/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is TransforMiiX XSLT processor.
 * 
 * The Initial Developer of the Original Code is The MITRE Corporation.
 * Portions created by MITRE are Copyright (C) 1999 The MITRE Corporation.
 *
 * Portions created by Keith Visco as a Non MITRE employee,
 * (C) 1999 Keith Visco. All Rights Reserved.
 * 
 * Contributor(s): 
 * Keith Visco, kvisco@ziplink.net
 *   -- original author.
 *    
 * $Id: RootExpr.cpp,v 1.1 2000-04-06 07:45:39 kvisco%ziplink.net Exp $
 */

#include "Expr.h"

MBool RootExpr::isAbsolute() {
    return MB_TRUE;
} //-- isAbsolute

/**
 * Evaluates this Expr based on the given context node and processor state
 * @param context the context node for evaluation of this Expr
 * @param ps the ContextState containing the stack information needed
 * for evaluation
 * @return the result of the evaluation
**/
ExprResult* RootExpr::evaluate(Node* context, ContextState* cs) {
    NodeSet* nodeSet = new NodeSet();
    if ( !context ) return nodeSet;
    nodeSet->add(context->getOwnerDocument());
    return nodeSet;
} //-- evaluate

/**
 * Returns the default priority of this Pattern based on the given Node,
 * context Node, and ContextState.
 * If this pattern does not match the given Node under the current context Node and
 * ContextState then Negative Infinity is returned.
**/
double RootExpr::getDefaultPriority(Node* node, Node* context, ContextState* cs) {
    if ( matches(node, context, cs) ) {
        return 0.5;
    }
    else return Double::NEGATIVE_INFINITY;
} //-- getDefaultPriority

/**
 * Determines whether this NodeExpr matches the given node within
 * the given context
**/
MBool RootExpr::matches(Node* node, Node* context, ContextState* cs) {
    if ( node ) {
        return (MBool) (node->getNodeType() == Node::DOCUMENT_NODE);
    }
    return MB_FALSE;
} //-- matches

/**
 * Returns the String representation of this PatternExpr.
 * @param dest the String to use when creating the String
 * representation. The String representation will be appended to
 * any data in the destination String, to allow cascading calls to
 * other #toString() methods for Expressions.
 * @return the String representation of this PatternExpr.
**/
void RootExpr::toString(String& dest) {
    dest.append('/');
} //-- toString