expr.y revision 7165 
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 1.8 1994/09/24 02:55:37 davidg 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
111	vp = (struct val *) malloc (sizeof (*vp));
112	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
113		err (2, NULL);
114	}
115
116	vp->type = string;
117	return vp;
118}
119
120
121void
122free_value (vp)
123struct val *vp;
124{
125	if (vp->type == string)
126		free (vp->u.s);
127}
128
129
130int
131to_integer (vp)
132struct val *vp;
133{
134	char *s;
135	int neg;
136	int i;
137
138	if (vp->type == integer)
139		return 1;
140
141	s = vp->u.s;
142	i = 0;
143
144	neg = (*s == '-');
145	if (neg)
146		s++;
147
148	for (;*s; s++) {
149		if (!isdigit (*s))
150			return 0;
151
152		i *= 10;
153		i += *s - '0';
154	}
155
156	free (vp->u.s);
157	if (neg)
158		i *= -1;
159
160	vp->type = integer;
161	vp->u.i  = i;
162	return 1;
163}
164
165void
166to_string (vp)
167struct val *vp;
168{
169	char *tmp;
170
171	if (vp->type == string)
172		return;
173
174	tmp = malloc (25);
175	if (tmp == NULL) {
176		err (2, NULL);
177	}
178
179	sprintf (tmp, "%d", vp->u.i);
180	vp->type = string;
181	vp->u.s  = tmp;
182}
183
184
185int
186isstring (vp)
187struct val *vp;
188{
189	return (vp->type == string);
190}
191
192
193int
194yylex ()
195{
196	char *p;
197
198	if (*av == NULL)
199		return (0);
200
201	p = *av++;
202
203	if (strlen (p) == 1) {
204		if (strchr ("|&=<>+-*/%:()", *p))
205			return (*p);
206	} else if (strlen (p) == 2 && p[1] == '=') {
207		switch (*p) {
208		case '>': return (GE);
209		case '<': return (LE);
210		case '!': return (NE);
211		}
212	}
213
214	yylval.val = make_str (p);
215	return (TOKEN);
216}
217
218int
219is_zero_or_null (vp)
220struct val *vp;
221{
222	if (vp->type == integer) {
223		return (vp->u.i == 0);
224	} else {
225		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
226	}
227	/* NOTREACHED */
228}
229
230int yyparse ();
231
232void
233main (argc, argv)
234int argc;
235char **argv;
236{
237	setlocale (LC_ALL, "");
238
239	av = argv + 1;
240
241	yyparse ();
242
243	if (result->type == integer)
244		printf ("%d\n", result->u.i);
245	else
246		printf ("%s\n", result->u.s);
247
248	exit (is_zero_or_null (result));
249}
250
251int
252yyerror (s)
253char *s;
254{
255	errx (2, "syntax error");
256}
257
258
259struct val *
260op_or (a, b)
261struct val *a, *b;
262{
263	if (is_zero_or_null (a)) {
264		free_value (a);
265		return (b);
266	} else {
267		free_value (b);
268		return (a);
269	}
270}
271
272struct val *
273op_and (a, b)
274struct val *a, *b;
275{
276	if (is_zero_or_null (a) || is_zero_or_null (b)) {
277		free_value (a);
278		free_value (b);
279		return (make_integer (0));
280	} else {
281		free_value (b);
282		return (a);
283	}
284}
285
286struct val *
287op_eq (a, b)
288struct val *a, *b;
289{
290	struct val *r;
291
292	if (isstring (a) || isstring (b)) {
293		to_string (a);
294		to_string (b);
295		r = make_integer (strcoll (a->u.s, b->u.s) == 0);
296	} else {
297		r = make_integer (a->u.i == b->u.i);
298	}
299
300	free_value (a);
301	free_value (b);
302	return r;
303}
304
305struct val *
306op_gt (a, b)
307struct val *a, *b;
308{
309	struct val *r;
310
311	if (isstring (a) || isstring (b)) {
312		to_string (a);
313		to_string (b);
314		r = make_integer (strcoll (a->u.s, b->u.s) > 0);
315	} else {
316		r= make_integer (a->u.i > b->u.i);
317	}
318
319	free_value (a);
320	free_value (b);
321	return r;
322}
323
324struct val *
325op_lt (a, b)
326struct val *a, *b;
327{
328	struct val *r;
329
330	if (isstring (a) || isstring (b)) {
331		to_string (a);
332		to_string (b);
333		r = make_integer (strcoll (a->u.s, b->u.s) < 0);
334	} else {
335		r = make_integer (a->u.i < b->u.i);
336	}
337
338	free_value (a);
339	free_value (b);
340	return r;
341}
342
343struct val *
344op_ge (a, b)
345struct val *a, *b;
346{
347	struct val *r;
348
349	if (isstring (a) || isstring (b)) {
350		to_string (a);
351		to_string (b);
352		r = make_integer (strcoll (a->u.s, b->u.s) >= 0);
353	} else {
354		r = make_integer (a->u.i >= b->u.i);
355	}
356
357	free_value (a);
358	free_value (b);
359	return r;
360}
361
362struct val *
363op_le (a, b)
364struct val *a, *b;
365{
366	struct val *r;
367
368	if (isstring (a) || isstring (b)) {
369		to_string (a);
370		to_string (b);
371		r = make_integer (strcoll (a->u.s, b->u.s) <= 0);
372	} else {
373		r = make_integer (a->u.i <= b->u.i);
374	}
375
376	free_value (a);
377	free_value (b);
378	return r;
379}
380
381struct val *
382op_ne (a, b)
383struct val *a, *b;
384{
385	struct val *r;
386
387	if (isstring (a) || isstring (b)) {
388		to_string (a);
389		to_string (b);
390		r = make_integer (strcoll (a->u.s, b->u.s) != 0);
391	} else {
392		r = make_integer (a->u.i != b->u.i);
393	}
394
395	free_value (a);
396	free_value (b);
397	return r;
398}
399
400struct val *
401op_plus (a, b)
402struct val *a, *b;
403{
404	struct val *r;
405
406	if (!to_integer (a) || !to_integer (b)) {
407		errx (2, "non-numeric argument");
408	}
409
410	r = make_integer (a->u.i + b->u.i);
411	free_value (a);
412	free_value (b);
413	return r;
414}
415
416struct val *
417op_minus (a, b)
418struct val *a, *b;
419{
420	struct val *r;
421
422	if (!to_integer (a) || !to_integer (b)) {
423		errx (2, "non-numeric argument");
424	}
425
426	r = make_integer (a->u.i - b->u.i);
427	free_value (a);
428	free_value (b);
429	return r;
430}
431
432struct val *
433op_times (a, b)
434struct val *a, *b;
435{
436	struct val *r;
437
438	if (!to_integer (a) || !to_integer (b)) {
439		errx (2, "non-numeric argument");
440	}
441
442	r = make_integer (a->u.i * b->u.i);
443	free_value (a);
444	free_value (b);
445	return (r);
446}
447
448struct val *
449op_div (a, b)
450struct val *a, *b;
451{
452	struct val *r;
453
454	if (!to_integer (a) || !to_integer (b)) {
455		errx (2, "non-numeric argument");
456	}
457
458	if (b->u.i == 0) {
459		errx (2, "division by zero");
460	}
461
462	r = make_integer (a->u.i / b->u.i);
463	free_value (a);
464	free_value (b);
465	return r;
466}
467
468struct val *
469op_rem (a, b)
470struct val *a, *b;
471{
472	struct val *r;
473
474	if (!to_integer (a) || !to_integer (b)) {
475		errx (2, "non-numeric argument");
476	}
477
478	if (b->u.i == 0) {
479		errx (2, "division by zero");
480	}
481
482	r = make_integer (a->u.i % b->u.i);
483	free_value (a);
484	free_value (b);
485	return r;
486}
487
488#include <sys/types.h>
489#include <regex.h>
490
491struct val *
492op_colon (a, b)
493struct val *a, *b;
494{
495	regex_t rp;
496	regmatch_t rm[2];
497	char errbuf[256];
498	int eval;
499	struct val *v;
500
501	/* coerce to both arguments to strings */
502	to_string(a);
503	to_string(b);
504
505	/* compile regular expression */
506	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
507		regerror (eval, &rp, errbuf, sizeof(errbuf));
508		errx (2, "%s", errbuf);
509	}
510
511	/* compare string against pattern */
512	/* remember that patterns are anchored to the beginning of the line */
513	if (regexec(&rp, a->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
514		if (rm[1].rm_so >= 0) {
515			*(a->u.s + rm[1].rm_eo) = '\0';
516			v = make_str (a->u.s + rm[1].rm_so);
517
518		} else {
519			v = make_integer (rm[0].rm_eo - rm[0].rm_so);
520		}
521	} else {
522		if (rp.re_nsub == 0) {
523			v = make_integer (0);
524		} else {
525			v = make_str ("");
526		}
527	}
528
529	/* free arguments and pattern buffer */
530	free_value (a);
531	free_value (b);
532	regfree (&rp);
533
534	return v;
535}
536