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;

public class LispMain {

    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";
    private PipedInputStream inputReader;
    private PipedOutputStream inputWriter;
    private PipedInputStream outputReader;
    private PipedOutputStream outputWriter;
    private LispTerminal lispTerminal;

    private LispMain() throws IOException {
        inputReader = new PipedInputStream();
        inputWriter = new PipedOutputStream(inputReader);
        outputReader = new PipedInputStream();
        outputWriter = new PipedOutputStream(outputReader);
        lispTerminal = new LispTerminal(createIOSafeTerminal(), inputWriter, outputReader);
    }

    private IOSafeTerminal createIOSafeTerminal() throws IOException {
        return IOSafeTerminalAdapter.createRuntimeExceptionConvertingAdapter(new DefaultTerminalFactory().createTerminal());
    }

    public static void main(String[] args) throws IOException {
        new LispMain().run(args);
    }

    private void run(String[] args) {
        if (args.length == 0)
            lispTerminal.run();

        LispInterpreter interpreter = buildInterpreter(args);
        interpreter.interpret();
    }

    private LispInterpreter buildInterpreter(String[] args) {
        LispInterpreterBuilder builder = LispInterpreterBuilderImpl.getInstance();
        configureInput(args, builder);
        configureOutput(args, builder);
        configureTerminatingFunctions(args, builder);
        configureDecorators(args, builder);

        return builder.build();
    }

    private void configureTerminatingFunctions(String[] args, LispInterpreterBuilder builder) {
        if (args.length > 0) {
            builder.setTerminationFunction(() -> System.exit(0));
            builder.setErrorTerminationFunction(() -> System.exit(1));
        } else {
            builder.setTerminationFunction(this::shutdown);
            builder.setErrorTerminationFunction(this::shutdown);
        }
    }

    private void configureDecorators(String[] args, LispInterpreterBuilder builder) {
        if (args.length > 0) {
            builder.setOutputDecorator(makeColorDecorator(ANSI_GREEN));
            builder.setValueOutputDecorator(makeColorDecorator(ANSI_GREEN));
            builder.setWarningOutputDecorator(makeColorDecorator(ANSI_YELLOW));
            builder.setErrorOutputDecorator(makeColorDecorator(ANSI_RED));
            builder.setCriticalOutputDecorator(makeColorDecorator(ANSI_PURPLE));
        } else {
            builder.setOutputDecorator(makeInteractiveDecorator(ANSI_GREEN));
            builder.setValueOutputDecorator(s -> s);
            builder.setWarningOutputDecorator(s -> s);
            builder.setErrorOutputDecorator(s -> s);
            builder.setCriticalOutputDecorator(s -> s);
        }
    }

    private void shutdown() {
        try {
            lispTerminal.finish();
            outputWriter.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private void configureOutput(String[] args, LispInterpreterBuilder builder) {
        if (args.length > 0) {
            builder.setOutput(System.out);
            builder.setErrorOutput(System.err);
        } else {
            PrintStream outputStream = new PrintStream(outputWriter);
            builder.setOutput(outputStream);
            builder.setErrorOutput(outputStream);
        }
    }

    private void configureInput(String[] args, LispInterpreterBuilder builder) {
        if (args.length > 0)
            builder.useFile(args[0]);
        else
            builder.setInput(inputReader, "stdin");
    }

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

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

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

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

}