com.jmcalc.ExpressionParser.java Source code

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Here is the source code for com.jmcalc.ExpressionParser.java

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/*
 *  Copyright 2012-2013 Marcelo Portilho
 *
 *  Licensed 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.jmcalc;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.BailErrorStrategy;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.DefaultErrorStrategy;

import com.jmcalc.grammar.JMCalcLexer;
import com.jmcalc.grammar.JMCalcParser;
import com.jmcalc.utils.DescriptiveErrorListener;

public abstract class ExpressionParser {

    protected static JMCalcParser produceParse(String expression) {
        JMCalcLexer lexer = new JMCalcLexer(new ANTLRInputStream(expression));
        lexer.removeErrorListeners();
        lexer.addErrorListener(DescriptiveErrorListener.INSTANCE);
        JMCalcParser parser = new JMCalcParser(new CommonTokenStream(lexer));
        parser.setErrorHandler(new BailErrorStrategy());
        parser.removeErrorListeners();
        parser.addErrorListener(DescriptiveErrorListener.INSTANCE);
        return parser;
    }

    protected static JMCalcParser setDefaultErrorMode(JMCalcParser parser) {
        parser.setErrorHandler(new DefaultErrorStrategy());
        return parser;
    }

}