expr.y revision 539 
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 : /b/source/CVS/src/bin/expr/expr.y,v 1.11 1993/08/17 16:01:23 jtc 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	struct val *vp;
197	char *p;
198
199	if (*av == NULL)
200		return (0);
201
202	p = *av++;
203
204	if (strlen (p) == 1) {
205		if (strchr ("|&=<>+-*/%:()", *p))
206			return (*p);
207	} else if (strlen (p) == 2 && p[1] == '=') {
208		switch (*p) {
209		case '>': return (GE);
210		case '<': return (LE);
211		case '!': return (NE);
212		}
213	}
214
215	yylval.val = make_str (p);
216	return (TOKEN);
217}
218
219int
220is_zero_or_null (vp)
221struct val *vp;
222{
223	if (vp->type == integer) {
224		return (vp->u.i == 0);
225	} else {
226		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
227	}
228	/* NOTREACHED */
229}
230
231void
232main (argc, argv)
233int argc;
234char **argv;
235{
236	setlocale (LC_ALL, "");
237
238	av = argv + 1;
239
240	yyparse ();
241
242	if (result->type == integer)
243		printf ("%d\n", result->u.i);
244	else
245		printf ("%s\n", result->u.s);
246
247	exit (is_zero_or_null (result));
248}
249
250int
251yyerror (s)
252char *s;
253{
254	errx (2, "syntax error");
255}
256
257
258struct val *
259op_or (a, b)
260struct val *a, *b;
261{
262	if (is_zero_or_null (a)) {
263		free_value (a);
264		return (b);
265	} else {
266		free_value (b);
267		return (a);
268	}
269}
270
271struct val *
272op_and (a, b)
273struct val *a, *b;
274{
275	if (is_zero_or_null (a) || is_zero_or_null (b)) {
276		free_value (a);
277		free_value (b);
278		return (make_integer (0));
279	} else {
280		free_value (b);
281		return (a);
282	}
283}
284
285struct val *
286op_eq (a, b)
287struct val *a, *b;
288{
289	struct val *r;
290
291	if (isstring (a) || isstring (b)) {
292		to_string (a);
293		to_string (b);
294		r = make_integer (strcoll (a->u.s, b->u.s) == 0);
295	} else {
296		r = make_integer (a->u.i == b->u.i);
297	}
298
299	free_value (a);
300	free_value (b);
301	return r;
302}
303
304struct val *
305op_gt (a, b)
306struct val *a, *b;
307{
308	struct val *r;
309
310	if (isstring (a) || isstring (b)) {
311		to_string (a);
312		to_string (b);
313		r = make_integer (strcoll (a->u.s, b->u.s) > 0);
314	} else {
315		r= make_integer (a->u.i > b->u.i);
316	}
317
318	free_value (a);
319	free_value (b);
320	return r;
321}
322
323struct val *
324op_lt (a, b)
325struct val *a, *b;
326{
327	struct val *r;
328
329	if (isstring (a) || isstring (b)) {
330		to_string (a);
331		to_string (b);
332		r = make_integer (strcoll (a->u.s, b->u.s) < 0);
333	} else {
334		r = make_integer (a->u.i < b->u.i);
335	}
336
337	free_value (a);
338	free_value (b);
339	return r;
340}
341
342struct val *
343op_ge (a, b)
344struct val *a, *b;
345{
346	struct val *r;
347
348	if (isstring (a) || isstring (b)) {
349		to_string (a);
350		to_string (b);
351		r = make_integer (strcoll (a->u.s, b->u.s) >= 0);
352	} else {
353		r = make_integer (a->u.i >= b->u.i);
354	}
355
356	free_value (a);
357	free_value (b);
358	return r;
359}
360
361struct val *
362op_le (a, b)
363struct val *a, *b;
364{
365	struct val *r;
366
367	if (isstring (a) || isstring (b)) {
368		to_string (a);
369		to_string (b);
370		r = make_integer (strcoll (a->u.s, b->u.s) <= 0);
371	} else {
372		r = make_integer (a->u.i <= b->u.i);
373	}
374
375	free_value (a);
376	free_value (b);
377	return r;
378}
379
380struct val *
381op_ne (a, b)
382struct val *a, *b;
383{
384	struct val *r;
385
386	if (isstring (a) || isstring (b)) {
387		to_string (a);
388		to_string (b);
389		r = make_integer (strcoll (a->u.s, b->u.s) != 0);
390	} else {
391		r = make_integer (a->u.i != b->u.i);
392	}
393
394	free_value (a);
395	free_value (b);
396	return r;
397}
398
399struct val *
400op_plus (a, b)
401struct val *a, *b;
402{
403	struct val *r;
404
405	if (!to_integer (a) || !to_integer (b)) {
406		errx (2, "non-numeric argument");
407	}
408
409	r = make_integer (a->u.i + b->u.i);
410	free_value (a);
411	free_value (b);
412	return r;
413}
414
415struct val *
416op_minus (a, b)
417struct val *a, *b;
418{
419	struct val *r;
420
421	if (!to_integer (a) || !to_integer (b)) {
422		errx (2, "non-numeric argument");
423	}
424
425	r = make_integer (a->u.i - b->u.i);
426	free_value (a);
427	free_value (b);
428	return r;
429}
430
431struct val *
432op_times (a, b)
433struct val *a, *b;
434{
435	struct val *r;
436
437	if (!to_integer (a) || !to_integer (b)) {
438		errx (2, "non-numeric argument");
439	}
440
441	r = make_integer (a->u.i * b->u.i);
442	free_value (a);
443	free_value (b);
444	return (r);
445}
446
447struct val *
448op_div (a, b)
449struct val *a, *b;
450{
451	struct val *r;
452
453	if (!to_integer (a) || !to_integer (b)) {
454		errx (2, "non-numeric argument");
455	}
456
457	if (b->u.i == 0) {
458		errx (2, "division by zero");
459	}
460
461	r = make_integer (a->u.i / b->u.i);
462	free_value (a);
463	free_value (b);
464	return r;
465}
466
467struct val *
468op_rem (a, b)
469struct val *a, *b;
470{
471	struct val *r;
472
473	if (!to_integer (a) || !to_integer (b)) {
474		errx (2, "non-numeric argument");
475	}
476
477	if (b->u.i == 0) {
478		errx (2, "division by zero");
479	}
480
481	r = make_integer (a->u.i % b->u.i);
482	free_value (a);
483	free_value (b);
484	return r;
485}
486
487#include <regex.h>
488
489struct val *
490op_colon (a, b)
491struct val *a, *b;
492{
493	regex_t rp;
494	regmatch_t rm[2];
495	char errbuf[256];
496	int eval;
497	struct val *v;
498
499	/* coerce to both arguments to strings */
500	to_string(a);
501	to_string(b);
502
503	/* compile regular expression */
504	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
505		regerror (eval, &rp, errbuf, sizeof(errbuf));
506		errx (2, "%s", errbuf);
507	}
508
509	/* compare string against pattern */
510	/* remember that patterns are anchored to the beginning of the line */
511	if (regexec(&rp, a->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
512		if (rm[1].rm_so >= 0) {
513			*(a->u.s + rm[1].rm_eo) = '\0';
514			v = make_str (a->u.s + rm[1].rm_so);
515
516		} else {
517			v = make_integer (rm[0].rm_eo - rm[0].rm_so);
518		}
519	} else {
520		if (rp.re_nsub == 0) {
521			v = make_integer (0);
522		} else {
523			v = make_str ("");
524		}
525	}
526
527	/* free arguments and pattern buffer */
528	free_value (a);
529	free_value (b);
530	regfree (&rp);
531
532	return v;
533}
534