/*

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (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.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.InstructionList;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodType;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

/**

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 */

final class UnaryOpExpr extends Expression {

    private Expression _left;

    public UnaryOpExpr(Expression left) {

        (_left = left).setParent(this);

    }

    /**

     * Returns true if this expressions contains a call to position(). This is

     * needed for context changes in node steps containing multiple predicates.

     */

    public boolean hasPositionCall() {

        return(_left.hasPositionCall());

    }

    /**

     * Returns true if this expressions contains a call to last()

     */

    public boolean hasLastCall() {

            return(_left.hasLastCall());

    }

    public void setParser(Parser parser) {

        super.setParser(parser);

        _left.setParser(parser);

    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {

        final Type tleft = _left.typeCheck(stable);

        final MethodType ptype = lookupPrimop(stable, "u-",

                                              new MethodType(Type.Void,

                                                             tleft));

        if (ptype != null) {

            if (!arg1.identicalTo(tleft)) {

                _left = new CastExpr(_left, arg1);

            }

            return _type = ptype.resultType();

        }

        throw new TypeCheckError(this);

    }

    public String toString() {

        return "u-" + '(' + _left + ')';

    }

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

        InstructionList il = methodGen.getInstructionList();

        _left.translate(classGen, methodGen);

        il.append(_type.NEG());

    }

}