/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <stdio.h>#include <stdlib.h>#include <ctype.h>#include <string.h>#include "pic.h"#include "y.tab.h" YYSTYPE getvar(char *s)	/* return value of variable s (usually pointer) */{	struct symtab *p;	static YYSTYPE bug; 	p = lookup(s);	if (p == NULL) {		if (islower(s[0]))			ERROR "no such variable as %s", s WARNING;		else			ERROR "no such place as %s", s WARNING;		return(bug);	}	return(p->s_val);} double getfval(char *s)	/* return float value of variable s */{	YYSTYPE y; 	y = getvar(s);	return y.f;} void setfval(char *s, double f)	/* set variable s to f */{	struct symtab *p; 	if ((p = lookup(s)) != NULL)		p->s_val.f = f;} struct symtab *makevar(char *s, int t, YYSTYPE v)	/* make variable named s in table */		/* assumes s is static or from tostring */{	struct symtab *p; 	for (p = stack[nstack].p_symtab; p != NULL; p = p->s_next)		if (strcmp(s, p->s_name) == 0)			break;	if (p == NULL) {	/* it's a new one */		p = (struct symtab *) malloc(sizeof(struct symtab));		if (p == NULL)			ERROR "out of symtab space with %s", s FATAL;		p->s_next = stack[nstack].p_symtab;		stack[nstack].p_symtab = p;	/* stick it at front */	}	p->s_name = s;	p->s_type = t;	p->s_val = v;	return(p);} struct symtab *lookup(char *s)	/* find s in symtab */{	int i;	struct symtab *p; 	for (i = nstack; i >= 0; i--)	/* look in each active symtab */		for (p = stack[i].p_symtab; p != NULL; p = p->s_next)			if (strcmp(s, p->s_name) == 0)				return(p);	return(NULL);} void freesymtab(struct symtab *p)	/* free space used by symtab at p */{	struct symtab *q; 	for ( ; p != NULL; p = q) {		q = p->s_next;		free(p->s_name);	/* assumes done with tostring */		free((char *)p);	}} void freedef(char *s)	/* free definition for string s */{	struct symtab *p, *q, *op; 	for (p = op = q = stack[nstack].p_symtab; p != NULL; p = p->s_next) {		if (strcmp(s, p->s_name) == 0) { 	/* got it */			if (p->s_type != DEFNAME)				break;			if (p == op)	/* 1st elem */				stack[nstack].p_symtab = p->s_next;			else				q->s_next = p->s_next;			free(p->s_name);			free(p->s_val.p);			free((char *)p);			return;		}		q = p;	}	/* ERROR "%s is not defined at this point", s WARNING; */}