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