54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
/* $Header$ */
|
|
/*
|
|
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
|
*/
|
|
/* s y m t a b . c
|
|
*
|
|
* Contains the routine findident, which builds the symbol table and
|
|
* searches identifiers
|
|
*/
|
|
# include "symtab.h"
|
|
|
|
struct symtab *idtable, *deftable;
|
|
|
|
struct symtab *
|
|
findident(s, mode, table) char *s; struct symtab **table; {
|
|
/*
|
|
* Look for identifier s in the symboltable referred to by *table.
|
|
* If mode = LOOKING, no new entry's will be made.
|
|
* If mode = ENTERING, a new entry will be made if s is not in the
|
|
* table yet, otherwise an error results
|
|
*/
|
|
char *malloc();
|
|
char *strcpy();
|
|
register struct symtab *p;
|
|
register n;
|
|
|
|
if (!*table) { /* No entry for this symbol */
|
|
if (mode == LOOKING) return (struct symtab *) 0;
|
|
/*
|
|
* Make new entry
|
|
*/
|
|
p = (struct symtab *) malloc(sizeof *p);
|
|
p->s_left = p->s_right = (struct symtab *) 0;
|
|
p->s_name = malloc( (unsigned) (strlen(s) + 1));
|
|
strcpy(p->s_name,s);
|
|
*table = p;
|
|
return p;
|
|
}
|
|
else {
|
|
p = *table;
|
|
if ((n = strcmp(p->s_name,s)) == 0) { /* This is it! */
|
|
if (mode == ENTERING) {
|
|
error("Identifier %s redefined",s);
|
|
}
|
|
return p;
|
|
}
|
|
/* Binary tree ..... */
|
|
if (n < 0) return findident(s,mode,&(p->s_left));
|
|
return findident(s,mode,&(p->s_right));
|
|
}
|
|
/* NOTREACHED */
|
|
}
|