transcendental-lisp/src/main/LispMain.java

package main;

import java.io.*;

import error.*;
import interpreter.*;

public class LispMain {

    private LispMain() {}

    public static void main(String[] args) {
        LispInterpreter interpreter = null;
        ErrorManager errorManager = new ErrorManager(new TerminateInterpreter(), System.err::print);

        if (args.length > 0) {
            String fileName = args[0];

            try {
                interpreter = new LispInterpreter(new FileInputStream(fileName), errorManager, System.out);
            } catch (FileNotFoundException e) {
                errorManager.generateError(new LispFileNotFoundException(e));
            }
        } else
            interpreter = new InteractiveLispInterpreter(System.in, errorManager, System.out);

        interpreter.interpret();
    }

    private static class TerminateInterpreter implements Runnable {

        @Override
        public void run() {
            System.exit(1);
        }
    }

    public static class LispFileNotFoundException extends LispException {

        private static final long serialVersionUID = 1L;
        private String message;

        public LispFileNotFoundException(FileNotFoundException e) {
            this.message = e.getMessage();
        }

        @Override
        public int getSeverity() {
            return ErrorManager.CRITICAL_LEVEL;
        }

        @Override
        public String getMessage() {
            return message;
        }
    }

}