 22a, 33a, 51a.
}
\item $\langle$Extend goto graph with \verb|tree->spelling| {\footnotesize 66}$\rangle$ {\footnotesize Referenced in scrap 65b.}
\item $\langle$Fill in the middle of HTML scrap environment {\footnotesize 31a}$\rangle$ {\footnotesize Referenced in scraps 30ac.
}
\item $\langle$Fill in the middle of the scrap environment {\footnotesize 19d}$\rangle$ {\footnotesize Referenced in scraps 19ab.
}
\item $\langle$Find a new chunk of memory {\footnotesize 71a}$\rangle$ {\footnotesize Referenced in scrap 70c.}
\item $\langle$Finish HTML scrap environment {\footnotesize 31b}$\rangle$ {\footnotesize Referenced in scraps 30ac.
}
\item $\langle$Finish the scrap environment {\footnotesize 20a}$\rangle$ {\footnotesize Referenced in scraps 19ab.
}
\item $\langle$Format HTML macro name {\footnotesize 34a}$\rangle$ {\footnotesize Referenced in scrap 33b.}
\item $\langle$Format a user HTML index entry {\footnotesize 37a}$\rangle$ {\footnotesize Referenced in scrap 36c.}
\item $\langle$Format a user index entry {\footnotesize 27a}$\rangle$ {\footnotesize Referenced in scrap 26b.}
\item $\langle$Format an HTML index entry {\footnotesize 35b}$\rangle$ {\footnotesize Referenced in scrap 35a.}
\item $\langle$Format an index entry {\footnotesize 24c}$\rangle$ {\footnotesize Referenced in scrap 24b.}
\item $\langle$Format macro name {\footnotesize 23b}$\rangle$ {\footnotesize Referenced in scrap 22c.}
\item $\langle$Function prototypes {\footnotesize 14a, 16c, 27b, 37b, 39a, 43d, 51d, 53d, 64e, 69c}$\rangle$ {\footnotesize Referenced in scrap 7a.}
\item $\langle$Global variable declarations {\footnotesize 10ac, 39b, 44d, 53b}$\rangle$ {\footnotesize Referenced in scrap 7a.}
\item $\langle$Global variable definitions {\footnotesize 10bd, 39c, 45a, 53c}$\rangle$ {\footnotesize Referenced in scrap 9e.}
\item $\langle$Handle \verb|EOF| {\footnotesize 42b}$\rangle$ {\footnotesize Referenced in scrap 40b.}
\item $\langle$Handle an ``at'' character {\footnotesize 41a}$\rangle$ {\footnotesize Referenced in scrap 40b.}
\item $\langle$Handle at-sign during scrap accumulation {\footnotesize 46c}$\rangle$ {\footnotesize Referenced in scrap 46b.}
\item $\langle$Handle macro invocation in scrap {\footnotesize 47b}$\rangle$ {\footnotesize Referenced in scrap 46c.}
\item $\langle$Handle optional per-file flags {\footnotesize 59}$\rangle$ {\footnotesize Referenced in scrap 58b.}
\item $\langle$Handle tab characters on output {\footnotesize 51a}$\rangle$ {\footnotesize Referenced in scrap 50a.}
\item $\langle$Handle the file name in \verb|argv[arg]| {\footnotesize 12a}$\rangle$ {\footnotesize Referenced in scrap 11c.}
\item $\langle$Include files {\footnotesize 7b}$\rangle$ {\footnotesize Referenced in scrap 7a.}
\item $\langle$Insert appropriate indentation {\footnotesize 50c}$\rangle$ {\footnotesize Referenced in scraps 50ab.
}
\item $\langle$Insert debugging information if required {\footnotesize 50b}$\rangle$ {\footnotesize Referenced in scraps 50a, 51b.
}
\item $\langle$Interpret HTML at-sequence {\footnotesize 29}$\rangle$ {\footnotesize Referenced in scrap 28c.}
\item $\langle$Interpret at-sequence {\footnotesize 18}$\rangle$ {\footnotesize Referenced in scrap 17b.}
\item $\langle$Interpret command-line arguments {\footnotesize 10e, 11a}$\rangle$ {\footnotesize Referenced in scrap 9f.}
\item $\langle$Interpret the argument string \verb|s| {\footnotesize 11b}$\rangle$ {\footnotesize Referenced in scrap 11a.}
\item $\langle$Look for end of scrap name and return {\footnotesize 62b}$\rangle$ {\footnotesize Referenced in scrap 62a.}
\item $\langle$Open an include file {\footnotesize 41b}$\rangle$ {\footnotesize Referenced in scrap 41a.}
\item $\langle$Process a file {\footnotesize 13}$\rangle$ {\footnotesize Referenced in scrap 12a.}
\item $\langle$Process the remaining arguments (file names) {\footnotesize 11c}$\rangle$ {\footnotesize Referenced in scrap 9f.}
\item $\langle$Reverse cross-reference lists {\footnotesize 16b}$\rangle$ {\footnotesize Referenced in scrap 14b.}
\item $\langle$Save macro name {\footnotesize 47c}$\rangle$ {\footnotesize Referenced in scrap 47b.}
\item $\langle$Scan at-sequence {\footnotesize 15a}$\rangle$ {\footnotesize Referenced in scrap 14c.}
\item $\langle$Scan the source file, looking for at-sequences {\footnotesize 14c}$\rangle$ {\footnotesize Referenced in scrap 14b.}
\item $\langle$Search scraps {\footnotesize 68}$\rangle$ {\footnotesize Referenced in scrap 65a.}
\item $\langle$Skip over index entries {\footnotesize 23a}$\rangle$ {\footnotesize Referenced in scraps 22c, 33b.
}
\item $\langle$Skip until scrap begins, then return name {\footnotesize 61b}$\rangle$ {\footnotesize Referenced in scrap 60a.}
\item $\langle$Type declarations {\footnotesize 8a, 52c, 53a}$\rangle$ {\footnotesize Referenced in scrap 7a.}
\item $\langle$Warn (only once) about needing to rerun after Latex {\footnotesize 44c}$\rangle$ {\footnotesize Referenced in scraps 44a, 52a.
}
\item $\langle$Write HTML abbreviated definition list {\footnotesize 34b}$\rangle$ {\footnotesize Referenced in scrap 34a.}
\item $\langle$Write HTML defining scrap numbers {\footnotesize 35d}$\rangle$ {\footnotesize Referenced in scrap 35b.}
\item $\langle$Write HTML file defs {\footnotesize 31c}$\rangle$ {\footnotesize Referenced in scrap 30a.}
\item $\langle$Write HTML file's defining scrap numbers {\footnotesize 35c}$\rangle$ {\footnotesize Referenced in scrap 35b.}
\item $\langle$Write HTML index of file names {\footnotesize 34c}$\rangle$ {\footnotesize Referenced in scrap 29.}
\item $\langle$Write HTML index of macro names {\footnotesize 34d}$\rangle$ {\footnotesize Referenced in scrap 29.}
\item $\langle$Write HTML index of user-specified names {\footnotesize 36b}$\rangle$ {\footnotesize Referenced in scrap 29.}
\item $\langle$Write HTML macro declaration {\footnotesize 30d}$\rangle$ {\footnotesize Referenced in scrap 30c.}
\item $\langle$Write HTML macro definition {\footnotesize 30c}$\rangle$ {\footnotesize Referenced in scrap 29.}
\item $\langle$Write HTML macro defs {\footnotesize 31d}$\rangle$ {\footnotesize Referenced in scrap 30c.}
\item $\langle$Write HTML macro refs {\footnotesize 31e}$\rangle$ {\footnotesize Referenced in scrap 30c.}
\item $\langle$Write HTML output file declaration {\footnotesize 30b}$\rangle$ {\footnotesize Referenced in scrap 30a.}
\item $\langle$Write HTML output file definition {\footnotesize 30a}$\rangle$ {\footnotesize Referenced in scrap 29.}
\item $\langle$Write HTML referencing scrap numbers {\footnotesize 36a}$\rangle$ {\footnotesize Referenced in scrap 35b.}
\item $\langle$Write abbreviated definition list {\footnotesize 23c}$\rangle$ {\footnotesize Referenced in scrap 23b.}
\item $\langle$Write defining scrap numbers {\footnotesize 25b}$\rangle$ {\footnotesize Referenced in scrap 24c.}
\item $\langle$Write file defs {\footnotesize 20b}$\rangle$ {\footnotesize Referenced in scrap 19a.}
\item $\langle$Write file's defining scrap numbers {\footnotesize 25a}$\rangle$ {\footnotesize Referenced in scrap 24c.}
\item $\langle$Write index of file names {\footnotesize 23d}$\rangle$ {\footnotesize Referenced in scrap 18.}
\item $\langle$Write index of macro names {\footnotesize 24a}$\rangle$ {\footnotesize Referenced in scrap 18.}
\item $\langle$Write index of user-specified names {\footnotesize 26a}$\rangle$ {\footnotesize Referenced in scrap 18.}
\item $\langle$Write macro definition {\footnotesize 19b}$\rangle$ {\footnotesize Referenced in scrap 18.}
\item $\langle$Write macro defs {\footnotesize 20c}$\rangle$ {\footnotesize Referenced in scrap 19b.}
\item $\langle$Write macro refs {\footnotesize 21a}$\rangle$ {\footnotesize Referenced in scrap 19b.}
\item $\langle$Write out \verb|files->spelling| {\footnotesize 38a}$\rangle$ {\footnotesize Referenced in scrap 37c.}
\item $\langle$Write output file definition {\footnotesize 19a}$\rangle$ {\footnotesize Referenced in scrap 18.}
\item $\langle$Write referencing scrap numbers {\footnotesize 25c}$\rangle$ {\footnotesize Referenced in scrap 24c.}
\end{list}}

\section{Identifiers}

Knuth prints his index of identifiers in a two-column format.
I could force this automatically by emitting the \verb|\twocolumn|
command; but this has the side effect of forcing a new page.
Therefore, it seems better to leave it this up to the user.


{\small\begin{list}{}{\setlength{\itemsep}{-\parsep}\setlength{\itemindent}{-\leftmargin}}
\item \verb@already_warned@: 44c, \underline{44d}, 45a, 52a.
\item \verb@arena@: \underline{70b}, 70c, 71abc.
\item \verb@arena_free@: 13, 69c, \underline{71c}.
\item \verb@arena_getmem@: 16a, 43e, 45c, 46a, 47a, 48a, 54b, 58a, 65a, 66, 67, 68, 69c, \underline{70c}.
\item \verb@build_gotos@: 65a, \underline{65b}.
\item \verb@Chunk@: \underline{70a}, 70b, 71ab.
\item \verb@collect_file_name@: 15b, 19a, 30a, 53d, \underline{58b}.
\item \verb@collect_macro_name@: 15c, 19b, 30c, 53d, \underline{60a}.
\item \verb@collect_numbers@: 13, 51d, \underline{52a}.
\item \verb@collect_scrap@: 15bc, 43d, \underline{45e}.
\item \verb@collect_scrap_name@: 23b, 34a, 47b, 53d, \underline{62a}.
\item \verb@command_name@: \underline{10c}, 10de, 11bc, 15a, 17a, 21a, 23b, 28b, 31e, 34a, 38a, 41ab, 42ac, 44c, 46bc, 47a, 49a, 51c, 55b, 58b, 59, 60ab, 61ab, 62ab.
\item \verb@compare@: \underline{54a}, 55a, 56.
\item \verb@compare_flag@: \underline{10a}, 10b, 11b, 38a.
\item \verb@copy_scrap@: 16d, 19d, \underline{22a}, 28a, 31a, \underline{33a}.
\item \verb@depths@: \underline{64c}, 65a, 66, 67.
\item \verb@display_scrap_numbers@: 28a, \underline{32b}, 32c, 35d.
\item \verb@display_scrap_ref@: 28a, \underline{32a}, 32b, 34b, 37a.
\item \verb@double_at@: \underline{39d}, 41a, 42c.
\item \verb@EQUAL@: \underline{54a}, 55a, 56.
\item \verb@exit@: \underline{7b}, 9f, 11c, 38a, 41ab, 42ac, 46bc, 47a, 49a, 51c, 58b, 60ab, 61ab, 62ab.
\item \verb@EXTENSION@: \underline{54a}, 55a, 56.
\item \verb@FALSE@: \underline{8a}, 10ab, 11b, 18, 21b, 24a, 25b, 27a, 34d, 41a, 42c, 51c, 52a, 56, 58a, 59, 69ab.
\item \verb@fclose@: \underline{7b}, 17a, 28b, 38ab, 42b, 52a.
\item \verb@FILE@: \underline{7b}, 17a, 21b, 22a, 24b, 26b, 28b, 32abc, 33a, 35a, 36c, 38ab, 39d, 40a, 44ab, 49b, 52a.
\item \verb@file_names@: 13, 14b, 16b, 23d, 34c, \underline{53b}, 53c, 58b.
\item \verb@first@: 44a, 69b, \underline{70b}, 71c.
\item \verb@fopen@: \underline{7b}, 17a, 28b, 38ab, 41b, 42c, 52a.
\item \verb@format_entry@: 16d, 23d, 24a, \underline{24b}, 28a, 34cd, \underline{35a}.
\item \verb@format_user_entry@: 16d, 26a, \underline{26b}, 28a, 36b, \underline{36c}.
\item \verb@fprintf@: \underline{7b}, 11bc, 14b, 15a, 17a, 19abc, 21a, 23b, 24c, 27a, 28b, 30bd, 31e, 34a, 35b, 37a, 38a, 41ab, 42ac, 44ac, 46bc, 47a, 49a, 50b, 51c, 55b, 58b, 59, 60ab, 61ab, 62ab.
\item \verb@fputs@: \underline{7b}, 19abcd, 20abc, 21ab, 22ac, 23bcd, 24ac, 25ac, 26a, 27a, 30bde, 31abcde, 32abc, 33a, 34abcd, 35bc, 36ab, 37a, 44a.
\item \verb@getc@: \underline{7b}, 38b, 40b, 41ab, 42abc.
\item \verb@goto_lookup@: \underline{64d}, 66, 67, 68.
\item \verb@Goto_Node@: \underline{64a}, 64bcd, 65a, 66, 67, 68.
\item \verb@GREATER@: \underline{54a}, 55a, 56.
\item \verb@html_flag@: \underline{10a}, 10b, 12b, 13.
\item \verb@include_depth@: \underline{39d}, 41b, 42bc.
\item \verb@init_scraps@: 14b, 43d, \underline{43e}.
\item \verb@isgraph@: \underline{7b}, 42a, 58b, 62a.
\item \verb@islower@: \underline{7b}, 57a.
\item \verb@isspace@: \underline{7b}, 20a, 47a, 58b, 59, 60a, 61b.
\item \verb@isupper@: \underline{7b}, 57a.
\item \verb@LESS@: \underline{54a}, 55a, 56.
\item \verb@macro_names@: 14b, 16b, 24a, 34d, 49a, \underline{53b}, 53c, 61a.
\item \verb@main@: \underline{9f}.
\item \verb@malloc@: \underline{7b}, 71b.
\item \verb@Manager@: \underline{45b}, 45cde, 48bc, 50a, 68, 69b.
\item \verb@max_depth@: \underline{64c}, 65a, 66, 67.
\item \verb@Move_Node@: \underline{64b}, 64d, 66, 67.
\item \verb@Name@: 15bc, 19ab, 23b, 24b, 26b, 30ac, 34a, 35a, 36c, 37c, 47ab, 48c, 51c, \underline{53a}, 53bcd, 55a, 56, 57b, 58ab, 60a, 62a, 63ac, 65b, 68, 69b.
\item \verb@name_add@: 47a, 53d, \underline{57b}, 58b.
\item \verb@Name_Node@: \underline{63c}, 64a, 66, 67, 68.
\item \verb@number_flag@: \underline{10a}, 10b, 11b, 13, 52a.
\item \verb@op_char@: \underline{69a}, 69b.
\item \verb@output_flag@: \underline{10a}, 10b, 11b, 13.
\item \verb@pass1@: 13, 14a, \underline{14b}, 22c, 33b.
\item \verb@pop@: \underline{48b}, 48c, 49a, 50a, 51b, 68.
\item \verb@pop_scrap_name@: \underline{48c}, 51c.
\item \verb@PREFIX@: \underline{54a}, 55a, 56.
\item \verb@prefix_add@: 49a, 53d, \underline{55a}, 61a.
\item \verb@print_scrap_numbers@: 16d, 20bc, 21a, \underline{21b}, 25ac, 28a, 31cde, \underline{32c}, 35c, 36a.
\item \verb@push@: \underline{45c}, 45d, 46bc, 47c.
\item \verb@pushs@: \underline{45d}, 46c, 47c.
\item \verb@putc@: \underline{7b}, 17b, 18, 22abc, 23b, 24c, 25abc, 27a, 28c, 29, 33a, 34a, 35bd, 44a, 50ac, 51ab.
\item \verb@reject_match@: 65a, 68, \underline{69b}.
\item \verb@remove@: \underline{7b}, 38ab.
\item \verb@reverse@: 63a, \underline{63b}.
\item \verb@reverse_lists@: 16b, 53d, \underline{63a}.
\item \verb@robs_strcmp@: \underline{57a}, 57b.
\item \verb@root@: 55a, 57b, 58a, \underline{64c}, 65a, 66, 67, 68.
\item \verb@save_string@: 41b, 46a, 53d, \underline{54b}, 55a, 58a.
\item \verb@SCRAP@: \underline{43c}, 43e, 46a.
\item \verb@ScrapEntry@: \underline{43b}, 43ce, 46a.
\item \verb@scraps@: 10a, 17b, 19abc, 20bc, 21ab, 28c, 30abcd, 32bc, \underline{43c}, 43e, 45e, 46abc, 47a, 48a, 52ab, 65a, 68.
\item \verb@scrap_array@: \underline{43c}, 44a, 46ab, 50ab, 52ab, 68.
\item \verb@Scrap_Node@: 16a, 21b, 23c, 25abc, 27a, 32bc, 34b, 36a, 37a, 47a, 48a, 49b, \underline{52c}, 53a, 63ab, 68.
\item \verb@search@: 14b, 64e, \underline{65a}.
\item \verb@size_t@: \underline{7b}, 70c, 71b.
\item \verb@Slab@: \underline{43a}, 43b, 45bc, 46a, 48b.
\item \verb@SLAB_SIZE@: \underline{43a}, 45c, 48b, 69b.
\item \verb@source_file@: 17a, 28b, \underline{39d}, 40b, 41ab, 42abc.
\item \verb@source_get@: 14c, 15a, 17b, 18, 20a, 22ac, 23ad, 24a, 26a, 28c, 29, 31b, 33ab, 34cd, 36b, 39a, \underline{40b}, 41b, 42b, 46bc, 47ab, 58b, 59, 60ab, 61b, 62ab.
\item \verb@source_line@: 15a, \underline{39b}, 39c, 40b, 41ab, 42abc, 46ac, 47a, 55b, 58b, 59, 60a, 61a, 62ab.
\item \verb@source_name@: 12ab, 13, 15a, \underline{39b}, 39c, 41ab, 42abc, 46ac, 47a, 55b, 58b, 59, 60ab, 61ab, 62ab.
\item \verb@source_open@: 14b, 17a, 28b, 39a, \underline{42c}.
\item \verb@source_peek@: \underline{39d}, 40b, 41ab, 42bc.
\item \verb@stack@: \underline{40a}, 41b, 42b.
\item \verb@stderr@: \underline{7b}, 11bc, 14b, 15a, 17a, 21a, 23b, 28b, 31e, 34a, 38a, 41ab, 42ac, 44c, 46bc, 47a, 49a, 51c, 55b, 58b, 59, 60ab, 61ab, 62ab.
\item \verb@strlen@: \underline{7b}, 47c, 54ab, 69b.
\item \verb@sym_char@: \underline{69a}, 69b.
\item \verb@tempnam@: \underline{7b}, 38a.
\item \verb@tex_flag@: \underline{10a}, 10b, 11b, 13, 14b, 51c.
\item \verb@toupper@: \underline{7b}, 57a.
\item \verb@TRUE@: \underline{8a}, 10ab, 11b, 13, 18, 21b, 23d, 25b, 27a, 34c, 41a, 44bc, 48c, 51c, 56, 58a, 59, 69ab.
\item \verb@user_names@: 14b, 16b, 26a, 36b, 47a, \underline{53b}, 53c, 65a.
\item \verb@verbose_flag@: \underline{10a}, 10b, 11b, 14b, 17a, 28b, 38a.
\item \verb@write_files@: 13, 37b, \underline{37c}.
\item \verb@write_html@: 13, 27b, \underline{28b}.
\item \verb@write_scraps@: 38a, 43d, \underline{49b}, 51c.
\item \verb@write_scrap_ref@: 21b, 25b, 27a, 43d, \underline{44a}, 44b.
\item \verb@write_single_scrap_ref@: 19ab, 21a, 23c, 25ac, 27a, 30bd, 32a, 43d, \underline{44b}.
\item \verb@write_tex@: 13, 16c, \underline{17a}.
\end{list}}

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