busybox/coreutils/expr.c

/* vi: set sw=4 ts=4: */
/*
 * Mini expr implementation for busybox
 *
 * based on GNU expr Mike Parker.
 * Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc.
 *
 * Busybox modifications
 * Copyright (c) 2000  Edward Betts <edward@debian.org>.
 * Copyright (C) 2003-2005  Vladimir Oleynik <dzo@simtreas.ru>
 *  - reduced 464 bytes.
 *  - 64 math support
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* This program evaluates expressions.  Each token (operator, operand,
 * parenthesis) of the expression must be a separate argument.  The
 * parser used is a reasonably general one, though any incarnation of
 * it is language-specific.  It is especially nice for expressions.
 *
 * No parse tree is needed; a new node is evaluated immediately.
 * One function can handle multiple operators all of equal precedence,
 * provided they all associate ((x op x) op x). */

/* no getopt needed */

#include "busybox.h"
#include "xregex.h"

/* The kinds of value we can have.  */
enum valtype {
	integer,
	string
};
typedef enum valtype TYPE;

#if ENABLE_EXPR_MATH_SUPPORT_64
typedef int64_t arith_t;

#define PF_REZ      "ll"
#define PF_REZ_TYPE (long long)
#define STRTOL(s, e, b) strtoll(s, e, b)
#else
typedef long arith_t;

#define PF_REZ      "l"
#define PF_REZ_TYPE (long)
#define STRTOL(s, e, b) strtol(s, e, b)
#endif

/* TODO: use bb_strtol[l]? It's easier to check for errors... */

/* A value is.... */
struct valinfo {
	TYPE type;			/* Which kind. */
	union {				/* The value itself. */
		arith_t i;
		char *s;
	} u;
};
typedef struct valinfo VALUE;

/* The arguments given to the program, minus the program name.  */
static char **args;

static VALUE *docolon(VALUE * sv, VALUE * pv);
static VALUE *eval(void);
static VALUE *int_value(arith_t i);
static VALUE *str_value(char *s);
static int nextarg(char *str);
static int null(VALUE * v);
static int toarith(VALUE * v);
static void freev(VALUE * v);
static void tostring(VALUE * v);

int expr_main(int argc, char **argv)
{
	VALUE *v;

	if (argc == 1) {
		bb_error_msg_and_die("too few arguments");
	}

	args = argv + 1;

	v = eval();
	if (*args)
		bb_error_msg_and_die("syntax error");

	if (v->type == integer)
		printf("%" PF_REZ "d\n", PF_REZ_TYPE v->u.i);
	else
		puts(v->u.s);

	fflush_stdout_and_exit(null(v));
}

/* Return a VALUE for I.  */

static VALUE *int_value(arith_t i)
{
	VALUE *v;

	v = xmalloc(sizeof(VALUE));
	v->type = integer;
	v->u.i = i;
	return v;
}

/* Return a VALUE for S.  */

static VALUE *str_value(char *s)
{
	VALUE *v;

	v = xmalloc(sizeof(VALUE));
	v->type = string;
	v->u.s = xstrdup(s);
	return v;
}

/* Free VALUE V, including structure components.  */

static void freev(VALUE * v)
{
	if (v->type == string)
		free(v->u.s);
	free(v);
}

/* Return nonzero if V is a null-string or zero-number.  */

static int null(VALUE * v)
{
	if (v->type == integer)
		return v->u.i == 0;
	else				/* string: */
		return v->u.s[0] == '\0' || LONE_CHAR(v->u.s, '0');
}

/* Coerce V to a string value (can't fail).  */

static void tostring(VALUE * v)
{
	if (v->type == integer) {
		v->u.s = xasprintf("%" PF_REZ "d", PF_REZ_TYPE v->u.i);
		v->type = string;
	}
}

/* Coerce V to an integer value.  Return 1 on success, 0 on failure.  */

static int toarith(VALUE * v)
{
	if (v->type == string) {
		arith_t i;
		char *e;

		/* Don't interpret the empty string as an integer.  */
		/* Currently does not worry about overflow or int/long differences. */
		i = STRTOL(v->u.s, &e, 10);
		if ((v->u.s == e) || *e)
			return 0;
		free(v->u.s);
		v->u.i = i;
		v->type = integer;
	}
	return 1;
}

/* Return nonzero if the next token matches STR exactly.
   STR must not be NULL.  */

static int nextarg(char *str)
{
	if (*args == NULL)
		return 0;
	return strcmp(*args, str) == 0;
}

/* The comparison operator handling functions.  */

static int cmp_common(VALUE * l, VALUE * r, int op)
{
	int cmpval;

	if (l->type == string || r->type == string) {
		tostring(l);
		tostring(r);
		cmpval = strcmp(l->u.s, r->u.s);
	} else
		cmpval = l->u.i - r->u.i;
	if (op == '<')
		return cmpval < 0;
	else if (op == ('L' + 'E'))
		return cmpval <= 0;
	else if (op == '=')
		return cmpval == 0;
	else if (op == '!')
		return cmpval != 0;
	else if (op == '>')
		return cmpval > 0;
	else				/* >= */
		return cmpval >= 0;
}

/* The arithmetic operator handling functions.  */

static arith_t arithmetic_common(VALUE * l, VALUE * r, int op)
{
	arith_t li, ri;

	if (!toarith(l) || !toarith(r))
		bb_error_msg_and_die("non-numeric argument");
	li = l->u.i;
	ri = r->u.i;
	if ((op == '/' || op == '%') && ri == 0)
		bb_error_msg_and_die("division by zero");
	if (op == '+')
		return li + ri;
	else if (op == '-')
		return li - ri;
	else if (op == '*')
		return li * ri;
	else if (op == '/')
		return li / ri;
	else
		return li % ri;
}

/* Do the : operator.
   SV is the VALUE for the lhs (the string),
   PV is the VALUE for the rhs (the pattern).  */

static VALUE *docolon(VALUE * sv, VALUE * pv)
{
	VALUE *v;
	regex_t re_buffer;
	const int NMATCH = 2;
	regmatch_t re_regs[NMATCH];

	tostring(sv);
	tostring(pv);

	if (pv->u.s[0] == '^') {
		fprintf(stderr, "\
warning: unportable BRE: `%s': using `^' as the first character\n\
of a basic regular expression is not portable; it is being ignored", pv->u.s);
	}

	memset(&re_buffer, 0, sizeof(re_buffer));
	memset(re_regs, 0, sizeof(*re_regs));
	if (regcomp(&re_buffer, pv->u.s, 0) != 0)
		bb_error_msg_and_die("invalid regular expression");

	/* expr uses an anchored pattern match, so check that there was a
	 * match and that the match starts at offset 0. */
	if (regexec(&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH &&
		re_regs[0].rm_so == 0) {
		/* Were \(...\) used? */
		if (re_buffer.re_nsub > 0) {
			sv->u.s[re_regs[1].rm_eo] = '\0';
			v = str_value(sv->u.s + re_regs[1].rm_so);
		} else
			v = int_value(re_regs[0].rm_eo);
	} else {
		/* Match failed -- return the right kind of null.  */
		if (re_buffer.re_nsub > 0)
			v = str_value("");
		else
			v = int_value(0);
	}
	return v;
}

/* Handle bare operands and ( expr ) syntax.  */

static VALUE *eval7(void)
{
	VALUE *v;

	if (!*args)
		bb_error_msg_and_die("syntax error");

	if (nextarg("(")) {
		args++;
		v = eval();
		if (!nextarg(")"))
			bb_error_msg_and_die("syntax error");
		args++;
		return v;
	}

	if (nextarg(")"))
		bb_error_msg_and_die("syntax error");

	return str_value(*args++);
}

/* Handle match, substr, index, length, and quote keywords.  */

static VALUE *eval6(void)
{
	VALUE *l, *r, *v, *i1, *i2;

	if (nextarg("quote")) {
		args++;
		if (!*args)
			bb_error_msg_and_die("syntax error");
		return str_value(*args++);
	} else if (nextarg("length")) {
		args++;
		r = eval6();
		tostring(r);
		v = int_value(strlen(r->u.s));
		freev(r);
		return v;
	} else if (nextarg("match")) {
		args++;
		l = eval6();
		r = eval6();
		v = docolon(l, r);
		freev(l);
		freev(r);
		return v;
	} else if (nextarg("index")) {
		args++;
		l = eval6();
		r = eval6();
		tostring(l);
		tostring(r);
		v = int_value(strcspn(l->u.s, r->u.s) + 1);
		if (v->u.i == (arith_t) strlen(l->u.s) + 1)
			v->u.i = 0;
		freev(l);
		freev(r);
		return v;
	} else if (nextarg("substr")) {
		args++;
		l = eval6();
		i1 = eval6();
		i2 = eval6();
		tostring(l);
		if (!toarith(i1) || !toarith(i2)
			|| i1->u.i > (arith_t) strlen(l->u.s)
			|| i1->u.i <= 0 || i2->u.i <= 0)
			v = str_value("");
		else {
			v = xmalloc(sizeof(VALUE));
			v->type = string;
			v->u.s = xstrndup(l->u.s + i1->u.i - 1, i2->u.i);
		}
		freev(l);
		freev(i1);
		freev(i2);
		return v;
	} else
		return eval7();
}

/* Handle : operator (pattern matching).
   Calls docolon to do the real work.  */

static VALUE *eval5(void)
{
	VALUE *l, *r, *v;

	l = eval6();
	while (nextarg(":")) {
		args++;
		r = eval6();
		v = docolon(l, r);
		freev(l);
		freev(r);
		l = v;
	}
	return l;
}

/* Handle *, /, % operators.  */

static VALUE *eval4(void)
{
	VALUE *l, *r;
	int op;
	arith_t val;

	l = eval5();
	while (1) {
		if (nextarg("*"))
			op = '*';
		else if (nextarg("/"))
			op = '/';
		else if (nextarg("%"))
			op = '%';
		else
			return l;
		args++;
		r = eval5();
		val = arithmetic_common(l, r, op);
		freev(l);
		freev(r);
		l = int_value(val);
	}
}

/* Handle +, - operators.  */

static VALUE *eval3(void)
{
	VALUE *l, *r;
	int op;
	arith_t val;

	l = eval4();
	while (1) {
		if (nextarg("+"))
			op = '+';
		else if (nextarg("-"))
			op = '-';
		else
			return l;
		args++;
		r = eval4();
		val = arithmetic_common(l, r, op);
		freev(l);
		freev(r);
		l = int_value(val);
	}
}

/* Handle comparisons.  */

static VALUE *eval2(void)
{
	VALUE *l, *r;
	int op;
	arith_t val;

	l = eval3();
	while (1) {
		if (nextarg("<"))
			op = '<';
		else if (nextarg("<="))
			op = 'L' + 'E';
		else if (nextarg("=") || nextarg("=="))
			op = '=';
		else if (nextarg("!="))
			op = '!';
		else if (nextarg(">="))
			op = 'G' + 'E';
		else if (nextarg(">"))
			op = '>';
		else
			return l;
		args++;
		r = eval3();
		toarith(l);
		toarith(r);
		val = cmp_common(l, r, op);
		freev(l);
		freev(r);
		l = int_value(val);
	}
}

/* Handle &.  */

static VALUE *eval1(void)
{
	VALUE *l, *r;

	l = eval2();
	while (nextarg("&")) {
		args++;
		r = eval2();
		if (null(l) || null(r)) {
			freev(l);
			freev(r);
			l = int_value(0);
		} else
			freev(r);
	}
	return l;
}

/* Handle |.  */

static VALUE *eval(void)
{
	VALUE *l, *r;

	l = eval1();
	while (nextarg("|")) {
		args++;
		r = eval1();
		if (null(l)) {
			freev(l);
			l = r;
		} else
			freev(r);
	}
	return l;
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Mini expr implementation for busybox
4	*
5	* based on GNU expr Mike Parker.
6	* Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc.
7	*
8	* Busybox modifications
9	* Copyright (c) 2000 Edward Betts <edward@debian.org>.
10	* Copyright (C) 2003-2005 Vladimir Oleynik <dzo@simtreas.ru>
11	* - reduced 464 bytes.
12	* - 64 math support
13	*
14	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
15	*/
16
17	/* This program evaluates expressions. Each token (operator, operand,
18	* parenthesis) of the expression must be a separate argument. The
19	* parser used is a reasonably general one, though any incarnation of
20	* it is language-specific. It is especially nice for expressions.
21	*
22	* No parse tree is needed; a new node is evaluated immediately.
23	* One function can handle multiple operators all of equal precedence,
24	* provided they all associate ((x op x) op x). */
25
26	/* no getopt needed */
27
28	#include "busybox.h"
29	#include "xregex.h"
30
31	/* The kinds of value we can have. */
32	enum valtype {
33	integer,
34	string
35	};
36	typedef enum valtype TYPE;
37
38	#if ENABLE_EXPR_MATH_SUPPORT_64
39	typedef int64_t arith_t;
40
41	#define PF_REZ "ll"
42	#define PF_REZ_TYPE (long long)
43	#define STRTOL(s, e, b) strtoll(s, e, b)
44	#else
45	typedef long arith_t;
46
47	#define PF_REZ "l"
48	#define PF_REZ_TYPE (long)
49	#define STRTOL(s, e, b) strtol(s, e, b)
50	#endif
51
52	/* TODO: use bb_strtol[l]? It's easier to check for errors... */
53
54	/* A value is.... */
55	struct valinfo {
56	TYPE type; /* Which kind. */
57	union { /* The value itself. */
58	arith_t i;
59	char *s;
60	} u;
61	};
62	typedef struct valinfo VALUE;
63
64	/* The arguments given to the program, minus the program name. */
65	static char **args;
66
67	static VALUE docolon(VALUE sv, VALUE * pv);
68	static VALUE *eval(void);
69	static VALUE *int_value(arith_t i);
70	static VALUE str_value(char s);
71	static int nextarg(char *str);
72	static int null(VALUE * v);
73	static int toarith(VALUE * v);
74	static void freev(VALUE * v);
75	static void tostring(VALUE * v);
76
77	int expr_main(int argc, char **argv)
78	{
79	VALUE *v;
80
81	if (argc == 1) {
82	bb_error_msg_and_die("too few arguments");
83	}
84
85	args = argv + 1;
86
87	v = eval();
88	if (*args)
89	bb_error_msg_and_die("syntax error");
90
91	if (v->type == integer)
92	printf("%" PF_REZ "d\n", PF_REZ_TYPE v->u.i);
93	else
94	puts(v->u.s);
95
96	fflush_stdout_and_exit(null(v));
97	}
98
99	/* Return a VALUE for I. */
100
101	static VALUE *int_value(arith_t i)
102	{
103	VALUE *v;
104
105	v = xmalloc(sizeof(VALUE));
106	v->type = integer;
107	v->u.i = i;
108	return v;
109	}
110
111	/* Return a VALUE for S. */
112
113	static VALUE str_value(char s)
114	{
115	VALUE *v;
116
117	v = xmalloc(sizeof(VALUE));
118	v->type = string;
119	v->u.s = xstrdup(s);
120	return v;
121	}
122
123	/* Free VALUE V, including structure components. */
124
125	static void freev(VALUE * v)
126	{
127	if (v->type == string)
128	free(v->u.s);
129	free(v);
130	}
131
132	/* Return nonzero if V is a null-string or zero-number. */
133
134	static int null(VALUE * v)
135	{
136	if (v->type == integer)
137	return v->u.i == 0;
138	else /* string: */
139	return v->u.s[0] == '\0' \|\| LONE_CHAR(v->u.s, '0');
140	}
141
142	/* Coerce V to a string value (can't fail). */
143
144	static void tostring(VALUE * v)
145	{
146	if (v->type == integer) {
147	v->u.s = xasprintf("%" PF_REZ "d", PF_REZ_TYPE v->u.i);
148	v->type = string;
149	}
150	}
151
152	/* Coerce V to an integer value. Return 1 on success, 0 on failure. */
153
154	static int toarith(VALUE * v)
155	{
156	if (v->type == string) {
157	arith_t i;
158	char *e;
159
160	/* Don't interpret the empty string as an integer. */
161	/* Currently does not worry about overflow or int/long differences. */
162	i = STRTOL(v->u.s, &e, 10);
163	if ((v->u.s == e) \|\| *e)
164	return 0;
165	free(v->u.s);
166	v->u.i = i;
167	v->type = integer;
168	}
169	return 1;
170	}
171
172	/* Return nonzero if the next token matches STR exactly.
173	STR must not be NULL. */
174
175	static int nextarg(char *str)
176	{
177	if (*args == NULL)
178	return 0;
179	return strcmp(*args, str) == 0;
180	}
181
182	/* The comparison operator handling functions. */
183
184	static int cmp_common(VALUE * l, VALUE * r, int op)
185	{
186	int cmpval;
187
188	if (l->type == string \|\| r->type == string) {
189	tostring(l);
190	tostring(r);
191	cmpval = strcmp(l->u.s, r->u.s);
192	} else
193	cmpval = l->u.i - r->u.i;
194	if (op == '<')
195	return cmpval < 0;
196	else if (op == ('L' + 'E'))
197	return cmpval <= 0;
198	else if (op == '=')
199	return cmpval == 0;
200	else if (op == '!')
201	return cmpval != 0;
202	else if (op == '>')
203	return cmpval > 0;
204	else /* >= */
205	return cmpval >= 0;
206	}
207
208	/* The arithmetic operator handling functions. */
209
210	static arith_t arithmetic_common(VALUE * l, VALUE * r, int op)
211	{
212	arith_t li, ri;
213
214	if (!toarith(l) \|\| !toarith(r))
215	bb_error_msg_and_die("non-numeric argument");
216	li = l->u.i;
217	ri = r->u.i;
218	if ((op == '/' \|\| op == '%') && ri == 0)
219	bb_error_msg_and_die("division by zero");
220	if (op == '+')
221	return li + ri;
222	else if (op == '-')
223	return li - ri;
224	else if (op == '*')
225	return li * ri;
226	else if (op == '/')
227	return li / ri;
228	else
229	return li % ri;
230	}
231
232	/* Do the : operator.
233	SV is the VALUE for the lhs (the string),
234	PV is the VALUE for the rhs (the pattern). */
235
236	static VALUE docolon(VALUE sv, VALUE * pv)
237	{
238	VALUE *v;
239	regex_t re_buffer;
240	const int NMATCH = 2;
241	regmatch_t re_regs[NMATCH];
242
243	tostring(sv);
244	tostring(pv);
245
246	if (pv->u.s[0] == '^') {
247	fprintf(stderr, "\
248	warning: unportable BRE: `%s': using `^' as the first character\n\
249	of a basic regular expression is not portable; it is being ignored", pv->u.s);
250	}
251
252	memset(&re_buffer, 0, sizeof(re_buffer));
253	memset(re_regs, 0, sizeof(*re_regs));
254	if (regcomp(&re_buffer, pv->u.s, 0) != 0)
255	bb_error_msg_and_die("invalid regular expression");
256
257	/* expr uses an anchored pattern match, so check that there was a
258	* match and that the match starts at offset 0. */
259	if (regexec(&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH &&
260	re_regs[0].rm_so == 0) {
261	/* Were \(...\) used? */
262	if (re_buffer.re_nsub > 0) {
263	sv->u.s[re_regs[1].rm_eo] = '\0';
264	v = str_value(sv->u.s + re_regs[1].rm_so);
265	} else
266	v = int_value(re_regs[0].rm_eo);
267	} else {
268	/* Match failed -- return the right kind of null. */
269	if (re_buffer.re_nsub > 0)
270	v = str_value("");
271	else
272	v = int_value(0);
273	}
274	return v;
275	}
276
277	/* Handle bare operands and ( expr ) syntax. */
278
279	static VALUE *eval7(void)
280	{
281	VALUE *v;
282
283	if (!*args)
284	bb_error_msg_and_die("syntax error");
285
286	if (nextarg("(")) {
287	args++;
288	v = eval();
289	if (!nextarg(")"))
290	bb_error_msg_and_die("syntax error");
291	args++;
292	return v;
293	}
294
295	if (nextarg(")"))
296	bb_error_msg_and_die("syntax error");
297
298	return str_value(*args++);
299	}
300
301	/* Handle match, substr, index, length, and quote keywords. */
302
303	static VALUE *eval6(void)
304	{
305	VALUE l, r, v, i1, *i2;
306
307	if (nextarg("quote")) {
308	args++;
309	if (!*args)
310	bb_error_msg_and_die("syntax error");
311	return str_value(*args++);
312	} else if (nextarg("length")) {
313	args++;
314	r = eval6();
315	tostring(r);
316	v = int_value(strlen(r->u.s));
317	freev(r);
318	return v;
319	} else if (nextarg("match")) {
320	args++;
321	l = eval6();
322	r = eval6();
323	v = docolon(l, r);
324	freev(l);
325	freev(r);
326	return v;
327	} else if (nextarg("index")) {
328	args++;
329	l = eval6();
330	r = eval6();
331	tostring(l);
332	tostring(r);
333	v = int_value(strcspn(l->u.s, r->u.s) + 1);
334	if (v->u.i == (arith_t) strlen(l->u.s) + 1)
335	v->u.i = 0;
336	freev(l);
337	freev(r);
338	return v;
339	} else if (nextarg("substr")) {
340	args++;
341	l = eval6();
342	i1 = eval6();
343	i2 = eval6();
344	tostring(l);
345	if (!toarith(i1) \|\| !toarith(i2)
346	\|\| i1->u.i > (arith_t) strlen(l->u.s)
347	\|\| i1->u.i <= 0 \|\| i2->u.i <= 0)
348	v = str_value("");
349	else {
350	v = xmalloc(sizeof(VALUE));
351	v->type = string;
352	v->u.s = xstrndup(l->u.s + i1->u.i - 1, i2->u.i);
353	}
354	freev(l);
355	freev(i1);
356	freev(i2);
357	return v;
358	} else
359	return eval7();
360	}
361
362	/* Handle : operator (pattern matching).
363	Calls docolon to do the real work. */
364
365	static VALUE *eval5(void)
366	{
367	VALUE l, r, *v;
368
369	l = eval6();
370	while (nextarg(":")) {
371	args++;
372	r = eval6();
373	v = docolon(l, r);
374	freev(l);
375	freev(r);
376	l = v;
377	}
378	return l;
379	}
380
381	/* Handle , /, % operators. /
382
383	static VALUE *eval4(void)
384	{
385	VALUE l, r;
386	int op;
387	arith_t val;
388
389	l = eval5();
390	while (1) {
391	if (nextarg("*"))
392	op = '*';
393	else if (nextarg("/"))
394	op = '/';
395	else if (nextarg("%"))
396	op = '%';
397	else
398	return l;
399	args++;
400	r = eval5();
401	val = arithmetic_common(l, r, op);
402	freev(l);
403	freev(r);
404	l = int_value(val);
405	}
406	}
407
408	/* Handle +, - operators. */
409
410	static VALUE *eval3(void)
411	{
412	VALUE l, r;
413	int op;
414	arith_t val;
415
416	l = eval4();
417	while (1) {
418	if (nextarg("+"))
419	op = '+';
420	else if (nextarg("-"))
421	op = '-';
422	else
423	return l;
424	args++;
425	r = eval4();
426	val = arithmetic_common(l, r, op);
427	freev(l);
428	freev(r);
429	l = int_value(val);
430	}
431	}
432
433	/* Handle comparisons. */
434
435	static VALUE *eval2(void)
436	{
437	VALUE l, r;
438	int op;
439	arith_t val;
440
441	l = eval3();
442	while (1) {
443	if (nextarg("<"))
444	op = '<';
445	else if (nextarg("<="))
446	op = 'L' + 'E';
447	else if (nextarg("=") \|\| nextarg("=="))
448	op = '=';
449	else if (nextarg("!="))
450	op = '!';
451	else if (nextarg(">="))
452	op = 'G' + 'E';
453	else if (nextarg(">"))
454	op = '>';
455	else
456	return l;
457	args++;
458	r = eval3();
459	toarith(l);
460	toarith(r);
461	val = cmp_common(l, r, op);
462	freev(l);
463	freev(r);
464	l = int_value(val);
465	}
466	}
467
468	/* Handle &. */
469
470	static VALUE *eval1(void)
471	{
472	VALUE l, r;
473
474	l = eval2();
475	while (nextarg("&")) {
476	args++;
477	r = eval2();
478	if (null(l) \|\| null(r)) {
479	freev(l);
480	freev(r);
481	l = int_value(0);
482	} else
483	freev(r);
484	}
485	return l;
486	}
487
488	/* Handle \|. */
489
490	static VALUE *eval(void)
491	{
492	VALUE l, r;
493
494	l = eval1();
495	while (nextarg("\|")) {
496	args++;
497	r = eval1();
498	if (null(l)) {
499	freev(l);
500	l = r;
501	} else
502	freev(r);
503	}
504	return l;
505	}