expr.y revision 62926 
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 * $FreeBSD: head/bin/expr/expr.y 62926 2000-07-10 21:30:55Z se $
8 */
9
10#include <sys/types.h>
11#include <stdio.h>
12#include <stdlib.h>
13#include <string.h>
14#include <locale.h>
15#include <ctype.h>
16#include <err.h>
17#include <regex.h>
18
19enum valtype {
20	integer, numeric_string, string
21} ;
22
23struct val {
24	enum valtype type;
25	union {
26		char *s;
27		quad_t i;
28	} u;
29} ;
30
31struct val *result;
32struct val *op_or ();
33struct val *op_and ();
34struct val *op_eq ();
35struct val *op_gt ();
36struct val *op_lt ();
37struct val *op_ge ();
38struct val *op_le ();
39struct val *op_ne ();
40struct val *op_plus ();
41struct val *op_minus ();
42struct val *op_times ();
43struct val *op_div ();
44struct val *op_rem ();
45struct val *op_colon ();
46
47char **av;
48%}
49
50%union
51{
52	struct val *val;
53}
54
55%left <val> '|'
56%left <val> '&'
57%left <val> '=' '>' '<' GE LE NE
58%left <val> '+' '-'
59%left <val> '*' '/' '%'
60%left <val> ':'
61
62%token <val> TOKEN
63%type <val> start expr
64
65%%
66
67start: expr { result = $$; }
68
69expr:	TOKEN
70	| '(' expr ')' { $$ = $2; }
71	| expr '|' expr { $$ = op_or ($1, $3); }
72	| expr '&' expr { $$ = op_and ($1, $3); }
73	| expr '=' expr { $$ = op_eq ($1, $3); }
74	| expr '>' expr { $$ = op_gt ($1, $3); }
75	| expr '<' expr { $$ = op_lt ($1, $3); }
76	| expr GE expr  { $$ = op_ge ($1, $3); }
77	| expr LE expr  { $$ = op_le ($1, $3); }
78	| expr NE expr  { $$ = op_ne ($1, $3); }
79	| expr '+' expr { $$ = op_plus ($1, $3); }
80	| expr '-' expr { $$ = op_minus ($1, $3); }
81	| expr '*' expr { $$ = op_times ($1, $3); }
82	| expr '/' expr { $$ = op_div ($1, $3); }
83	| expr '%' expr { $$ = op_rem ($1, $3); }
84	| expr ':' expr { $$ = op_colon ($1, $3); }
85	;
86
87
88%%
89
90struct val *
91make_integer (i)
92quad_t i;
93{
94	struct val *vp;
95
96	vp = (struct val *) malloc (sizeof (*vp));
97	if (vp == NULL) {
98		errx (2, "malloc() failed");
99	}
100
101	vp->type = integer;
102	vp->u.i  = i;
103	return vp;
104}
105
106struct val *
107make_str (s)
108char *s;
109{
110	struct val *vp;
111	int i, isint;
112
113	vp = (struct val *) malloc (sizeof (*vp));
114	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
115		errx (2, "malloc() failed");
116	}
117
118	for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
119	    isint && i < strlen(s);
120	    i++)
121	{
122		if(!isdigit(s[i]))
123			 isint = 0;
124	}
125
126	if (isint)
127		vp->type = numeric_string;
128	else
129		vp->type = string;
130
131	return vp;
132}
133
134
135void
136free_value (vp)
137struct val *vp;
138{
139	if (vp->type == string || vp->type == numeric_string)
140		free (vp->u.s);
141}
142
143
144quad_t
145to_integer (vp)
146struct val *vp;
147{
148	quad_t i;
149
150	if (vp->type == integer)
151		return 1;
152
153	if (vp->type == string)
154		return 0;
155
156	/* vp->type == numeric_string, make it numeric */
157	i  = strtoq(vp->u.s, (char**)NULL, 10);
158	free (vp->u.s);
159	vp->u.i = i;
160	vp->type = integer;
161	return 1;
162}
163
164void
165to_string (vp)
166struct val *vp;
167{
168	char *tmp;
169
170	if (vp->type == string || vp->type == numeric_string)
171		return;
172
173	tmp = malloc (25);
174	if (tmp == NULL) {
175		errx (2, "malloc() failed");
176	}
177
178	sprintf (tmp, "%qd", vp->u.i);
179	vp->type = string;
180	vp->u.s  = tmp;
181}
182
183
184int
185isstring (vp)
186struct val *vp;
187{
188	/* only TRUE if this string is not a valid integer */
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
232int
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 ("%qd\n", result->u.i);
245	else
246		printf ("%s\n", result->u.s);
247
248	return (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 ((quad_t)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 ((quad_t)(strcoll (a->u.s, b->u.s) == 0));
296	} else {
297		(void)to_integer(a);
298		(void)to_integer(b);
299		r = make_integer ((quad_t)(a->u.i == b->u.i));
300	}
301
302	free_value (a);
303	free_value (b);
304	return r;
305}
306
307struct val *
308op_gt (a, b)
309struct val *a, *b;
310{
311	struct val *r;
312
313	if (isstring (a) || isstring (b)) {
314		to_string (a);
315		to_string (b);
316		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) > 0));
317	} else {
318		(void)to_integer(a);
319		(void)to_integer(b);
320		r = make_integer ((quad_t)(a->u.i > b->u.i));
321	}
322
323	free_value (a);
324	free_value (b);
325	return r;
326}
327
328struct val *
329op_lt (a, b)
330struct val *a, *b;
331{
332	struct val *r;
333
334	if (isstring (a) || isstring (b)) {
335		to_string (a);
336		to_string (b);
337		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) < 0));
338	} else {
339		(void)to_integer(a);
340		(void)to_integer(b);
341		r = make_integer ((quad_t)(a->u.i < b->u.i));
342	}
343
344	free_value (a);
345	free_value (b);
346	return r;
347}
348
349struct val *
350op_ge (a, b)
351struct val *a, *b;
352{
353	struct val *r;
354
355	if (isstring (a) || isstring (b)) {
356		to_string (a);
357		to_string (b);
358		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) >= 0));
359	} else {
360		(void)to_integer(a);
361		(void)to_integer(b);
362		r = make_integer ((quad_t)(a->u.i >= b->u.i));
363	}
364
365	free_value (a);
366	free_value (b);
367	return r;
368}
369
370struct val *
371op_le (a, b)
372struct val *a, *b;
373{
374	struct val *r;
375
376	if (isstring (a) || isstring (b)) {
377		to_string (a);
378		to_string (b);
379		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) <= 0));
380	} else {
381		(void)to_integer(a);
382		(void)to_integer(b);
383		r = make_integer ((quad_t)(a->u.i <= b->u.i));
384	}
385
386	free_value (a);
387	free_value (b);
388	return r;
389}
390
391struct val *
392op_ne (a, b)
393struct val *a, *b;
394{
395	struct val *r;
396
397	if (isstring (a) || isstring (b)) {
398		to_string (a);
399		to_string (b);
400		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) != 0));
401	} else {
402		(void)to_integer(a);
403		(void)to_integer(b);
404		r = make_integer ((quad_t)(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 (/*(quad_t)*/(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 (/*(quad_t)*/(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 (/*(quad_t)*/(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 (/*(quad_t)*/(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 (/*(quad_t)*/(a->u.i % b->u.i));
495	free_value (a);
496	free_value (b);
497	return r;
498}
499
500struct val *
501op_colon (a, b)
502struct val *a, *b;
503{
504	regex_t rp;
505	regmatch_t rm[2];
506	char errbuf[256];
507	int eval;
508	struct val *v;
509
510	/* coerce to both arguments to strings */
511	to_string(a);
512	to_string(b);
513
514	/* compile regular expression */
515	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
516		regerror (eval, &rp, errbuf, sizeof(errbuf));
517		errx (2, "%s", errbuf);
518	}
519
520	/* compare string against pattern */
521	/* remember that patterns are anchored to the beginning of the line */
522	if (regexec(&rp, a->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
523		if (rm[1].rm_so >= 0) {
524			*(a->u.s + rm[1].rm_eo) = '\0';
525			v = make_str (a->u.s + rm[1].rm_so);
526
527		} else {
528			v = make_integer ((quad_t)(rm[0].rm_eo - rm[0].rm_so));
529		}
530	} else {
531		if (rp.re_nsub == 0) {
532			v = make_integer ((quad_t)0);
533		} else {
534			v = make_str ("");
535		}
536	}
537
538	/* free arguments and pattern buffer */
539	free_value (a);
540	free_value (b);
541	regfree (&rp);
542
543	return v;
544}
545