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	niro	532	/* 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			}