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args.h (4148B)
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1 /*
2
3 Simple command-line argument parser from Plan 9's u9fs:
4
5 The authors of this software are Bob Flandrena, Ken Thompson,
6 Rob Pike, and Russ Cox.
7
8 Copyright (c) 1992-2002 by Lucent Technologies.
9
10 Permission to use, copy, modify, and distribute this software for any
11 purpose without fee is hereby granted, provided that this entire notice
12 is included in all copies of any software which is or includes a copy
13 or modification of this software and in all copies of the supporting
14 documentation for such software.
15
16 THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
17 WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
18 REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
19 OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
20
21 SYNOPSIS
22 #include "args.h"
23
24 ARGBEGIN {
25 char *ARGF();
26 char *EARGF(code);
27 Rune ARGC();
28 } ARGEND
29
30 extern char *argv0;
31
32 DESCRIPTION
33 These macros assume the names argc and argv are in scope.
34 ARGBEGIN and ARGEND surround code for processing program
35 options. The code should be the cases of a C switch on option
36 characters; it is executed once for each option character.
37 Options end after an argument --, before an argument -, or
38 before an argument that doesn't begin with -.
39
40 The function macro ARGC returns the current option charac-
41 ter, as an integer.
42
43 The function macro ARGF returns the current option argument:
44 a pointer to the rest of the option string if not empty, or
45 the next argument in argv if any, or 0. ARGF must be called
46 just once for each option that takes an argument. The macro
47 EARGF is like ARGF but instead of returning zero runs code
48 and, if that returns, calls abort(). A typical value for
49 code is usage(), as in EARGF(usage()).
50
51 After ARGBEGIN, argv0 is a copy of argv[0] (conventionally
52 the name of the program).
53
54 After ARGEND, argv points at a zero-terminated list of the
55 remaining argc arguments.
56
57 EXAMPLE
58 This C program can take option b and option f, which
59 requires an argument.
60
61 void
62 main(int argc, char *argv[])
63 {
64 char *f;
65 print("%s", argv[0]);
66 ARGBEGIN {
67 case 'b':
68 print(" -b");
69 break;
70 case 'f':
71 print(" -f(%s)", (f=ARGF())? f: "no arg");
72 break;
73 default:
74 print(" badflag('%c')", ARGC());
75 } ARGEND
76 print(" %d args:", argc);
77 while(*argv)
78 print(" '%s'", *argv++);
79 print("\n");
80 exits(nil);
81 }
82
83 Here is the output from running the command
84 "prog -bffile1 -r -f file2 arg1 arg2":
85
86 prog -b -f(file1) badflag('r') -f(file2) 2 args: 'arg1' 'arg2'
87
88 */
89
90 extern const char *argv0;
91
92 #define _ARGSET(x) (x) = 0
93 #define _ARGUSED(x) if (x) { } else
94
95 #define ARGBEGIN for((argv?0:(argv=(void*)&argc)),(argv0?0:(argv0=*argv)),\
96 argv++,argc--;\
97 argv[0] && argv[0][0]=='-' && argv[0][1];\
98 argc--, argv++) {\
99 const char *_args;\
100 const char *_argt;\
101 char _argc;\
102 _args = &argv[0][1];\
103 if(_args[0]=='-' && _args[1]==0){\
104 argc--; argv++; break;\
105 }\
106 _argc = 0;\
107 while(*_args && (_argc = *_args++))\
108 switch(_argc)
109 #define ARGEND _ARGSET(_argt);_ARGUSED(_argt);_ARGUSED(_argc);_ARGUSED(_args);}_ARGUSED(argv);_ARGUSED(argc);
110 #define ARGF() (_argt=_args, _args="",\
111 (*_argt? _argt: argv[1]? (argc--, *++argv): 0))
112 #define EARGF(x) (_argt=_args, _args="",\
113 (*_argt? _argt: argv[1]? (argc--, *++argv): ((x), abort(), (char*)0)))
114
115 #define ARGC() _argc