InputUtil.jack

class InputUtil {
	static int Ir,Ic;

	function void init() {
		let Ir = 1;
		let Ic = 1;
		return;
	}

	function void eraseMessage() {
		var String s;
		do Output.moveCursor(Ir,Ic);
		let s = "                                                 ";
		do Output.printString(s);
		do s.dispose();
		return;
	}

	function void showMessage(String s) {
		do InputUtil.eraseMessage();
		do Output.moveCursor(Ir,Ic);
		do Output.printString(s);
		do s.dispose();
		return;
	}
	
	// reads only valid inputs!
	// returns 0 for quit and 1 to 9 for moves!
	function int readInput(String s) {
		var char c;
		var int choice;
		do InputUtil.eraseMessage();		
		while(true) {
			do Output.moveCursor(Ir,Ic);
			do Output.printString(s);
			let c = Keyboard.readChar();
			// 48 to 57
			if((c>47) & (c<58)) {
				do s.dispose();
				return c-48;
			}
		}
		return 0;// Never reach here!
	}
	
	function int waitForZeroOrOne(String s) {
		var char c;
		var int choice;
		do InputUtil.eraseMessage();		
		while(true) {
			do Output.moveCursor(Ir,Ic);
			do Output.printString(s);
			let c = Keyboard.readChar();
			// 48 to 57
			if((c>47) & (c<50)) {
				do s.dispose();
				return c-48;
			}
		}
		return 0;// Never reach here!
	}
}