org.btrplace.btrpsl.tree.SelfAssignmentStatement Maven / Gradle / Ivy

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/*
 * Copyright (c) 2016 University Nice Sophia Antipolis
 *
 * This file is part of btrplace.
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 */

package org.btrplace.btrpsl.tree;

import org.antlr.runtime.Token;
import org.btrplace.btrpsl.ErrorReporter;
import org.btrplace.btrpsl.SymbolsTable;
import org.btrplace.btrpsl.antlr.ANTLRBtrplaceSL2Parser;
import org.btrplace.btrpsl.element.BtrpOperand;
import org.btrplace.btrpsl.element.IgnorableOperand;

/**
 * A parser to declare a variable.
 *
 * @author Fabien Hermenier
 */
public class SelfAssignmentStatement extends BtrPlaceTree {

    /**
     * The operation.
     */
    public enum Type {
        /**
         * +=
         */PLUS_EQUALS,
        /**
         * -=
         */MINUS_EQUALS,
        /**
         * /=
         */DIV_EQUALS,
        /**
         * %=
         */REMAINDER_EQUALS,
        /**
         * =
         */TIMES_EQUALS
    }

    private Type type;

    /**
     * The table of symbols to use;
     */
    private SymbolsTable symbols;

    /**
     * Make a new parser
     *
     * @param t    the root token
     * @param errs the errors to report
     */
    public SelfAssignmentStatement(Type t, Token tok, ErrorReporter errs, SymbolsTable syms) {
        super(tok, errs);
        this.type = t;
        this.symbols = syms;
    }

    @Override
    public BtrpOperand go(BtrPlaceTree parent) {

        if (getChild(0).getType() == ANTLRBtrplaceSL2Parser.VARIABLE) {
            String lbl = getChild(0).getText();
            if (symbols.isImmutable(lbl)) {
                return ignoreError(lbl + " is an immutable variable. Assignment not permitted");
            }
            BtrpOperand e = getChild(0).go(parent);
            BtrpOperand r = getChild(1).go(this);
            BtrpOperand res;
            try {
            switch (type) {
                case PLUS_EQUALS:
                    res = e.plus(r);
                    break;
                case MINUS_EQUALS:
                    res = e.minus(r);
                    break;
                case TIMES_EQUALS:
                    res = e.times(r);
                    break;
                case DIV_EQUALS:
                    res = e.div(r);
                    break;
                case REMAINDER_EQUALS:
                    res = e.remainder(r);
                    break;
                default:
                    return ignoreError("Unsupported operation: " + type);
            }
            } catch (ArithmeticException ex) {
                return ignoreError(ex);
            }
            symbols.declare(lbl, res);
            res.setLabel(lbl);
            return IgnorableOperand.getInstance();
        }
        return ignoreError(getChild(0).getText() + " is not a variable");
    }
}