# Oberon modules

An Oberon module is an array of 4 dictionaries: types, constants, variables and
procedures.

Modules are stored in a global dictionary keyed on their respective name.
Whenever the MODULE directive is met, we find-or-create a module of that name,
declare it the "current" module and reset the "private module".

## Current module and private module

The current module is a link to the module currently being compiled upon. All
public declarations, that is the ones with a "*", are added to one of its
dictionaries.

Parallel to it, there's the "private" module, also an array of 4 dictionaries.
All declarations are added to it. Unqualified identifier lookups are done there.
Whenever a new module is activated, we clear it.

## API

## Structs

struct Module {
  [uint,1] types constants variables procedures ;
}

Entries have these structures:

types   +00 type
consts  +00 type   +04 value
vars    +00 type   +04 address
procs   +00 sig    +04 address

## Words

activatemodule ( name -- )
  Look for name in module list. If found, activate it. Otherwise, create it and
  activate it.

curmodule ( -- module )
  Yields the currently activated module

curproc ( -- e )
  In the private module, look for the latest entry that still has a 0 addr.
  Yield the dictionary entry that corresponds to it.

curprocsig ( -- sig )
  Signature of the procedure currently being implemented.

addproc ( public? sig name -- )
  Add signature to private procs dir. If "public?" is true, also add it to the
  current module.

  Entries are added with a 0 addr. That offset it set through "implementproc".

implementcurproc ( -- )
  Set the target address of the latest proc added by "addproc" to "here".