minij.parse.Parser.java Source code

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Here is the source code for minij.parse.Parser.java

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/*
 * MiniJCompiler: Compiler for a subset of the Java(R) language
 *
 * (C) Copyright 2014-2015 Tibor Goldschwendt <goldschwendt@cip.ifi.lmu.de>,
 * Michael Seifert <mseifert@error-reports.org>
 *
 * This file is part of MiniJCompiler.
 *
 * MiniJCompiler is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MiniJCompiler 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MiniJCompiler.  If not, see <http://www.gnu.org/licenses/>.
 */
package minij.parse;

import java.io.IOException;
import java.util.BitSet;

import minij.Configuration;
import minij.Logger;
import minij.MiniJLexer;
import minij.MiniJParser;
import minij.parse.rules.Program;
import minij.parse.visitors.ASTVisitor;
import minij.parse.visitors.PrettyPrintVisitor;

import org.antlr.v4.runtime.ANTLRErrorListener;
import org.antlr.v4.runtime.ANTLRFileStream;
import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.RecognitionException;
import org.antlr.v4.runtime.Recognizer;
import org.antlr.v4.runtime.TokenStream;
import org.antlr.v4.runtime.atn.ATNConfigSet;
import org.antlr.v4.runtime.dfa.DFA;
import org.antlr.v4.runtime.tree.ParseTree;

public class Parser {

    private static class ParserErrorListener implements ANTLRErrorListener {

        private boolean errorOccurred = false;

        @Override
        public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol, int line,
                int charPositionInLine, String msg, RecognitionException e) {
            errorOccurred = true;
        }

        @Override
        public void reportAmbiguity(org.antlr.v4.runtime.Parser recognizer, DFA dfa, int startIndex, int stopIndex,
                boolean exact, BitSet ambigAlts, ATNConfigSet configs) {
            errorOccurred = true;
        }

        @Override
        public void reportAttemptingFullContext(org.antlr.v4.runtime.Parser recognizer, DFA dfa, int startIndex,
                int stopIndex, BitSet conflictingAlts, ATNConfigSet configs) {
            errorOccurred = true;
        }

        @Override
        public void reportContextSensitivity(org.antlr.v4.runtime.Parser recognizer, DFA dfa, int startIndex,
                int stopIndex, int prediction, ATNConfigSet configs) {
            errorOccurred = true;
        }

        public boolean didErrorOccurr() {
            return errorOccurred;
        }

    }

    public static Program parse(Configuration config) throws ParserException {
        try {
            ANTLRFileStream reader = new ANTLRFileStream(config.inputFile);
            MiniJLexer lexer = new MiniJLexer((CharStream) reader);
            TokenStream tokens = new CommonTokenStream(lexer);

            MiniJParser parser = new MiniJParser(tokens);
            ParserErrorListener listener = new ParserErrorListener();
            parser.addErrorListener(listener);
            ParseTree parseTree = parser.prog();
            if (listener.didErrorOccurr()) {
                throw new ParserException("Could not parse file");
            }

            ASTVisitor astVisitor = new ASTVisitor();
            Program program = (Program) astVisitor.visit(parseTree);

            Logger.logVerbosely("Successfully parsed input file");

            if (config.printSourceCode) {
                Logger.log(program.accept(new PrettyPrintVisitor("")));
            }

            return program;
        } catch (IOException e) {
            throw new ParserException("Antlr could not open file " + config.inputFile, e);
        } catch (ParserException e) {
            throw e;
        } catch (Exception e) {
            throw new ParserException("Could not parse file", e);
        }
    }
}