Split "transclude" widget into a separate "tiddler" and "transclude" widget

Belatedly realised that the design would be clearer without these two
separate concepts being conflated into a single widget.

As a result of this change, any other widget or template that generates
transclude widgets has needed adjustment.

core/modules/widgets/tiddler.js

@@ -0,0 +1,82 @@
+/*\
+title: $:/core/modules/widgets/tiddler.js
+type: application/javascript
+module-type: widget
+
+The tiddler widget sets the current tiddler to a specified title.
+
+Attributes:
+	title: the title of the current tiddler
+	class: CSS classes
+
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var TiddlerWidget = function(renderer) {
+	// Save state
+	this.renderer = renderer;
+	// Generate child nodes
+	this.generate();
+};
+
+TiddlerWidget.prototype.generate = function() {
+	var self = this;
+	this.tiddlerTitle = this.renderer.getAttribute("title","");
+	// Set up the attributes for the wrapper element
+	var classes = ["tw-tiddler"];
+	if(this.renderer.hasAttribute("class")) {
+		$tw.utils.pushTop(classes,this.renderer.getAttribute("class").split(" "));
+	}
+	if(!this.renderer.renderTree.wiki.tiddlerExists(this.tiddlerTitle) && !this.renderer.renderTree.wiki.isShadowTiddler(this.tiddlerTitle)) {
+		$tw.utils.pushTop(classes,"tw-tiddler-missing");
+	}
+	// Save the context for this renderer node
+	this.renderer.context = {
+		tiddlerTitle: this.tiddlerTitle
+	};
+	// Initialise events
+	this.events = [];
+	// Trap and update tag modification events
+	this.events.push({name: "tw-remove-tag", handlerFunction: function(event) {
+		event.currentTag = self.tiddlerTitle;
+		return true;
+	}});
+	// Set the element
+	this.tag = this.renderer.parseTreeNode.isBlock ? "div" : "span";
+	this.attributes = {};
+	if(classes.length > 0) {
+		this.attributes["class"] = classes.join(" ");
+	}
+	this.children = this.renderer.renderTree.createRenderers(this.renderer,this.renderer.parseTreeNode.children);
+};
+
+TiddlerWidget.prototype.refreshInDom = function(changedAttributes,changedTiddlers) {
+	// Set the class for missing tiddlers
+	if(this.tiddlerTitle && changedTiddlers[this.tiddlerTitle]) {
+		$tw.utils.toggleClass(this.renderer.domNode,"tw-tiddler-missing",!this.renderer.renderTree.wiki.tiddlerExists(this.tiddlerTitle));
+	}
+	// Check if any of our attributes have changed, or if a tiddler we're interested in has changed
+	if(changedAttributes.title) {
+		// Regenerate and rerender the widget and replace the existing DOM node
+		this.generate();
+		var oldDomNode = this.renderer.domNode,
+			newDomNode = this.renderer.renderInDom();
+		oldDomNode.parentNode.replaceChild(newDomNode,oldDomNode);
+	} 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.tiddler = TiddlerWidget;
+
+})();