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Annotation of 42BSD/ucb/pascal/pdx/sym/which.c, revision 1.1.1.1

1.1       root        1: /* Copyright (c) 1982 Regents of the University of California */
                      2: 
                      3: static char sccsid[] = "@(#)which.c 1.1 1/18/82";
                      4: 
                      5: /*
                      6:  * Routines to distinguish symbols of the same name.
                      7:  */
                      8: 
                      9: #include "defs.h"
                     10: #include "sym.h"
                     11: #include "classes.h"
                     12: #include "symtab.h"
                     13: #include "mappings.h"
                     14: #include "machine.h"
                     15: #include "sym.rep"
                     16: 
                     17: /*
                     18:  * Figure out the "current" symbol being referred to,
                     19:  * this is either the active one or the most visible from the
                     20:  * current scope.
                     21:  *
                     22:  * Fields are purposely ignored; these can be gotten to via "findclass".
                     23:  */
                     24: 
                     25: SYM *which(s)
                     26: SYM *s;
                     27: {
                     28:        register SYM *p, *t, *f;
                     29: 
                     30:        if (s == program || isbuiltin(s)) {
                     31:                return(s);
                     32:        }
                     33:        if (!isactive(program)) {
                     34:                f = program;
                     35:        } else {
                     36:                f = whatblock(pc);
                     37:                if (f == NIL) {
                     38:                        panic("no block for addr 0x%x", pc);
                     39:                }
                     40:        }
                     41:        for (p = f; p != NIL; p = p->func) {
                     42:                if ((t = findsym(s, p)) != NIL) {
                     43:                        break;
                     44:                }
                     45:        }
                     46:        if (t == NIL) {
                     47:                error("\"%s\" is not known in \"%s\"", s->symbol, f->symbol);
                     48:        }
                     49:        return(t);
                     50: }
                     51: 
                     52: /*
                     53:  * Find a (non-field) symbol with name s->symbol belonging to block f.
                     54:  *
                     55:  * Parameters to the main program are purposely "not found" because
                     56:  * pi gives them no type.
                     57:  */
                     58: 
                     59: SYM *findsym(s, f)
                     60: SYM *s;
                     61: SYM *f;
                     62: {
                     63:        register SYM *t;
                     64: 
                     65:        if (!isblock(f)) {
                     66:                error("%s is not a block", f->symbol);
                     67:        }
                     68:        for (t = s; t != NIL; t = t->next_sym) {
                     69:                if (t->func == f && !(f == program && isparam(t)) &&
                     70:                  t->class != FIELD && streq(t->symbol, s->symbol)) {
                     71:                        break;
                     72:                }
                     73:        }
                     74:        return(t);
                     75: }
                     76: 
                     77: /*
                     78:  * Find the symbol which is has the same name and scope as the
                     79:  * given symbol but is of the given field.  Return NIL if there is none.
                     80:  */
                     81: 
                     82: SYM *findclass(s, cl)
                     83: SYM *s;
                     84: char cl;
                     85: {
                     86:        register SYM *t;
                     87: 
                     88:        if (s->class == cl) {
                     89:                return(s);
                     90:        }
                     91:        t = st_lookup(symtab, s->symbol);
                     92:        while (t != NIL && (t->class != cl || t->func != s->func ||
                     93:          !streq(s->symbol, t->symbol))) {
                     94:                t = t->next_sym;
                     95:        }
                     96:        return(t);
                     97: }

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