ref: a852f55b6c9e9c374fe35fafe6cf1fdfeea7211a
dir: /sys/src/cmd/pic/symtab.c/
#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; */ }