105 lines
2.2 KiB
C
105 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <string.h>
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#include "pic.h"
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#include "y.tab.h"
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YYSTYPE getvar(char *s) /* return value of variable s (usually pointer) */
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{
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struct symtab *p;
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static YYSTYPE bug;
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p = lookup(s);
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if (p == NULL) {
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if (islower(s[0]))
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ERROR "no such variable as %s", s WARNING;
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else
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ERROR "no such place as %s", s WARNING;
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return(bug);
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}
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return(p->s_val);
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}
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double getfval(char *s) /* return float value of variable s */
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{
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YYSTYPE y;
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y = getvar(s);
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return y.f;
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}
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void setfval(char *s, double f) /* set variable s to f */
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{
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struct symtab *p;
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if ((p = lookup(s)) != NULL)
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p->s_val.f = f;
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}
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struct symtab *makevar(char *s, int t, YYSTYPE v) /* make variable named s in table */
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/* assumes s is static or from tostring */
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{
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struct symtab *p;
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for (p = stack[nstack].p_symtab; p != NULL; p = p->s_next)
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if (strcmp(s, p->s_name) == 0)
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break;
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if (p == NULL) { /* it's a new one */
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p = (struct symtab *) malloc(sizeof(struct symtab));
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if (p == NULL)
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ERROR "out of symtab space with %s", s FATAL;
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p->s_next = stack[nstack].p_symtab;
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stack[nstack].p_symtab = p; /* stick it at front */
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}
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p->s_name = s;
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p->s_type = t;
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p->s_val = v;
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return(p);
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}
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struct symtab *lookup(char *s) /* find s in symtab */
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{
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int i;
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struct symtab *p;
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for (i = nstack; i >= 0; i--) /* look in each active symtab */
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for (p = stack[i].p_symtab; p != NULL; p = p->s_next)
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if (strcmp(s, p->s_name) == 0)
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return(p);
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return(NULL);
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}
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void freesymtab(struct symtab *p) /* free space used by symtab at p */
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{
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struct symtab *q;
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for ( ; p != NULL; p = q) {
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q = p->s_next;
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free(p->s_name); /* assumes done with tostring */
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free((char *)p);
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}
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}
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void freedef(char *s) /* free definition for string s */
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{
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struct symtab *p, *q, *op;
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for (p = op = q = stack[nstack].p_symtab; p != NULL; p = p->s_next) {
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if (strcmp(s, p->s_name) == 0) { /* got it */
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if (p->s_type != DEFNAME)
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break;
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if (p == op) /* 1st elem */
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stack[nstack].p_symtab = p->s_next;
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else
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q->s_next = p->s_next;
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free(p->s_name);
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free(p->s_val.p);
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free((char *)p);
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return;
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}
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q = p;
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}
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/* ERROR "%s is not defined at this point", s WARNING; */
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}
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