ack/lang/m2/comp/lookup.c
1986-10-22 15:38:24 +00:00

78 lines
1.5 KiB
C

/* L O O K U P R O U T I N E S */
#include "debug.h"
#include <em_arith.h>
#include <em_label.h>
#include <assert.h>
#include "def.h"
#include "idf.h"
#include "scope.h"
#include "LLlex.h"
#include "node.h"
#include "type.h"
#include "misc.h"
struct def *
lookup(id, scope)
register struct idf *id;
struct scope *scope;
{
/* 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->next) { /* nothing */ }
if (df) {
/* Found it
*/
if (df1) {
/* Put the definition in front
*/
df1->next = df->next;
df->next = id->id_def;
id->id_def = df;
}
if (df->df_kind == D_IMPORT) {
assert(df->imp_def != 0);
return df->imp_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;
register struct scopelist *sc = vis;
while (sc) {
df = lookup(id->nd_IDF, sc->sc_scope);
if (df) return df;
sc = nextvisible(sc);
}
if (give_error) id_not_declared(id);
df = MkDef(id->nd_IDF, vis->sc_scope, D_ERROR);
df->df_type = error_type;
return df;
}