args.h (4148B)
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