Introduce refactored wiki parser and renderer

This is a half-way through a big refactoring of the parsing and
rendering infrastructure. The main change is to separate the parse and
render trees, which makes the code a lot cleaner. The new parser isn't
yet functional enough to replace the existing parser so for the moment
you have to manually invoke it with `$tw.testNewParser()` in your
browser console. I really ought to use branches for this kind of
thing...

core/modules/widgets/button.js

@@ -0,0 +1,145 @@
+/*\
+title: $:/core/modules/widget/button.js
+type: application/javascript
+module-type: widget
+
+Implements the button widget.
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var ButtonWidget = function(renderer) {
+	// Save state
+	this.renderer = renderer;
+	// Generate child nodes
+	this.generateChildNodes();
+};
+
+ButtonWidget.prototype.generateChildNodes = function() {
+	// Get the parameters from the attributes
+	this.message = this.renderer.getAttribute("message");
+	this.param = this.renderer.getAttribute("param");
+	this.set = this.renderer.getAttribute("set");
+	this.setTo = this.renderer.getAttribute("setTo");
+	this.popup = this.renderer.getAttribute("popup");
+	this.hover = this.renderer.getAttribute("hover");
+	this.qualifyTiddlerTitles = this.renderer.getAttribute("qualifyTiddlerTitles");
+	this["class"] = this.renderer.getAttribute("class");
+	// Compose the button
+	var classes = ["tw-tiddlybutton"];
+	if(this.classes) {
+		$tw.utils.pushTop(classes,this.classes);
+	}
+	if(this["class"]) {
+		$tw.utils.pushTop(classes,this["class"]);
+	}
+	var events = [{name: "click", handlerObject: this, handlerMethod: "handleClickEvent"}];
+	if(this.hover === "yes") {
+		events.push({name: "mouseover", handlerObject: this, handlerMethod: "handleMouseOverOrOutEvent"});
+		events.push({name: "mouseout", handlerObject: this, handlerMethod: "handleMouseOverOrOutEvent"});
+	}
+	this.children = this.renderer.renderTree.createRenderers(this.renderer.renderContext,[{
+		type: "element",
+		tag: "button",
+		attributes: {
+			"class": {type: "string", value: classes.join(" ")}
+		},
+		children: this.renderer.parseTreeNode.children,
+		events: events
+	}]);
+};
+
+ButtonWidget.prototype.render = function(type) {
+	var output = [];
+	$tw.utils.each(this.children,function(node) {
+		if(node.render) {
+			output.push(node.render(type));
+		}
+	});
+	return output.join("");
+};
+
+ButtonWidget.prototype.renderInDom = function(parentElement) {
+	this.parentElement = parentElement;
+	// Render any child nodes
+	$tw.utils.each(this.children,function(node) {
+		if(node.renderInDom) {
+			parentElement.appendChild(node.renderInDom());
+		}
+	});
+};
+
+ButtonWidget.prototype.dispatchMessage = function(event) {
+	$tw.utils.dispatchCustomEvent(event.target,this.message,{
+		param: this.param,
+		tiddlerTitle: this.renderer.getContextTiddlerTitle()
+	});
+};
+
+ButtonWidget.prototype.triggerPopup = function(event) {
+	$tw.popup.triggerPopup({
+		textRef: this.popup,
+		domNode: this.renderer.domNode,
+		qualifyTiddlerTitles: this.qualifyTiddlerTitles,
+		renderContext: this.renderer.renderContext,
+		wiki: this.renderer.renderTree.wiki
+	});
+};
+
+ButtonWidget.prototype.setTiddler = function() {
+	var tiddler = this.renderer.renderTree.wiki.getTiddler(this.set);
+	this.renderer.renderTree.wiki.addTiddler(new $tw.Tiddler(tiddler,{title: this.set, text: this.setTo}));
+};
+
+ButtonWidget.prototype.handleClickEvent = function(event) {
+	if(this.message) {
+		this.dispatchMessage(event);
+	}
+	if(this.popup) {
+		this.triggerPopup(event);
+	}
+	if(this.set && this.setTo) {
+		this.setTiddler();
+	}
+	event.preventDefault();
+	return false;
+};
+
+ButtonWidget.prototype.handleMouseOverOrOutEvent = function(event) {
+	if(this.popup) {
+		this.triggerPopup(event);
+	}
+	event.preventDefault();
+	return false;
+};
+
+ButtonWidget.prototype.refreshInDom = function(changedAttributes,changedTiddlers) {
+	// Check if any of our attributes have changed, or if a tiddler we're interested in has changed
+ 	if(changedAttributes.message || changedAttributes.param || changedAttributes.set || changedAttributes.setTo || changedAttributes.popup || changedAttributes.hover || changedAttributes.qualifyTiddlerTitles || changedAttributes["class"] || (this.set && changedTiddlers[this.set]) || (this.popup && changedTiddlers[this.popup])) {
+		// Remove old child nodes
+		$tw.utils.removeChildren(this.parentElement);
+		// Regenerate and render children
+		this.generateChildNodes();
+		var self = this;
+		$tw.utils.each(this.children,function(node) {
+			if(node.renderInDom) {
+				self.parentElement.appendChild(node.renderInDom());
+			}
+		});
+	} else {
+		// We don't need to refresh ourselves, so just refresh any child nodes
+		$tw.utils.each(this.children,function(node) {
+			if(node.refreshInDom) {
+				node.refreshInDom(changedTiddlers);
+			}
+		});
+	}
+};
+
+exports.button = ButtonWidget;
+
+})();