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Annotation of 43BSD/ucb/pascal/pdx/sym/predicates.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1980 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #ifndef lint
        !             8: static char sccsid[] = "@(#)predicates.c       5.1 (Berkeley) 6/6/85";
        !             9: #endif not lint
        !            10: /*
        !            11:  * The basic tests on a symbol.
        !            12:  */
        !            13: 
        !            14: #include "defs.h"
        !            15: #include "sym.h"
        !            16: #include "symtab.h"
        !            17: #include "btypes.h"
        !            18: #include "classes.h"
        !            19: #include "sym.rep"
        !            20: 
        !            21: /*
        !            22:  * Test if a symbol is a parameter.  This is true if there
        !            23:  * is a cycle from s->func to s via chain pointers.
        !            24:  */
        !            25: 
        !            26: BOOLEAN isparam(s)
        !            27: SYM *s;
        !            28: {
        !            29:     register SYM *t;
        !            30: 
        !            31:     for (t = s->func; t != NIL; t = t->chain) {
        !            32:        if (t == s) {
        !            33:            return(TRUE);
        !            34:        }
        !            35:     }
        !            36:     return(FALSE);
        !            37: }
        !            38: 
        !            39: /*
        !            40:  * Test if a symbol is a var parameter, i.e. has class REF.
        !            41:  */
        !            42: 
        !            43: BOOLEAN isvarparam(s)
        !            44: SYM *s;
        !            45: {
        !            46:     return (BOOLEAN) s->class == REF;
        !            47: }
        !            48: 
        !            49: /*
        !            50:  * Test if a symbol is a variable (actually any addressible quantity
        !            51:  * with do).
        !            52:  */
        !            53: 
        !            54: BOOLEAN isvariable(s)
        !            55: SYM *s;
        !            56: {
        !            57:     return s->class == VAR || s->class == FVAR || s->class == REF;
        !            58: }
        !            59: 
        !            60: /*
        !            61:  * Test if a symbol is a block, e.g. function, procedure, or the
        !            62:  * main program.
        !            63:  */
        !            64: 
        !            65: BOOLEAN isblock(s)
        !            66: register SYM *s;
        !            67: {
        !            68:     return(s->class == FUNC || s->class == PROC || s->class == PROG);
        !            69: }
        !            70: 
        !            71: /*
        !            72:  * Test if a symbol is builtin, that is, a predefined type or
        !            73:  * reserved word.
        !            74:  */
        !            75: 
        !            76: BOOLEAN isbuiltin(s)
        !            77: SYM *s;
        !            78: {
        !            79:     return(s->blkno == 0 && s->class != PROG && s->class != VAR);
        !            80: }
        !            81: 
        !            82: /*
        !            83:  * Compatible tests if two types are compatible.  The issue
        !            84:  * is complicated a bit by ranges.
        !            85:  *
        !            86:  * Integers and reals are not compatible since they cannot always be mixed.
        !            87:  */
        !            88: 
        !            89: BOOLEAN compatible(t1, t2)
        !            90: register SYM *t1, *t2;
        !            91: {
        !            92:     register BOOLEAN b;
        !            93: 
        !            94:     if (isvariable(t1)) {
        !            95:        t1 = t1->type;
        !            96:     }
        !            97:     if (isvariable(t2)) {
        !            98:        t2 = t2->type;
        !            99:     }
        !           100:     if (t1 == t2) {
        !           101:        b = TRUE;
        !           102:     } else {
        !           103:        t1 = rtype(t1);
        !           104:        t2 = rtype(t2);
        !           105:        if (t1->type == t2->type) {
        !           106:            if (t1->class == RANGE && t2->class == RANGE) {
        !           107:                b = TRUE;
        !           108:            } else if ((t1->class == SCAL || t1->class == CONST) &&
        !           109:              (t2->class == SCAL || t2->class == CONST)) {
        !           110:                b = TRUE;
        !           111:            } else if (t1->type == t_char &&
        !           112:              t1->class == ARRAY && t2->class == ARRAY) {
        !           113:                b = TRUE;
        !           114:            } else {
        !           115:                b = FALSE;
        !           116:            }
        !           117:     /*
        !           118:      * A kludge here for "nil".  Should be handled better.
        !           119:      * Opens a pandora's box for integer/pointer compatibility.
        !           120:      */
        !           121:        } else if ((t1->class == RANGE && t2->class == PTR) ||
        !           122:          (t2->class == RANGE && t1->class == PTR)) {
        !           123:            b = TRUE;
        !           124:        } else {
        !           125:            b = FALSE;
        !           126:        }
        !           127:     }
        !           128:     return b;
        !           129: }
        !           130: 
        !           131: /*
        !           132:  * Predicate to test if a symbol should be printed.  We don't print
        !           133:  * files, for example, simply because there's no good way to do it.
        !           134:  * The symbol must be within the given function.
        !           135:  */
        !           136: 
        !           137: BOOLEAN should_print(s, f)
        !           138: SYM *s;
        !           139: SYM *f;
        !           140: {
        !           141:     SYM *t;
        !           142: 
        !           143:     if (s->func != f || (s->class != VAR && s->class != FVAR)) {
        !           144:        return(FALSE);
        !           145:     } else if (s->chain != NIL) {
        !           146:        return(FALSE);
        !           147:     } else {
        !           148:        t = rtype(s->type);
        !           149:        if (t == NIL || t->class == FILET || t->class == SET) {
        !           150:            return(FALSE);
        !           151:        } else {
        !           152:            return(TRUE);
        !           153:        }
        !           154:     }
        !           155: }
        !           156: 
        !           157: /*
        !           158:  * Test if the name of a symbol is uniquely defined or not.
        !           159:  */
        !           160: 
        !           161: BOOLEAN isambiguous(s)
        !           162: SYM *s;
        !           163: {
        !           164:     SYM *t;
        !           165: 
        !           166:     t = st_lookup(symtab, s->symbol);
        !           167:     if (t == NIL) {
        !           168:        panic("symbol name vanished");
        !           169:     }
        !           170:     while (t != NIL && (s == t || !streq(t->symbol, s->symbol))) {
        !           171:        t = t->next_sym;
        !           172:     }
        !           173:     return t != NIL;
        !           174: }

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