home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
minnie.tuhs.org
/
unixen.tar
/
unixen
/
PDP-11
/
Distributions
/
ucb
/
spencer_2bsd.tar.gz
/
2bsd.tar
/
src
/
pi0
/
lookup.c
< prev
next >
Wrap
C/C++ Source or Header
|
1980-02-17
|
2KB
|
116 lines
/* Copyright (c) 1979 Regents of the University of California */
#
/*
* pi - Pascal interpreter code translator
*
* Charles Haley, Bill Joy UCB
* Version 1.2 January 1979
*/
#include "0.h"
/*
* Lookup is called to
* find a symbol in the
* block structure symbol
* table and returns a pointer to
* its namelist entry.
*/
struct nl *lookup(s)
register char *s;
{
register struct nl *p;
register struct udinfo *udp;
if (s == NIL) {
nocascade();
return (NIL);
}
p = lookup1(s);
if (p == NIL) {
derror("%s is undefined", s);
return (NIL);
}
if (p->class == FVAR) {
p = p->chain;
bn--;
}
return (p);
}
#ifndef PI0
int flagwas;
#endif
/*
* Lookup1 is an internal lookup.
* It is not an error to call lookup1
* if the symbol is not defined. Also
* lookup1 will return FVARs while
* lookup never will, thus asgnop
* calls it when it thinks you are
* assigning to the function variable.
*/
lookup1(s)
register char *s;
{
register struct nl *p;
#ifndef PI0
register struct nl *q;
#endif
register int i;
if (s == NIL)
return (NIL);
bn = cbn;
#ifndef PI0
/*
* We first check the field names
* of the currently active with
* statements (expensive since they
* are not hashed).
*/
for (p = withlist; p != NIL; p = p->nl_next) {
q = p->type;
if (q == NIL)
continue;
if (reclook(q, s) != NIL)
/*
* Return the WITHPTR, lvalue understands.
*/
return (p);
}
#endif
/*
* Symbol table is a 64 way hash
* on the low bits of the character
* pointer value. (Simple, but effective)
*/
i = s & 077;
for (p = disptab[i]; p != NIL; p = p->nl_next)
if (p->symbol == s && p->class != FIELD && p->class != BADUSE) {
bn = (p->nl_block & 037);
#ifndef PI0
flagwas = p->nl_flags;
p->nl_flags =| NUSED;
#endif
return (p);
}
return (NIL);
}
#ifndef PI01
nlfund(sp)
char *sp;
{
register struct nl *p;
register int i;
i = sp & 077;
for (p = disptab[i]; p != NIL; p = p->nl_next)
if (p->symbol == sp && (p->nl_block & 037) == 0)
return (nloff(p));
return (0);
}
#endif