/*
 * Copyright (c) 2003
 *      David Leonard.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of David Leonard nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/* $Id: scope.c 1282 2007-09-13 22:26:35Z d $ */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include <see/object.h>
#include <see/value.h>
#include <see/native.h>
#include <see/debug.h>
#include <see/string.h>
#include <see/eval.h>

#include "scope.h"
#include "dprint.h"

#ifndef NDEBUG
int SEE_scope_debug = 0;
#endif

/*
 * Used in the 'PrimaryExpression: Identifier' production
 * to resolve an identifier within an execution context.
 * Returns a reference.
 * -- 10.1.4
 */
void
SEE_scope_lookup(interp, scope, ident, res)
	struct SEE_interpreter *interp;
	struct SEE_scope *scope;
	struct SEE_string *ident; 
	struct SEE_value *res;
{

	for (; scope; scope = scope->next) {

#ifndef NDEBUG
	    if (SEE_scope_debug) {
		dprintf("scope_lookup: searching for '");
		dprints(ident);
		dprintf("' in scope %p, obj = ", scope);
		dprinto(interp, scope->obj);
		dprintf("\n");
	    }
#endif

	    if (SEE_OBJECT_HASPROPERTY(interp, scope->obj, ident)) {
		_SEE_SET_REFERENCE(res, scope->obj, ident);
#ifndef NDEBUG
	        if (SEE_scope_debug) {
		    dprintf("SEE_scope_lookup: found '");
		    dprints(ident);
		    dprintf("' in ");
		    dprinto(interp, scope->obj);
		    dprintf("\n");
	        }
#endif
		return;
	    }
	}

#ifndef NDEBUG
	if (SEE_scope_debug) {
	    dprintf("SEE_scope_lookup: not found: '");
	    dprints(ident);
	    dprintf("'\n");
	}
#endif

	_SEE_SET_REFERENCE(res, NULL, ident);
}

/*
 * Return false if the two scopes have observable difference.
 * In some cases, (esp. mutually recursion) this simple test
 * will incorrectly return false. Simple scope recursion is handled OK.
 */
int
SEE_scope_eq(s1, s2)
	struct SEE_scope *s1, *s2;
{
	struct SEE_object *o;

	while (s1 && s2) {
	    if (s1 == s2)
		return 1;
	    if (!SEE_OBJECT_JOINED(s1->obj, s2->obj))
		return 0;

	    /* Advance down the scope chains, skipping duplicates */
	    o = s1->obj;
	    do {
		    s1 = s1->next;
	    } while (s1 && SEE_OBJECT_JOINED(s1->obj, o));
	    o = s2->obj;
	    do {
		    s2 = s2->next;
	    } while (s2 && SEE_OBJECT_JOINED(s2->obj, o));
	}
	return s1 == s2;
}

