KahluaInterpreter.java

/*
 Copyright (c) 2009 Kristofer Karlsson <kristofer.karlsson@gmail.com>

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 */
import java.io.IOException;
import java.io.PrintStream;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import se.krka.kahlua.luaj.compiler.LuaCompiler;
import se.krka.kahlua.vm.LuaClosure;
import se.krka.kahlua.vm.LuaState;


public class KahluaInterpreter extends MIDlet implements CommandListener, Runnable {
	private TextField input;
	private Command run;
	private Command exit;
	private Form form;
	private LuaState state;
	private Command clear;
	private boolean alive = true;

	private Object notifyObject = new Object();
	private String source;

	public KahluaInterpreter() {
		run = new Command("Run", Command.OK, 1);
		clear = new Command("Clear", Command.OK, 90);
		exit = new Command("Exit", Command.EXIT, 100);

		form = new Form("Kahlua Interpreter");
		input = new TextField("Input", "", 200, TextField.ANY);

		PrintStream printStream = new PrintStream(System.out) {
			public void println(String s) {
				form.append(s + "\n");
			}
		};
		state = new LuaState(printStream);
		LuaCompiler.register(state);

		form.setCommandListener(this);
		form.addCommand(exit);
		form.addCommand(run);
		form.addCommand(clear);

		form.append(input);

		new Thread(this).start();

		Display.getDisplay(this).setCurrent(form);
	}

	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		alive = false;
		synchronized (notifyObject) {
			notifyObject.notifyAll();
		}
	}

	protected void pauseApp() {
	}
	protected void startApp() throws MIDletStateChangeException {
	}

	public void commandAction(Command command, Displayable display) {
		if (command == exit) {
			notifyDestroyed();
			return;
		}
		if (command == run) {
			form.removeCommand(run);
			clearOutput();
			source = input.getString();
			if (source.startsWith("=")) {
				source = "return " + source.substring(1);
			}
			synchronized (notifyObject) {
				notifyObject.notifyAll();
			}
			return;
		}

		if (command == clear) {
			input.setString("");
			return;
		}
	}

	private void clearOutput() {
		for (int i = form.size() - 1; i >= 1; i--) {
			form.delete(i);
		}
	}

	public void run() {
		while (alive) {
			synchronized (notifyObject) {
				try {
					notifyObject.wait();
				} catch (InterruptedException e) {
					
				}
			}
			if (source != null) {
				try {
					state.out.println("Compiling...");
					LuaClosure closure = LuaCompiler.loadstring(source, "stdin", state.getEnvironment());
					source = null;
					clearOutput();
					state.out.println("Running...");
					Object[] result = state.pcall(closure);

					if (result != null) {
						if (result[0] == Boolean.TRUE) {
							StringBuffer line = new StringBuffer();
							for (int i = 1; i < result.length; i++) {
								if (i > 1) {
									line.append(", ");
								}
								line.append(result[i].toString());
							}
							state.out.println(line.toString());
						} else {
							if (result[1] instanceof String) {
								state.out.println((String) result[1]);
							}
							if (result[2] instanceof String) {
								state.out.println((String) result[2]);
							}
						}
					}
				} catch (RuntimeException e) {
					state.out.println(e.getMessage());
				} catch (IOException e) {
					state.out.println(e.getMessage());
				}
				// delete the "running..." text
				form.delete(1);
				form.addCommand(run);
			}
		}
	}
}