expr.y revision 9909 
1%{
2/* Written by Pace Willisson (pace@blitz.com)
3 * and placed in the public domain.
4 *
5 * Largely rewritten by J.T. Conklin (jtc@wimsey.com)
6 *
7 * $Id: expr.y,v 1.9 1995/03/19 13:28:41 joerg Exp $
8 */
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <locale.h>
14#include <ctype.h>
15#include <err.h>
16
17enum valtype {
18	integer, string
19} ;
20
21struct val {
22	enum valtype type;
23	union {
24		char *s;
25		int   i;
26	} u;
27} ;
28
29struct val *result;
30struct val *op_or ();
31struct val *op_and ();
32struct val *op_eq ();
33struct val *op_gt ();
34struct val *op_lt ();
35struct val *op_ge ();
36struct val *op_le ();
37struct val *op_ne ();
38struct val *op_plus ();
39struct val *op_minus ();
40struct val *op_times ();
41struct val *op_div ();
42struct val *op_rem ();
43struct val *op_colon ();
44
45char **av;
46%}
47
48%union
49{
50	struct val *val;
51}
52
53%left <val> '|'
54%left <val> '&'
55%left <val> '=' '>' '<' GE LE NE
56%left <val> '+' '-'
57%left <val> '*' '/' '%'
58%left <val> ':'
59%left UNARY
60
61%token <val> TOKEN
62%type <val> start expr
63
64%%
65
66start: expr { result = $$; }
67
68expr:	TOKEN
69	| '(' expr ')' { $$ = $2; }
70	| expr '|' expr { $$ = op_or ($1, $3); }
71	| expr '&' expr { $$ = op_and ($1, $3); }
72	| expr '=' expr { $$ = op_eq ($1, $3); }
73	| expr '>' expr { $$ = op_gt ($1, $3); }
74	| expr '<' expr { $$ = op_lt ($1, $3); }
75	| expr GE expr  { $$ = op_ge ($1, $3); }
76	| expr LE expr  { $$ = op_le ($1, $3); }
77	| expr NE expr  { $$ = op_ne ($1, $3); }
78	| expr '+' expr { $$ = op_plus ($1, $3); }
79	| expr '-' expr { $$ = op_minus ($1, $3); }
80	| expr '*' expr { $$ = op_times ($1, $3); }
81	| expr '/' expr { $$ = op_div ($1, $3); }
82	| expr '%' expr { $$ = op_rem ($1, $3); }
83	| expr ':' expr { $$ = op_colon ($1, $3); }
84	;
85
86
87%%
88
89struct val *
90make_integer (i)
91int i;
92{
93	struct val *vp;
94
95	vp = (struct val *) malloc (sizeof (*vp));
96	if (vp == NULL) {
97		err (2, NULL);
98	}
99
100	vp->type = integer;
101	vp->u.i  = i;
102	return vp;
103}
104
105struct val *
106make_str (s)
107char *s;
108{
109	struct val *vp;
110	int i, isint;
111
112	vp = (struct val *) malloc (sizeof (*vp));
113	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
114		err (2, NULL);
115	}
116
117	for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
118	    isint && i < strlen(s);
119	    i++)
120	{
121		if(!isdigit(s[i]))
122			 isint = 0;
123	}
124
125	vp->type = string;
126	if(isint)
127		to_integer(vp);
128
129	return vp;
130}
131
132
133void
134free_value (vp)
135struct val *vp;
136{
137	if (vp->type == string)
138		free (vp->u.s);
139}
140
141
142int
143to_integer (vp)
144struct val *vp;
145{
146	char *s;
147	int neg;
148	int i;
149
150	if (vp->type == integer)
151		return 1;
152
153	s = vp->u.s;
154	i = 0;
155
156	neg = (*s == '-');
157	if (neg)
158		s++;
159
160	for (;*s; s++) {
161		if (!isdigit (*s))
162			return 0;
163
164		i *= 10;
165		i += *s - '0';
166	}
167
168	free (vp->u.s);
169	if (neg)
170		i *= -1;
171
172	vp->type = integer;
173	vp->u.i  = i;
174	return 1;
175}
176
177void
178to_string (vp)
179struct val *vp;
180{
181	char *tmp;
182
183	if (vp->type == string)
184		return;
185
186	tmp = malloc (25);
187	if (tmp == NULL) {
188		err (2, NULL);
189	}
190
191	sprintf (tmp, "%d", vp->u.i);
192	vp->type = string;
193	vp->u.s  = tmp;
194}
195
196
197int
198isstring (vp)
199struct val *vp;
200{
201	return (vp->type == string);
202}
203
204
205int
206yylex ()
207{
208	char *p;
209
210	if (*av == NULL)
211		return (0);
212
213	p = *av++;
214
215	if (strlen (p) == 1) {
216		if (strchr ("|&=<>+-*/%:()", *p))
217			return (*p);
218	} else if (strlen (p) == 2 && p[1] == '=') {
219		switch (*p) {
220		case '>': return (GE);
221		case '<': return (LE);
222		case '!': return (NE);
223		}
224	}
225
226	yylval.val = make_str (p);
227	return (TOKEN);
228}
229
230int
231is_zero_or_null (vp)
232struct val *vp;
233{
234	if (vp->type == integer) {
235		return (vp->u.i == 0);
236	} else {
237		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
238	}
239	/* NOTREACHED */
240}
241
242int yyparse ();
243
244void
245main (argc, argv)
246int argc;
247char **argv;
248{
249	setlocale (LC_ALL, "");
250
251	av = argv + 1;
252
253	yyparse ();
254
255	if (result->type == integer)
256		printf ("%d\n", result->u.i);
257	else
258		printf ("%s\n", result->u.s);
259
260	exit (is_zero_or_null (result));
261}
262
263int
264yyerror (s)
265char *s;
266{
267	errx (2, "syntax error");
268}
269
270
271struct val *
272op_or (a, b)
273struct val *a, *b;
274{
275	if (is_zero_or_null (a)) {
276		free_value (a);
277		return (b);
278	} else {
279		free_value (b);
280		return (a);
281	}
282}
283
284struct val *
285op_and (a, b)
286struct val *a, *b;
287{
288	if (is_zero_or_null (a) || is_zero_or_null (b)) {
289		free_value (a);
290		free_value (b);
291		return (make_integer (0));
292	} else {
293		free_value (b);
294		return (a);
295	}
296}
297
298struct val *
299op_eq (a, b)
300struct val *a, *b;
301{
302	struct val *r;
303
304	if (isstring (a) || isstring (b)) {
305		to_string (a);
306		to_string (b);
307		r = make_integer (strcoll (a->u.s, b->u.s) == 0);
308	} else {
309		r = make_integer (a->u.i == b->u.i);
310	}
311
312	free_value (a);
313	free_value (b);
314	return r;
315}
316
317struct val *
318op_gt (a, b)
319struct val *a, *b;
320{
321	struct val *r;
322
323	if (isstring (a) || isstring (b)) {
324		to_string (a);
325		to_string (b);
326		r = make_integer (strcoll (a->u.s, b->u.s) > 0);
327	} else {
328		r= make_integer (a->u.i > b->u.i);
329	}
330
331	free_value (a);
332	free_value (b);
333	return r;
334}
335
336struct val *
337op_lt (a, b)
338struct val *a, *b;
339{
340	struct val *r;
341
342	if (isstring (a) || isstring (b)) {
343		to_string (a);
344		to_string (b);
345		r = make_integer (strcoll (a->u.s, b->u.s) < 0);
346	} else {
347		r = make_integer (a->u.i < b->u.i);
348	}
349
350	free_value (a);
351	free_value (b);
352	return r;
353}
354
355struct val *
356op_ge (a, b)
357struct val *a, *b;
358{
359	struct val *r;
360
361	if (isstring (a) || isstring (b)) {
362		to_string (a);
363		to_string (b);
364		r = make_integer (strcoll (a->u.s, b->u.s) >= 0);
365	} else {
366		r = make_integer (a->u.i >= b->u.i);
367	}
368
369	free_value (a);
370	free_value (b);
371	return r;
372}
373
374struct val *
375op_le (a, b)
376struct val *a, *b;
377{
378	struct val *r;
379
380	if (isstring (a) || isstring (b)) {
381		to_string (a);
382		to_string (b);
383		r = make_integer (strcoll (a->u.s, b->u.s) <= 0);
384	} else {
385		r = make_integer (a->u.i <= b->u.i);
386	}
387
388	free_value (a);
389	free_value (b);
390	return r;
391}
392
393struct val *
394op_ne (a, b)
395struct val *a, *b;
396{
397	struct val *r;
398
399	if (isstring (a) || isstring (b)) {
400		to_string (a);
401		to_string (b);
402		r = make_integer (strcoll (a->u.s, b->u.s) != 0);
403	} else {
404		r = make_integer (a->u.i != b->u.i);
405	}
406
407	free_value (a);
408	free_value (b);
409	return r;
410}
411
412struct val *
413op_plus (a, b)
414struct val *a, *b;
415{
416	struct val *r;
417
418	if (!to_integer (a) || !to_integer (b)) {
419		errx (2, "non-numeric argument");
420	}
421
422	r = make_integer (a->u.i + b->u.i);
423	free_value (a);
424	free_value (b);
425	return r;
426}
427
428struct val *
429op_minus (a, b)
430struct val *a, *b;
431{
432	struct val *r;
433
434	if (!to_integer (a) || !to_integer (b)) {
435		errx (2, "non-numeric argument");
436	}
437
438	r = make_integer (a->u.i - b->u.i);
439	free_value (a);
440	free_value (b);
441	return r;
442}
443
444struct val *
445op_times (a, b)
446struct val *a, *b;
447{
448	struct val *r;
449
450	if (!to_integer (a) || !to_integer (b)) {
451		errx (2, "non-numeric argument");
452	}
453
454	r = make_integer (a->u.i * b->u.i);
455	free_value (a);
456	free_value (b);
457	return (r);
458}
459
460struct val *
461op_div (a, b)
462struct val *a, *b;
463{
464	struct val *r;
465
466	if (!to_integer (a) || !to_integer (b)) {
467		errx (2, "non-numeric argument");
468	}
469
470	if (b->u.i == 0) {
471		errx (2, "division by zero");
472	}
473
474	r = make_integer (a->u.i / b->u.i);
475	free_value (a);
476	free_value (b);
477	return r;
478}
479
480struct val *
481op_rem (a, b)
482struct val *a, *b;
483{
484	struct val *r;
485
486	if (!to_integer (a) || !to_integer (b)) {
487		errx (2, "non-numeric argument");
488	}
489
490	if (b->u.i == 0) {
491		errx (2, "division by zero");
492	}
493
494	r = make_integer (a->u.i % b->u.i);
495	free_value (a);
496	free_value (b);
497	return r;
498}
499
500#include <sys/types.h>
501#include <regex.h>
502
503struct val *
504op_colon (a, b)
505struct val *a, *b;
506{
507	regex_t rp;
508	regmatch_t rm[2];
509	char errbuf[256];
510	int eval;
511	struct val *v;
512
513	/* coerce to both arguments to strings */
514	to_string(a);
515	to_string(b);
516
517	/* compile regular expression */
518	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
519		regerror (eval, &rp, errbuf, sizeof(errbuf));
520		errx (2, "%s", errbuf);
521	}
522
523	/* compare string against pattern */
524	/* remember that patterns are anchored to the beginning of the line */
525	if (regexec(&rp, a->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
526		if (rm[1].rm_so >= 0) {
527			*(a->u.s + rm[1].rm_eo) = '\0';
528			v = make_str (a->u.s + rm[1].rm_so);
529
530		} else {
531			v = make_integer (rm[0].rm_eo - rm[0].rm_so);
532		}
533	} else {
534		if (rp.re_nsub == 0) {
535			v = make_integer (0);
536		} else {
537			v = make_str ("");
538		}
539	}
540
541	/* free arguments and pattern buffer */
542	free_value (a);
543	free_value (b);
544	regfree (&rp);
545
546	return v;
547}
548