/*
 * Name: Mike Cifelli
 * Course: CIS 443 - Programming Languages
 * Assignment: Lisp Parser
 */

package main;

import parser.*;
import error.ErrorManager;
import java.io.*;

/**
 * <code>LispParserDriver</code> is a program that takes the name of a file
 * as a command-line argument, creates an internal representation of the
 * S-expressions found in the file and prints them to the console. If no file
 * name is provided at the command-line, this program will read from standard
 * input.
 */
public class LispParserDriver {

    /**
     * Create internal representations of the S-expressions found in the file
     * whose name was given as a command-line argument and print them to the
     * console. If no file name was given, retrieve the S-expressions from
     * standard input.
     *
     * @param args
     *  the command-line arguments:
     *  <ul>
     *      <li><code>args[0]</code> - file name (optional)</li>
     *  </ul>
     */
    public static void main(String[] args) {
        LispParser parser = null;

        if (args.length > 0) {
            // a file name was given at the command-line, attempt to create a
            // 'LispParser' on it
            try {
                parser = new LispParser(new FileInputStream(args[0]), args[0]);
            } catch (FileNotFoundException e) {
                ErrorManager.generateError(e.getMessage(),
                                           ErrorManager.CRITICAL_LEVEL);
            }
        } else {
            // no file name was given, create a 'LispParser' on standard input
            parser = new LispParser(System.in, "System.in");
        }

        while (! parser.eof()) {
            try {
                SExpression sexpr = parser.getSExpr();

                System.out.println(sexpr.toString());
            } catch (RuntimeException e) {
                ErrorManager.generateError(e.getMessage(), 2);
            } catch (IOException e) {
                ErrorManager.generateError(e.getMessage(),
                                           ErrorManager.CRITICAL_LEVEL);
            }
        }
    }

}