UnidadesMain.java

import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.*;
import org.stringtemplate.v4.*;
import java.io.File;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.io.FileInputStream;

public class UnidadesMain {
    public static void main(String[] args) throws Exception {
        try 
        {
            // create a CharStream that reads from standard input:
            CharStream input = CharStreams.fromStream(new FileInputStream(args[0]));
            // create a lexer that feeds off of input CharStream:
            UnidadesLexer lexer = new UnidadesLexer(input);
            // create a buffer of tokens pulled from the lexer:
            CommonTokenStream tokens = new CommonTokenStream(lexer);
            // create a parser that feeds off the tokens buffer:
            UnidadesParser parser = new UnidadesParser(tokens);
            // replace error listener:
            //parser.removeErrorListeners(); // remove ConsoleErrorListener
            //parser.addErrorListener(new ErrorHandlingListener());
            // begin parsing at main rule:
            ParseTree tree = parser.main();
            if (parser.getNumberOfSyntaxErrors() == 0) {
                // print LISP-style tree:
                // System.out.println(tree.toStringTree(parser));
                kOSUnitVisitor2 vis = new kOSUnitVisitor2();
                UnidadesSemanticCheck semanticCheck = new UnidadesSemanticCheck();
                semanticCheck.visit(tree);
                if (!ErrorHandling.error()) {
                    ST code = vis.visit(tree);
                    String filename = "Units.py";
                    try 
                    {
                        PrintWriter pw = new PrintWriter(new File(filename));
                        pw.print(code.render());
                        pw.close();
                    } 
                    catch (IOException e) 
                    {
                        ErrorHandling.printError("Unable to write in file " + filename);
                        System.exit(3);
                    }
                }
            }
        }
        catch (FileNotFoundException e) 
        {
            ErrorHandling.printError("Could not open input file \"" + args[0] + "\" – ending program...");
            System.exit(1);
        }
    }
}