ack/lang/pc/comp/lookup.c
2006-02-04 00:57:05 +00:00

113 lines
2.4 KiB
C

/* L O O K U P R O U T I N E S */
#include <alloc.h>
#include <em_arith.h>
#include <em_label.h>
#include <assert.h>
#include "LLlex.h"
#include "def.h"
#include "idf.h"
#include "misc.h"
#include "node.h"
#include "scope.h"
#include "type.h"
remove_def(df)
register struct def *df;
{
struct idf *id= df->df_idf;
struct def *df1 = id->id_def;
if( df1 == df ) id->id_def = df->df_next;
else {
while( df1 && df1->df_next != df ) df1 = df1->df_next;
df1->df_next = df->df_next;
}
free_def(df);
}
struct def *
lookup(id, scope, inuse)
register struct idf *id;
struct scope *scope;
long inuse;
{
/* Look up a definition of an identifier in scope "scope".
Make the "def" list self-organizing.
Return a pointer to its "def" structure if it exists,
otherwise return 0.
*/
register struct def *df, *df1;
/* Look in the chain of definitions of this "id" for one with scope
"scope".
*/
for( df = id->id_def, df1 = 0;
df && df->df_scope != scope;
df1 = df, df = df->df_next ) { /* nothing */ }
if( df ) {
/* Found it
*/
if( df1) {
/* Put the definition in front
*/
df1->df_next = df->df_next;
df->df_next = id->id_def;
id->id_def = df;
}
while( df->df_kind & inuse ) {
assert(df->usd_def != 0);
df=df->usd_def;
}
}
return df;
}
struct def *
lookfor(id, vis, give_error)
register struct node *id;
struct scopelist *vis;
{
/* Look for an identifier in the visibility range started by "vis".
If it is not defined create a dummy definition and
if give_error is set, give an error message.
*/
register struct def *df, *tmp_df;
register struct scopelist *sc = vis;
while( sc ) {
df = lookup(id->nd_IDF, sc->sc_scope, D_INUSE);
if( df ) {
while( vis->sc_scope->sc_level >
sc->sc_scope->sc_level ) {
if( tmp_df = define(id->nd_IDF, vis->sc_scope,
D_INUSE))
tmp_df->usd_def = df;
vis = nextvisible(vis);
}
/* Since the scope-level of standard procedures is the
* same as for the user-defined procedures, the procedure
* must be marked as used. Not doing so would mean that
* such a procedure could redefined after usage.
*/
if( (vis->sc_scope == GlobalScope) &&
!lookup(id->nd_IDF, GlobalScope, D_INUSE) ) {
if( tmp_df = define(id->nd_IDF, vis->sc_scope,
D_INUSE))
tmp_df->usd_def = df;
}
return df;
}
sc = nextvisible(sc);
}
if( give_error ) id_not_declared(id);
df = MkDef(id->nd_IDF, vis->sc_scope, D_ERROR);
return df;
}