b9e9314bd7
Fixed subtle bug wrt. comparing integers when either one hasn't been coersed from a string --- while avoiding an even subtler bug found in GNU expr.
531 lines
8.8 KiB
C
531 lines
8.8 KiB
C
/*
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* Copyright (c) 1993,94 Winning Strategies, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Winning Strategies, Inc.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <locale.h>
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#include <ctype.h>
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#include <regex.h>
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#include <err.h>
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enum token {
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OR, AND, EQ, LT, GT, ADD, SUB, MUL, DIV, MOD, MATCH, RP, LP,
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NE, LE, GE, OPERAND, EOI
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};
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struct val {
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enum {
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integer,
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string
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} type;
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union {
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char *s;
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int i;
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} u;
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};
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enum token token;
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struct val *tokval;
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char **av;
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struct val *
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make_int(i)
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int i;
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{
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struct val *vp;
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vp = (struct val *) malloc(sizeof(*vp));
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if (vp == NULL) {
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err(2, NULL);
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}
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vp->type = integer;
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vp->u.i = i;
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return vp;
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}
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struct val *
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make_str(s)
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char *s;
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{
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struct val *vp;
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vp = (struct val *) malloc(sizeof(*vp));
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if (vp == NULL || ((vp->u.s = strdup(s)) == NULL)) {
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err(2, NULL);
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}
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vp->type = string;
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return vp;
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}
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void
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free_value(vp)
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struct val *vp;
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{
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if (vp->type == string)
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free(vp->u.s);
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free(vp);
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}
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/* determine if vp is an integer; if so, return it's value in *r */
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int
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is_integer(vp, r)
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struct val *vp;
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int *r;
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{
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char *s;
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int neg;
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int i;
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if (vp->type == integer) {
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*r = vp->u.i;
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return 1;
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}
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/*
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* POSIX.2 defines an "integer" as an optional unary minus
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* followed by digits.
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*/
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s = vp->u.s;
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i = 0;
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neg = (*s == '-');
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if (neg)
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s++;
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while (*s) {
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if (!isdigit(*s))
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return 0;
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i *= 10;
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i += *s - '0';
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s++;
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}
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if (neg)
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i *= -1;
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*r = i;
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return 1;
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}
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/* coerce to vp to an integer */
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int
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to_integer(vp)
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struct val *vp;
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{
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int r;
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if (vp->type == integer)
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return 1;
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if (is_integer(vp, &r)) {
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free(vp->u.s);
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vp->u.i = r;
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vp->type = integer;
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return 1;
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}
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return 0;
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}
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/* coerce to vp to an string */
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void
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to_string(vp)
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struct val *vp;
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{
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char *tmp;
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if (vp->type == string)
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return;
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tmp = malloc(25);
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if (tmp == NULL) {
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err(2, NULL);
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}
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sprintf(tmp, "%d", vp->u.i);
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vp->type = string;
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vp->u.s = tmp;
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}
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int
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is_zero_or_null(vp)
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struct val *vp;
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{
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if (vp->type == integer) {
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return (vp->u.i == 0);
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} else {
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return (*vp->u.s == 0 || (to_integer(vp) && vp->u.i == 0));
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}
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/* NOTREACHED */
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}
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void
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nexttoken()
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{
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char *p;
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if ((p = *av) == NULL) {
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token = EOI;
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return;
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}
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av++;
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if (p[0] != '\0') {
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if (p[1] == '\0') {
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const char *x = "|&=<>+-*/%:()";
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char *i; /* index */
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if ((i = strchr(x, *p)) != NULL) {
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token = i - x;
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return;
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}
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} else if (p[1] == '=' && p[2] == '\0') {
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switch (*p) {
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case '<':
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token = LE;
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return;
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case '>':
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token = GE;
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return;
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case '!':
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token = NE;
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return;
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}
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}
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}
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tokval = make_str(p);
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token = OPERAND;
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return;
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}
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void
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error()
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{
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errx(2, "syntax error");
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/* NOTREACHED */
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}
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struct val *
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eval6()
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{
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struct val *eval0 __P((void));
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struct val *v;
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if (token == OPERAND) {
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nexttoken();
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return tokval;
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} else if (token == RP) {
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nexttoken();
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v = eval0();
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if (token != LP) {
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error();
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/* NOTREACHED */
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}
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nexttoken();
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return v;
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} else {
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error();
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}
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/* NOTREACHED */
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}
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/* Parse and evaluate match (regex) expressions */
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struct val *
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eval5()
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{
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regex_t rp;
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regmatch_t rm[2];
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char errbuf[256];
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int eval;
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struct val *l, *r;
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struct val *v;
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l = eval6();
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while (token == MATCH) {
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nexttoken();
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r = eval6();
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/* coerce to both arguments to strings */
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to_string(l);
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to_string(r);
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/* compile regular expression */
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if ((eval = regcomp(&rp, r->u.s, 0)) != 0) {
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regerror(eval, &rp, errbuf, sizeof(errbuf));
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errx(2, "%s", errbuf);
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}
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/* compare string against pattern -- remember that patterns
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are anchored to the beginning of the line */
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if (regexec(&rp, l->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
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if (rm[1].rm_so >= 0) {
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*(l->u.s + rm[1].rm_eo) = '\0';
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v = make_str(l->u.s + rm[1].rm_so);
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} else {
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v = make_int((int)(rm[0].rm_eo - rm[0].rm_so));
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}
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} else {
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if (rp.re_nsub == 0) {
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v = make_int(0);
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} else {
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v = make_str("");
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}
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}
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/* free arguments and pattern buffer */
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free_value(l);
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free_value(r);
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regfree(&rp);
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l = v;
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}
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return l;
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}
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/* Parse and evaluate multiplication and division expressions */
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struct val *
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eval4()
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{
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struct val *l, *r;
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enum token op;
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l = eval5();
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while ((op = token) == MUL || op == DIV || op == MOD) {
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nexttoken();
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r = eval5();
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if (!to_integer(l) || !to_integer(r)) {
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errx(2, "non-numeric argument");
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}
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if (op == MUL) {
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l->u.i *= r->u.i;
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} else {
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if (r->u.i == 0) {
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errx(2, "division by zero");
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}
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if (op == DIV) {
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l->u.i /= r->u.i;
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} else {
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l->u.i %= r->u.i;
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}
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}
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free_value(r);
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}
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return l;
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}
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/* Parse and evaluate addition and subtraction expressions */
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struct val *
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eval3()
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{
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struct val *l, *r;
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enum token op;
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l = eval4();
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while ((op = token) == ADD || op == SUB) {
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nexttoken();
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r = eval4();
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if (!to_integer(l) || !to_integer(r)) {
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errx(2, "non-numeric argument");
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}
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if (op == ADD) {
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l->u.i += r->u.i;
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} else {
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l->u.i -= r->u.i;
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}
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free_value(r);
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}
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return l;
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}
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/* Parse and evaluate comparison expressions */
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struct val *
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eval2()
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{
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struct val *l, *r;
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enum token op;
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int v, li, ri;
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l = eval3();
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while ((op = token) == EQ || op == NE || op == LT || op == GT || op == LE || op == GE) {
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nexttoken();
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r = eval3();
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if (is_integer(l, &li) && is_integer(r, &ri)) {
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switch (op) {
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case GT:
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v = (li > ri);
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break;
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case GE:
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v = (li >= ri);
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break;
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case LT:
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v = (li < ri);
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break;
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case LE:
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v = (li <= ri);
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break;
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case EQ:
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v = (li == ri);
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break;
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case NE:
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v = (li != ri);
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break;
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}
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} else {
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to_string(l);
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to_string(r);
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switch (op) {
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case GT:
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v = (strcoll(l->u.s, r->u.s) > 0);
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break;
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case GE:
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v = (strcoll(l->u.s, r->u.s) >= 0);
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break;
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case LT:
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v = (strcoll(l->u.s, r->u.s) < 0);
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break;
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case LE:
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v = (strcoll(l->u.s, r->u.s) <= 0);
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break;
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case EQ:
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v = (strcoll(l->u.s, r->u.s) == 0);
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break;
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case NE:
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v = (strcoll(l->u.s, r->u.s) != 0);
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break;
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}
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}
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free_value(l);
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free_value(r);
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l = make_int(v);
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}
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return l;
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}
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/* Parse and evaluate & expressions */
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struct val *
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eval1()
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{
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struct val *l, *r;
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l = eval2();
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while (token == AND) {
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nexttoken();
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r = eval2();
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if (is_zero_or_null(l) || is_zero_or_null(r)) {
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free_value(l);
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free_value(r);
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l = make_int(0);
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} else {
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free_value(r);
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}
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}
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return l;
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}
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/* Parse and evaluate | expressions */
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struct val *
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eval0()
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{
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struct val *l, *r;
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l = eval1();
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while (token == OR) {
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nexttoken();
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r = eval1();
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if (is_zero_or_null(l)) {
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free_value(l);
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l = r;
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} else {
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free_value(r);
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}
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}
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return l;
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}
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int
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main(argc, argv)
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int argc;
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char **argv;
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{
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struct val *vp;
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if (!setlocale(LC_ALL, "")) {
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fprintf(stderr,
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"setlocale failed, continuing with \"C\" locale.");
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}
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av = argv + 1;
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nexttoken();
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vp = eval0();
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if (token != EOI) {
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error();
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/* NOTREACHED */
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}
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if (vp->type == integer)
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printf("%d\n", vp->u.i);
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else
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printf("%s\n", vp->u.s);
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exit(is_zero_or_null(vp));
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}
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