transcendental-lisp/src/main/LispMain.java

package main;

import static terminal.LispTerminal.END_OF_SEGMENT;

import java.io.*;
import java.util.function.Function;

import com.googlecode.lanterna.terminal.*;

import interpreter.*;
import terminal.LispTerminal;
import terminal.SafeStream.SafeOutputStream;
import terminal.SafeStream.UncheckedIOException;

public class LispMain {

    private static final String GREETING = "Transcendental Lisp - Version 1.0.1";
    private static final String ANSI_RESET = "\u001B[0m";
    private static final String ANSI_RED = "\u001B[31m";
    private static final String ANSI_GREEN = "\u001B[32m";
    private static final String ANSI_YELLOW = "\u001B[33m";
    private static final String ANSI_PURPLE = "\u001B[35m";

    public static void main(String[] args) throws IOException {
        LispMain lispMain = new LispMain();

        if (args.length == 0)
            lispMain.runInteractive();
        else
            lispMain.runWithFile(args[0]);
    }

    private PipedInputStream inputReader;
    private PipedOutputStream inputWriter;
    private PipedInputStream outputReader;
    private PipedOutputStream outputWriter;
    private PrintStream outputStream;
    private SafeOutputStream safeOutputWriter;
    private LispTerminal lispTerminal;

    private void runInteractive() {
        initializeTerminalAndStreams();
        printGreeting();
        lispTerminal.start();
        buildInteractiveInterpreter().interpret();
        outputStream.close();
    }

    private void initializeTerminalAndStreams() {
        try {
            initalizeTerminalAndStreamsWithException();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    private void initalizeTerminalAndStreamsWithException() throws IOException {
        inputReader = new PipedInputStream();
        inputWriter = new PipedOutputStream(inputReader);
        outputReader = new PipedInputStream();
        outputWriter = new PipedOutputStream(outputReader);
        outputStream = new PrintStream(outputWriter);
        safeOutputWriter = new SafeOutputStream(outputWriter);
        lispTerminal = new LispTerminal(createIOSafeTerminal(), inputWriter, outputReader);
    }

    private IOSafeTerminal createIOSafeTerminal() throws IOException {
        Terminal defaultTerminal = new DefaultTerminalFactory().createTerminal();

        return IOSafeTerminalAdapter.createRuntimeExceptionConvertingAdapter(defaultTerminal);
    }

    private void printGreeting() {
        outputStream.println(GREETING);
        outputStream.println();
    }

    private LispInterpreter buildInteractiveInterpreter() {
        LispInterpreterBuilder builder = LispInterpreterBuilderImpl.getInstance();
        builder.setInput(inputReader, "terminal");
        builder.setOutput(outputStream);
        builder.setErrorOutput(outputStream);
        builder.setTerminationFunction(this::shutdown);
        builder.setErrorTerminationFunction(this::shutdown);
        builder.setPromptDecorator(s -> s + END_OF_SEGMENT);
        builder.setValueOutputDecorator(makeColorDecorator(ANSI_GREEN));
        builder.setWarningOutputDecorator(makeColorDecorator(ANSI_YELLOW));
        builder.setErrorOutputDecorator(makeColorDecorator(ANSI_RED));
        builder.setCriticalOutputDecorator(makeColorDecorator(ANSI_PURPLE));

        return builder.build();
    }

    private void shutdown() {
        outputStream.println();
        outputStream.println(END_OF_SEGMENT);
        lispTerminal.stop();
        safeOutputWriter.close();
    }

    private void runWithFile(String fileName) {
        buildFileInterpreter(fileName).interpret();
    }

    private LispInterpreter buildFileInterpreter(String fileName) {
        LispInterpreterBuilder builder = LispInterpreterBuilderImpl.getInstance();
        builder.useFile(fileName);
        builder.setOutput(System.out);
        builder.setErrorOutput(System.err);
        builder.setTerminationFunction(() -> System.exit(0));
        builder.setErrorTerminationFunction(() -> System.exit(1));
        builder.setValueOutputDecorator(makeColorDecorator(ANSI_GREEN));
        builder.setWarningOutputDecorator(makeColorDecorator(ANSI_YELLOW));
        builder.setErrorOutputDecorator(makeColorDecorator(ANSI_RED));
        builder.setCriticalOutputDecorator(makeColorDecorator(ANSI_PURPLE));

        return builder.build();
    }

    private static Function<String, String> makeColorDecorator(String color) {
        return new Function<String, String>() {

            @Override
            public String apply(String s) {
                return color + s + ANSI_RESET;
            }
        };
    }

}