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[anag] / anag.c
1 /* -*-c-*-
2 *
3 * $Id: anag.c,v 1.5 2002/08/11 12:58:09 mdw Exp $
4 *
5 * Main driver for anag
6 *
7 * (c) 2001 Mark Wooding
8 */
9
10 /*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Anag: a simple wordgame helper.
13 *
14 * Anag is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * Anag is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with Anag; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 */
28
29 /*----- Revision history --------------------------------------------------*
30 *
31 * $Log: anag.c,v $
32 * Revision 1.5 2002/08/11 12:58:09 mdw
33 * Added support for regular expression matching, if supported by the C
34 * library.
35 *
36 * Revision 1.4 2001/02/19 19:18:50 mdw
37 * Minor big fixes to parser.
38 *
39 * Revision 1.3 2001/02/16 21:45:19 mdw
40 * Be more helpful. Improve full help message. Special-case error for
41 * empty command strings.
42 *
43 * Revision 1.2 2001/02/07 09:09:11 mdw
44 * Fix spurious error when `-file' is used.
45 *
46 * Revision 1.1 2001/02/04 17:14:42 mdw
47 * Initial checkin
48 *
49 */
50
51 /*----- Header files ------------------------------------------------------*/
52
53 #include "anag.h"
54
55 /*----- Static variables --------------------------------------------------*/
56
57 static const char *file = DICTIONARY;
58
59 /*----- Help text functions -----------------------------------------------*/
60
61 static void usage(FILE *fp)
62 {
63 pquis(fp, "Usage: $ [-f file] expression\n");
64 }
65
66 static void version(FILE *fp)
67 {
68 pquis(fp, "$, version " VERSION "\n");
69 }
70
71 static void help(FILE *fp)
72 {
73 version(fp);
74 fputc('\n', fp);
75 usage(fp);
76 fputs("\n\
77 Searches a wordlist, printing all of the words which match an expression.\n\
78 \n\
79 Options supported are:\n\
80 \n\
81 -h, --help display this help text\n\
82 -v, --version display the program's version number\n\
83 -u, --usage display a very brief usage message\n\
84 -f, --file FILE read wordlist from FILE, not `" DICTIONARY "'\n\
85 \n\
86 The basic tests in the expression are:\n\
87 \n\
88 -anagram WORD matches a full-length anagram\n\
89 -subgram WORD matches words which only use letters in WORD\n\
90 -wildcard PATTERN matches with wildcards `*' and `?'\n\
91 -trackword WORD matches words which can be found in a trackword\n\
92 "
93 #ifdef HAVE_REGCOMP
94 "\
95 -regexp REGEXP matches with an (extended) regular expression\n\
96 "
97 #endif
98 "\
99 \n\
100 These simple tests can be combined using the operators `-a', `-o' and `-n'\n\
101 (for `and', `or' and `not'; they may also be written `&', `|' and `!' if\n\
102 you like), and grouped using parentheses `(' and `)'.\n\
103 ", fp);
104 }
105
106 /*----- The options parser ------------------------------------------------*/
107
108 /* --- Options table structure --- */
109
110 struct opt {
111 const char *name;
112 unsigned nargs;
113 unsigned f;
114 unsigned tag;
115 };
116
117 enum {
118 O_HELP, O_VERSION, O_USAGE,
119 O_FILE,
120 O_AND, O_OR, O_NOT, O_LPAREN, O_RPAREN,
121 O_ANAG, O_SUBG, O_WILD, O_TRACK, O_REGEXP,
122 O_EOF
123 };
124
125 #define OF_SHORT 1u
126
127 static const struct opt opttab[] = {
128
129 /* --- Options -- don't form part of the language --- */
130
131 { "help", 0, OF_SHORT, O_HELP },
132 { "version", 0, OF_SHORT, O_VERSION },
133 { "usage", 0, OF_SHORT, O_USAGE },
134 { "file", 1, OF_SHORT, O_FILE },
135
136 /* --- Operators -- provide the basic structure of the language --- *
137 *
138 * These are also given magical names by the parser.
139 */
140
141 { "and", 0, OF_SHORT, O_AND },
142 { "or", 0, OF_SHORT, O_OR },
143 { "not", 0, OF_SHORT, O_NOT },
144
145 /* --- Actual matching oeprations -- do something useful --- */
146
147 { "anagram", 1, 0, O_ANAG },
148 { "subgram", 1, 0, O_SUBG },
149 { "wildcard", 1, 0, O_WILD },
150 { "trackword", 1, 0, O_TRACK },
151 #ifdef HAVE_REGCOMP
152 { "regexp", 1, 0, O_REGEXP },
153 #endif
154
155 /* --- End marker --- */
156
157 { 0, 0, 0, 0 }
158 };
159
160 static int ac;
161 static const char *const *av;
162 static int ai;
163
164 /* --- @nextopt@ --- *
165 *
166 * Arguments: @const char ***arg@ = where to store the arg pointer
167 *
168 * Returns: The tag of the next option.
169 *
170 * Use: Scans the next option off the command line. If the option
171 * doesn't form part of the language, it's processed internally,
172 * and you'll never see it from here. On exit, the @arg@
173 * pointer is set to contain the address of the option scanned,
174 * followed by its arguments if any. You're expected to know
175 * how many arguments there are for your option.
176 */
177
178 static unsigned nextopt(const char *const **arg)
179 {
180 for (;;) {
181 const struct opt *o, *oo;
182 size_t sz;
183 const char *p;
184
185 /* --- Pick the next option off the front --- */
186
187 *arg = av + ai;
188 if (ai >= ac)
189 return (O_EOF);
190 p = av[ai++];
191
192 /* --- Cope with various forms of magic --- */
193
194 if (p[0] != '-') {
195 if (!p[1]) switch (*p) {
196 case '&': return (O_AND);
197 case '|': return (O_OR);
198 case '!': return (O_NOT);
199 case '(': return (O_LPAREN);
200 case ')': return (O_RPAREN);
201 }
202 goto bad;
203 }
204
205 /* --- Now cope with other sorts of weirdies --- *
206 *
207 * By the end of this, a leading `-' or `--' will have been stripped.
208 */
209
210 p++;
211 if (!*p)
212 goto bad;
213 if (*p == '-')
214 p++;
215 if (!*p) {
216 if (ai < ac)
217 die("syntax error near `--': rubbish at end of line");
218 return (O_EOF);
219 }
220
221 /* --- Now look the word up in my table --- */
222
223 sz = strlen(p);
224 oo = 0;
225 for (o = opttab; o->name; o++) {
226 if (strncmp(p, o->name, sz) == 0) {
227 if (strlen(o->name) == sz || ((o->f & OF_SHORT) && sz == 1)) {
228 oo = o;
229 break;
230 }
231 if (oo) {
232 die("ambiguous option name `-%s' (could match `-%s' or `-%s')",
233 p, oo->name, o->name);
234 }
235 oo = o;
236 }
237 }
238 if (!oo)
239 die("unrecognized option name `-%s'", p);
240
241 /* --- Sort out the arguments --- */
242
243 if (ai + oo->nargs > ac)
244 die("too few arguments for `-%s' (need %u)", oo->name, oo->nargs);
245 ai += oo->nargs;
246
247 /* --- Now process the option --- */
248
249 switch (oo->tag) {
250 case O_HELP:
251 help(stdout);
252 exit(0);
253 case O_VERSION:
254 version(stdout);
255 exit(0);
256 case O_USAGE:
257 usage(stdout);
258 exit(0);
259 case O_FILE:
260 file = (*arg)[1];
261 break;
262 default:
263 return (oo->tag);
264 }
265 continue;
266 bad:
267 die("syntax error near `%s': unknown token type", av[ai - 1]);
268 }
269 }
270
271 /*----- Node types for operators ------------------------------------------*/
272
273 /* --- Node structures --- */
274
275 typedef struct node_bin {
276 node n;
277 node *left;
278 node *right;
279 } node_bin;
280
281 typedef struct node_un {
282 node n;
283 node *arg;
284 } node_un;
285
286 /* --- Node functions --- */
287
288 static int n_or(node *nn, const char *p, size_t sz)
289 {
290 node_bin *n = (node_bin *)nn;
291 return (n->left->func(n->left, p, sz) || n->right->func(n->right, p, sz));
292 }
293
294 static int n_and(node *nn, const char *p, size_t sz)
295 {
296 node_bin *n = (node_bin *)nn;
297 return (n->left->func(n->left, p, sz) && n->right->func(n->right, p, sz));
298 }
299
300 static int n_not(node *nn, const char *p, size_t sz)
301 {
302 node_un *n = (node_un *)nn;
303 return (!n->arg->func(n->arg, p, sz));
304 }
305
306 /*----- Parser for the expression syntax ----------------------------------*/
307
308 /* --- A parser context --- */
309
310 typedef struct p_ctx {
311 unsigned t;
312 const char *const *a;
313 } p_ctx;
314
315 /* --- Parser structure --- *
316 *
317 * This is a simple recursive descent parser. The context retains
318 * information about the current token. Each function is passed the address
319 * of a node pointer to fill in. This simplifies the binary operator code
320 * somewhat, relative to returning pointers to node trees.
321 */
322
323 static void p_expr(p_ctx *p, node **/*nn*/);
324
325 static void p_next(p_ctx *p)
326 {
327 static const char *const eof[] = { "<end>", 0 };
328 p->t = nextopt(&p->a);
329 if (p->t == O_EOF)
330 p->a = eof;
331 }
332
333 static void p_factor(p_ctx *p, node **nn)
334 {
335 node_un *n;
336 if (p->t == O_LPAREN) {
337 p_next(p);
338 p_expr(p, nn);
339 if (p->t != O_RPAREN)
340 die("syntax error near `%s': missing `)'", *p->a);
341 p_next(p);
342 } else if (p->t == O_NOT) {
343 n = xmalloc(sizeof(node_un));
344 n->n.func = n_not;
345 *nn = &n->n;
346 p_next(p);
347 p_factor(p, &n->arg);
348 } else {
349 switch (p->t) {
350 case O_ANAG: *nn = anagram(p->a + 1); break;
351 case O_SUBG: *nn = subgram(p->a + 1); break;
352 case O_WILD: *nn = wildcard(p->a + 1); break;
353 case O_TRACK: *nn = trackword(p->a + 1); break;
354 #ifdef HAVE_REGCOMP
355 case O_REGEXP: *nn = regexp(p->a + 1); break;
356 #endif
357 default: die("syntax error near `%s': unexpected token", *p->a);
358 }
359 p_next(p);
360 }
361 }
362
363 static void p_term(p_ctx *p, node **nn)
364 {
365 node_bin *n;
366 for (;;) {
367 p_factor(p, nn);
368 switch (p->t) {
369 case O_AND:
370 p_next(p);
371 default:
372 break;
373 case O_RPAREN:
374 case O_OR:
375 case O_EOF:
376 return;
377 }
378 n = xmalloc(sizeof(node_bin));
379 n->left = *nn;
380 n->n.func = n_and;
381 *nn = &n->n;
382 nn = &n->right;
383 }
384 }
385
386 static void p_expr(p_ctx *p, node **nn)
387 {
388 node_bin *n;
389 for (;;) {
390 p_term(p, nn);
391 if (p->t != O_OR)
392 break;
393 p_next(p);
394 n = xmalloc(sizeof(node_bin));
395 n->left = *nn;
396 n->n.func = n_or;
397 *nn = &n->n;
398 nn = &n->right;
399 }
400 }
401
402 /* --- @p_argv@ --- *
403 *
404 * Arguments: @int argc@ = number of command-line arguments
405 * @const char *const argv[]@ = vectoor of arguments
406 *
407 * Returns: A compiled node, parsed from the arguments.
408 *
409 * Use: Does the donkey-work of parsing a command-line.
410 */
411
412 static node *p_argv(int argc, const char *const argv[])
413 {
414 p_ctx p;
415 node *n;
416
417 av = argv;
418 ac = argc;
419 ai = 1;
420 p_next(&p);
421 if (p.t == O_EOF) {
422 usage(stderr);
423 pquis(stderr, "(Run `$ --help' for more detail.)\n");
424 exit(EXIT_FAILURE);
425 }
426 p_expr(&p, &n);
427 if (p.t != O_EOF) {
428 die("syntax error near `%s': rubbish at end of line (too many `)'s?)",
429 *p.a);
430 }
431 return (n);
432 }
433
434 /*----- Main code ---------------------------------------------------------*/
435
436 /* --- @main@ --- *
437 *
438 * Arguments: @int argc@ = number of command-line arguments
439 * @char *argv[]@ = vector of argument words
440 *
441 * Returns: Zero on success, nonzero on failure.
442 *
443 * Use: Picks entries from a word list which match particular
444 * expressions. This might be of assistance to word-game types.
445 */
446
447 int main(int argc, char *argv[])
448 {
449 node *n;
450 FILE *fp;
451 dstr d = DSTR_INIT;
452 char *p, *q, *l;
453
454 ego(argv[0]);
455 n = p_argv(argc, (const char *const *)argv);
456
457 if ((fp = fopen(file, "r")) == 0)
458 die("error opening `%s': %s", file, strerror(errno));
459 for (;;) {
460 dstr_reset(&d);
461 if (dstr_putline(&d, fp) < 0)
462 break;
463 l = d.buf + d.len;
464 for (p = q = d.buf; p < l; p++) {
465 if (!isalnum((unsigned char)*p))
466 continue;
467 *q++ = tolower((unsigned char)*p);
468 }
469 *q = 0;
470 d.len = q - d.buf;
471 if (n->func(n, d.buf, d.len)) {
472 fwrite(d.buf, 1, d.len, stdout);
473 fputc('\n', stdout);
474 }
475 }
476 if (!feof(fp))
477 die("error reading `%s': %s", file, strerror(errno));
478 fclose(fp);
479 return (0);
480 }
481
482 /*----- That's all, folks -------------------------------------------------*/
Simple word-game solver