[Xswt-developer] Javascript support

[<ha...@id...>]

Hi,

As some of you may recall, I have been working on scripting support i.e.
<script> tags, e.g. to be able to handle events. The first language I
managed to get working was pnuts, which was the one I knew best
(technically). However, I've now been able to get GNUs JavaScript engine
Rhino working, too. Since JavaScript is something a lot of people =
already
know and Rhino I believe is bundled with with Java 6 (?), this should be
good for XSWT. Below is a calculator example; the script tags implement =
the
calculator logic and the selectionListener attributes calls the =
functions
defined in the script tags. Note how all the widgets (with ids) are
accessible to the script. There's still some small things to do before
checking it in, but I thought I'd mention it.=20

Hallvard

<?xml version=3D"1.0" encoding=3D"UTF-8"?>
<xswt xmlns:x=3D"http://sweet_swt.sf.net/xswt">
   <x:import>
       <package name=3D"java.lang"/>
       <package name=3D"org.eclipse.swt.widgets"/>
       <package name=3D"com.swtworkbench.community.xswt.scripting"/>
       <package name=3D"org.eclipse.swt.layout"/>
   </x:import>
   <composite>
       <layout x:class=3D"gridLayout" numColumns=3D"5"/>
       <script x:id=3D"math" lang=3D"js">
        	function plus (n1, n2) { return (+n1) + (+n2);}
    		function minus(n1, n2) { return n1 - n2;}
    		function mult (n1, n2) { return n1 * n2;}
    		function div  (n1, n2) { return n1 / n2;}
    	</script>
       <text x:id=3D"result">
       		<layoutData x:class=3D"gridData" horizontalSpan=3D"5"
horizontalAlignment=3D"FILL" grabExcessHorizontalSpace=3D"true"/>
       </text>
       <result text=3D"                    0"/>
       <script x:id=3D"calc" lang=3D"js">
       		var n1 =3D 0;
       		var n2 =3D null;
       		var mem =3D 0;
       		var op =3D null;
       		function setOp(sop) {
       			setN1(getN(n1));
       			if (sop =3D=3D "-") {
       				op =3D math.minus;
       			} else if (sop =3D=3D "+") {
       				op =3D math.plus;
       			} else if (sop =3D=3D "*") {
       				op =3D math.mult;
       			} else if (sop =3D=3D "/") {
       				op =3D math.div;
       			} else {
       				op =3D sop;
       			}
       			n2 =3D "";
       		}
       		function getN(n) {
       			return (+n);
       		}
       		function updateDigits() {
       			var digits =3D (typeof(n2) =3D=3D "string") ? n2 : n1;
				result.text =3D digits;
       		}
       		function appendDigit(d) {
       			if (typeof(n2) =3D=3D "string") {
       				n2 =3D n2 + d;
       			} else if (typeof(n1) =3D=3D "string") {
       				n1 =3D n1 + d;
       			} else {
       				n1 =3D d;
       			}
       			updateDigits();
       		}
       		function setN1(n) {
       			n1 =3D n;
       			n2 =3D null;
	       		op =3D null;
	       		return n;
       		}
       		function setN2(n) {
       			n2 =3D n;
       			return n;
       		}
       		function calculate() {
       			if (op !=3D null) {
       				setN2(getN(n2));
       				setN1(op(n1,n2));
	       		}
		       	updateDigits();
       		}
       		function setMem(n) {
       			mem =3D n;
       		}
    	</script>
       <button text=3D"MC" selectionListener=3D"handlers.memClear"/>
       <button text=3D"7" selectionListener=3D"handlers.digit"/>
       <button text=3D"8" selectionListener=3D"handlers.digit"/>
       <button text=3D"9" selectionListener=3D"handlers.digit"/>
       <button text=3D"/" selectionListener=3D"handlers.op"/>

       <button text=3D"MR" selectionListener=3D"handlers.memRecall"/>
       <button text=3D"4" selectionListener=3D"handlers.digit"/>
       <button text=3D"5" selectionListener=3D"handlers.digit"/>
       <button text=3D"6" selectionListener=3D"handlers.digit"/>
       <button text=3D"*" selectionListener=3D"handlers.op"/>

       <button text=3D"M+" selectionListener=3D"handlers.memPlus"/>
       <button text=3D"1" selectionListener=3D"handlers.digit"/>
       <button text=3D"2" selectionListener=3D"handlers.digit"/>
       <button text=3D"3" selectionListener=3D"handlers.digit"/>
       <button text=3D"-" selectionListener=3D"handlers.op"/>

       <button text=3D"C" selectionListener=3D"handlers.clear"/>
       <button text=3D"0" selectionListener=3D"handlers.digit"/>
       <button text=3D","/>
       <button text=3D"=3D" selectionListener=3D"handlers.calculate"/>
       <button text=3D"+" selectionListener=3D"handlers.op"/>
      =20
       <script x:id=3D"handlers" lang=3D"js">
       		function digit(event) {
       			calc.appendDigit("" + event.widget.text); // force
conversion to JavaScript string
       		}
       		function op(event) {
       			calc.setOp("" + event.widget.text); // force
conversion to JavaScript string
       		}
       		function clear(event) {
       			calc.setN1(0);
       			calc.updateDigits();
       		}
       		function memClear(event) {
       			calc.setMem(0);
       		}
       		function memRecall(event) {
       			calc.setN1(mem);
       		}
       		function memPlus(event) {
       			calc.setMem(mem + calc.setN1());
       		}
       		function calculate(event) {
       			calc.calculate();
       		}
       </script>
   </composite>
</xswt>

---
Hallvard Tr=E6tteberg (ha...@id..., http://www.idi.ntnu.no/~hal)
Associate Professor, IS group, Dept. of Computer and Information =
Sciences at
the Norwegian Univ. of Science and Technology