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