modula-2.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*#@(#)modula-2.c	4.2  Ultrix  11/9/90*/

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *									*
 *			Modification History				*
 *									*
 *	002 - Merged in 4.3 changes.					*
 *	      (vjh, April 29, 1986)					*
 *									*
 *	001 - Modified modula2_init() to use LanguageName constant in 	*
 *	      call to language_define().				*
 *	      (Victoria Holt, June 22, 1985)				*
 *									*
 ************************************************************************/

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)modula-2.c	5.1 (Berkeley) 5/31/85";
#endif not lint

/*
 * Modula-2 specific symbol routines.
 */

#include "defs.h"
#include "symbols.h"
#include "modula-2.h"
#include "languages.h"
#include "tree.h"
#include "eval.h"
#include "mappings.h"
#include "process.h"
#include "runtime.h"
#include "machine.h"

#ifndef public
#endif

private Language mod2;
private boolean initialized;


#define ischar(t) ( \
    (t) == t_char->type or \
    ((t)->class == RANGE and istypename((t)->type, "char")) \
)

/*
 * Initialize Modula-2 information.
 */

public modula2_init ()
{
    mod2 = language_define("modula-2", MODULA2);
    language_setop(mod2, L_PRINTDECL, modula2_printdecl);
    language_setop(mod2, L_PRINTVAL, modula2_printval);
    language_setop(mod2, L_TYPEMATCH, modula2_typematch);
    language_setop(mod2, L_BUILDAREF, modula2_buildaref);
    language_setop(mod2, L_EVALAREF, modula2_evalaref);
    language_setop(mod2, L_MODINIT, modula2_modinit);
    language_setop(mod2, L_HASMODULES, modula2_hasmodules);
    language_setop(mod2, L_PASSADDR, modula2_passaddr);
    initialized = false;
}

/*
 * Typematch tests if two types are compatible.  The issue
 * is a bit complicated, so several subfunctions are used for
 * various kinds of compatibility.
 */

private boolean builtinmatch (t1, t2)
register Symbol t1, t2;
{
    boolean b;

    b = (boolean) (
	(
	    t2 == t_int->type and t1->class == RANGE and
	    (
		istypename(t1->type, "integer") or
		istypename(t1->type, "cardinal")
	    )
	) or (
	    t2 == t_char->type and
	    t1->class == RANGE and istypename(t1->type, "char")
	) or (
	    t2 == t_real->type and
	    t1->class == RANGE and (
		istypename(t1->type, "real") or
		istypename(t1->type, "longreal")
	    )
	) or (
	    t2 == t_boolean->type and
	    t1->class == RANGE and istypename(t1->type, "boolean")
	)
    );
    return b;
}

private boolean rangematch (t1, t2)
register Symbol t1, t2;
{
    boolean b;
    register Symbol rt1, rt2;

    if (t1->class == RANGE and t2->class == RANGE) {
	b = (boolean) (
	    t1->symvalue.rangev.lower == t2->symvalue.rangev.lower and
	    t1->symvalue.rangev.upper == t2->symvalue.rangev.upper
	);
    } else {
	b = false;
    }
    return b;
}

private boolean nilMatch (t1, t2)
register Symbol t1, t2;
{
    boolean b;

    b = (boolean) (
	(t1 == t_nil and t2->class == PTR) or
	(t1->class == PTR and t2 == t_nil)
    );
    return b;
}

private boolean enumMatch (t1, t2)
register Symbol t1, t2;
{
    boolean b;

    b = (boolean) (
	(t1->class == SCAL and t2->class == CONST and t2->type == t1) or
	(t1->class == CONST and t2->class == SCAL and t1->type == t2)
    );
    return b;
}

private boolean openArrayMatch (t1, t2)
register Symbol t1, t2;
{
    boolean b;

    b = (boolean) (
	(
	    t1->class == DYNARRAY and t1->symvalue.ndims == 1 and
	    t2->class == ARRAY and
	    compatible(rtype(t2->chain)->type, t_int) and
	    compatible(t1->type, t2->type)
	) or (
	    t2->class == DYNARRAY and t2->symvalue.ndims == 1 and
	    t1->class == ARRAY and
	    compatible(rtype(t1->chain)->type, t_int) and
	    compatible(t1->type, t2->type)
	)
    );
    return b;
}

private boolean isConstString (t)
register Symbol t;
{
    boolean b;

    b = (boolean) (
	t->language == primlang and t->class == ARRAY and t->type == t_char
    );
    return b;
}

private boolean stringArrayMatch (t1, t2)
register Symbol t1, t2;
{
    boolean b;

    b = (boolean) (
	(
	    isConstString(t1) and
	    t2->class == ARRAY and compatible(t2->type, t_char->type)
	) or (
	    isConstString(t2) and
	    t1->class == ARRAY and compatible(t1->type, t_char->type)
	)
    );
    return b;
}

public boolean modula2_typematch (type1, type2)
Symbol type1, type2;
{
    boolean b;
    Symbol t1, t2, tmp;

    t1 = rtype(type1);
    t2 = rtype(type2);
    if (t1 == t2) {
	b = true;
    } else {
	if (t1 == t_char->type or t1 == t_int->type or
	    t1 == t_real->type or t1 == t_boolean->type
	) {
	    tmp = t1;
	    t1 = t2;
	    t2 = tmp;
	}
	b = (Boolean) (
	    builtinmatch(t1, t2) or rangematch(t1, t2) or
	    nilMatch(t1, t2) or enumMatch(t1, t2) or
	    openArrayMatch(t1, t2) or stringArrayMatch(t1, t2)
	);
    }
    return b;
}

/*
 * Indent n spaces.
 */

private indent (n)
int n;
{
    if (n > 0) {
	printf("%*c", n, ' ');
    }
}

public modula2_printdecl (s)
Symbol s;
{
    register Symbol t;
    Boolean semicolon;

    semicolon = true;
    if (s->class == TYPEREF) {
	resolveRef(t);
    }
    switch (s->class) {
	case CONST:
	    if (s->type->class == SCAL) {
		semicolon = false;
		printf("enumeration constant with value ");
		eval(s->symvalue.constval);
		modula2_printval(s);
	    } else {
		printf("const %s = ", symname(s));
		eval(s->symvalue.constval);
		modula2_printval(s);
	    }
	    break;

	case TYPE:
	    printf("type %s = ", symname(s));
	    printtype(s, s->type, 0);
	    break;

	case TYPEREF:
	    printf("type %s", symname(s));
	    break;

	case VAR:
	    if (isparam(s)) {
		printf("(parameter) %s : ", symname(s));
	    } else {
		printf("var %s : ", symname(s));
	    }
	    printtype(s, s->type, 0);
	    break;

	case REF:
	    printf("(var parameter) %s : ", symname(s));
	    printtype(s, s->type, 0);
	    break;

	case RANGE:
	case ARRAY:
	case DYNARRAY:
	case SUBARRAY:
	case RECORD:
	case VARNT:
	case PTR:
	    printtype(s, s, 0);
	    semicolon = false;
	    break;

	case FVAR:
	    printf("(function variable) %s : ", symname(s));
	    printtype(s, s->type, 0);
	    break;

	case FIELD:
	    printf("(field) %s : ", symname(s));
	    printtype(s, s->type, 0);
	    break;

	case PROC:
	    printf("procedure %s", symname(s));
	    listparams(s);
	    break;

	case PROG:
	    printf("program %s", symname(s));
	    listparams(s);
	    break;

	case FUNC:
	    printf("procedure %s", symname(s));
	    listparams(s);
	    printf(" : ");
	    printtype(s, s->type, 0);
	    break;

	case MODULE:
	    printf("module %s", symname(s));
	    break;

	default:
	    printf("[%s]", classname(s));
	    break;
    }
    if (semicolon) {
	putchar(';');
    }
    putchar('\n');
}

/*
 * Recursive whiz-bang procedure to print the type portion
 * of a declaration.
 *
 * The symbol associated with the type is passed to allow
 * searching for type names without getting "type blah = blah".
 */

private printtype (s, t, n)
Symbol s;
Symbol t;
int n;
{
    Symbol tmp;
    int i;

    if (t->class == TYPEREF) {
	resolveRef(t);
    }
    switch (t->class) {
	case VAR:
	case CONST:
	case FUNC:
	case PROC:
	    panic("printtype: class %s", classname(t));
	    break;

	case ARRAY:
	    printf("array[");
	    tmp = t->chain;
	    if (tmp != nil) {
		for (;;) {
		    printtype(tmp, tmp, n);
		    tmp = tmp->chain;
		    if (tmp == nil) {
			break;
		    }
		    printf(", ");
		}
	    }
	    printf("] of ");
	    printtype(t, t->type, n);
	    break;

	case DYNARRAY:
	    printf("dynarray of ");
	    for (i = 1; i < t->symvalue.ndims; i++) {
		printf("array of ");
	    }
	    printtype(t, t->type, n);
	    break;

	case SUBARRAY:
	    printf("subarray of ");
	    for (i = 1; i < t->symvalue.ndims; i++) {
		printf("array of ");
	    }
	    printtype(t, t->type, n);
	    break;

	case RECORD:
	    printRecordDecl(t, n);
	    break;

	case FIELD:
	    if (t->chain != nil) {
		printtype(t->chain, t->chain, n);
	    }
	    printf("\t%s : ", symname(t));
	    printtype(t, t->type, n);
	    printf(";\n");
	    break;

	case RANGE:
	    printRangeDecl(t);
	    break;

	case PTR:
	    printf("pointer to ");
	    printtype(t, t->type, n);
	    break;

	case TYPE:
	    if (t->name != nil and ident(t->name)[0] != '\0') {
		printname(stdout, t);
	    } else {
		printtype(t, t->type, n);
	    }
	    break;

	case SCAL:
	    printEnumDecl(t, n);
	    break;

	case SET:
	    printf("set of ");
	    printtype(t, t->type, n);
	    break;

	case TYPEREF:
	    break;

	case FPROC:
	case FFUNC:
	    printf("procedure");
	    break;

	default:
	    printf("[%s]", classname(t));
	    break;
    }
}

/*
 * Print out a record declaration.
 */

private printRecordDecl (t, n)
Symbol t;
int n;
{
    register Symbol f;

    if (t->chain == nil) {
	printf("record end");
    } else {
	printf("record\n");
	for (f = t->chain; f != nil; f = f->chain) {
	    indent(n+4);
	    printf("%s : ", symname(f));
	    printtype(f->type, f->type, n+4);
	    printf(";\n");
	}
	indent(n);
	printf("end");
    }
}

/*
 * Print out the declaration of a range type.
 */

private printRangeDecl (t)
Symbol t;
{
    long r0, r1;

    r0 = t->symvalue.rangev.lower;
    r1 = t->symvalue.rangev.upper;
    if (ischar(t)) {
	if (r0 < 0x20 or r0 > 0x7e) {
	    printf("%ld..", r0);
	} else {
	    printf("'%c'..", (char) r0);
	}
	if (r1 < 0x20 or r1 > 0x7e) {
	    printf("\\%lo", r1);
	} else {
	    printf("'%c'", (char) r1);
	}
    } else if (r0 > 0 and r1 == 0) {
	printf("%ld byte real", r0);
    } else if (r0 >= 0) {
	printf("%lu..%lu", r0, r1);
    } else {
	printf("%ld..%ld", r0, r1);
    }
}

/*
 * Print out an enumeration declaration.
 */

private printEnumDecl (e, n)
Symbol e;
int n;
{
    Symbol t;

    printf("(");
    t = e->chain;
    if (t != nil) {
	printf("%s", symname(t));
	t = t->chain;
	while (t != nil) {
	    printf(", %s", symname(t));
	    t = t->chain;
	}
    }
    printf(")");
}

/*
 * List the parameters of a procedure or function.
 * No attempt is made to combine like types.
 */

private listparams (s)
Symbol s;
{
    Symbol t;

    if (s->chain != nil) {
	putchar('(');
	for (t = s->chain; t != nil; t = t->chain) {
	    switch (t->class) {
		case REF:
		    printf("var ");
		    break;

		case FPROC:
		case FFUNC:
		    printf("procedure ");
		    break;

		case VAR:
		    break;

		default:
		    panic("unexpected class %d for parameter", t->class);
	    }
	    printf("%s", symname(t));
	    if (s->class == PROG) {
		printf(", ");
	    } else {
		printf(" : ");
		printtype(t, t->type, 0);
		if (t->chain != nil) {
		    printf("; ");
		}
	    }
	}
	putchar(')');
    }
}

/*
 * Test if a pointer type should be treated as a null-terminated string.
 * The type given is the type that is pointed to.
 */

private boolean isCstring (type)
Symbol type;
{
    boolean b;
    register Symbol a, t;

    a = rtype(type);
    if (a->class == ARRAY) {
	t = rtype(a->chain);
	b = (boolean) (
	    t->class == RANGE and istypename(a->type, "char") and
	    (t->symvalue.rangev.upper - t->symvalue.rangev.lower + 1) <= 0
	);
    } else {
	b = false;
    }
    return b;
}

/*
 * Modula 2 interface to printval.
 */