/*
 * Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.truffle.sl.nodes;

import java.math.*;

import com.oracle.truffle.api.dsl.*;
import com.oracle.truffle.api.frame.*;
import com.oracle.truffle.api.nodes.*;
import com.oracle.truffle.sl.runtime.*;

/**
 * Base class for all SL nodes that produce a value and therefore benefit from type specialization.
 * The annotation {@Link TypeSystemReference} specifies the SL types. Specifying it here
 * defines the type system for all subclasses.
 */
@TypeSystemReference(SLTypes.class)
public abstract class SLExpressionNode extends SLStatementNode {

    /**
     * The execute method when no specialization is possible. This is the most general case,
     * therefore it must be provided by all subclasses.
     */
    public abstract Object executeGeneric(VirtualFrame frame);

    /**
     * When we use an expression at places where a {@SLStatmentNode statement} is
     * already sufficient, the return value is just discarded.
     */
    @Override
    public void executeVoid(VirtualFrame frame) {
        executeGeneric(frame);
    }

    /*
     * Execute methods for specialized types. They all follow the same pattern: they call the
     * generic execution method and then expect a result of their return type. Type-specialized
     * subclasses overwrite the appropriate methods.
     */

    public boolean executeBoolean(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectBoolean(executeGeneric(frame));
    }

    public long executeLong(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectLong(executeGeneric(frame));
    }

    public BigInteger executeBigInteger(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectBigInteger(executeGeneric(frame));
    }

    public String executeString(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectString(executeGeneric(frame));
    }

    public SLFunction executeFunction(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectSLFunction(executeGeneric(frame));
    }

    public SLNull executeNull(VirtualFrame frame) throws UnexpectedResultException {
        return SLTypesGen.SLTYPES.expectSLNull(executeGeneric(frame));
    }
}