TiddlyWiki5/core/modules/widgets/widget.js

/*\
title: $:/core/modules/widgets/widget.js
type: application/javascript
module-type: widget
\*/

"use strict";

var Widget = function(parseTreeNode,options) {
	this.initialise(parseTreeNode,options);
};

Widget.prototype.initialise = function(parseTreeNode,options) {
	// Bail if parseTreeNode is undefined, meaning  that the widget constructor was called without any arguments so that it can be subclassed
	if(parseTreeNode === undefined) {
		return;
	}
	options = options || {};
	// Save widget info
	this.parseTreeNode = parseTreeNode;
	this.wiki = options.wiki;
	this.parentWidget = options.parentWidget;
	this.variables = Object.create(this.parentWidget ? this.parentWidget.variables : null);
	this.document = options.document;
	this.attributes = {};
	this.children = [];
	this.domNodes = [];
	this.eventListeners = {};
	// Hashmap of the widget classes
	if(!this.widgetClasses) {
		// Get widget classes
		Widget.prototype.widgetClasses = $tw.modules.applyMethods("widget");
		// Process any subclasses
		$tw.modules.forEachModuleOfType("widget-subclass",function(title,module) {
			if(module.baseClass) {
				var baseClass = Widget.prototype.widgetClasses[module.baseClass];
				if(!baseClass) {
					throw "Module '" + title + "' is attemping to extend a non-existent base class '" + module.baseClass + "'";
				}
				var subClass = module.constructor;
				subClass.prototype = new baseClass();
				$tw.utils.extend(subClass.prototype,module.prototype);
				Widget.prototype.widgetClasses[module.name || module.baseClass] = subClass;
			}
		});
	}
};

Widget.prototype.render = function(parent,nextSibling) {
	this.parentDomNode = parent;
	this.execute();
	this.renderChildren(parent,nextSibling);
};

Widget.prototype.execute = function() {
	this.makeChildWidgets();
};

Widget.prototype.setVariable = function(name,value,params,isMacroDefinition,options) {
	options = options || {};
	var valueIsArray = $tw.utils.isArray(value);
	this.variables[name] = {
		value: valueIsArray ? (value[0] || "") : value,
		resultList: valueIsArray ? value : [value],
		params: params,
		isMacroDefinition: !!isMacroDefinition,
		isFunctionDefinition: !!options.isFunctionDefinition,
		isProcedureDefinition: !!options.isProcedureDefinition,
		isWidgetDefinition: !!options.isWidgetDefinition,
		configTrimWhiteSpace: !!options.configTrimWhiteSpace
	};
};

Widget.prototype.getVariableInfo = function(name,options) {
	options = options || {};
	var self = this,
		actualParams = options.params || [],
		variable;
	if(options.allowSelfAssigned) {
		variable = this.variables[name];
	} else {
		variable = this.parentWidget && this.parentWidget.variables[name];
	}

	if(variable) {
		var originalValue = variable.value,
			value = originalValue,
			params = [],
			resultList = [value];
		// Only substitute parameter and variable references if this variable was defined with the \define pragma
		if(variable.isMacroDefinition) {
			params = self.resolveVariableParameters(variable.params,actualParams);
			// Substitute any parameters specified in the definition
			$tw.utils.each(params,function(param) {
				if("name" in param) {
					value = $tw.utils.replaceString(value,new RegExp("\\$" + $tw.utils.escapeRegExp(param.name) + "\\$","mg"),param.value);
				}
			});
			value = self.substituteVariableReferences(value,options);
			resultList = [value];
		} else if(variable.isFunctionDefinition) {
			// Function evaluations
			params = self.resolveVariableParameters(variable.params,actualParams);
			var variables = $tw.utils.extend({},options.variables);
			// Apply default parameter values
			$tw.utils.each(variable.params,function(param,index) {
				if(param["default"]) {
					variables[param.name] = param["default"];
				}
			});
			// Parameters are an array of {name:, value:, multivalue:} pairs (name and multivalue are optional)
			$tw.utils.each(params,function(param) {
				if(param.multiValue && param.multiValue.length) {
					variables[param.name] = param.multiValue;
				} else {
					variables[param.name] = param.value || "";
				}
			});
			resultList = this.wiki.filterTiddlers(value,this.makeFakeWidgetWithVariables(variables),options.source);
			value = resultList[0] || "";
		} else {
			if(variable.resultList) {
				resultList = variable.resultList;
			}
			params = variable.params;
		}
		return {
			text: value,
			params: params,
			resultList: resultList,
			srcVariable: variable,
			isCacheable: originalValue === value
		};
	}

	var text = this.evaluateMacroModule(name,actualParams);
	if(text === undefined) {
		text = options.defaultValue;
	}
	return {
		text: text,
		resultList: [text]
	};
};

Widget.prototype.getVariable = function(name,options) {
	return this.getVariableInfo(name,options).text;
};

Widget.prototype.resolveVariableParameters = function(formalParams,actualParams) {
	formalParams = formalParams || [];
	actualParams = actualParams || [];
	var nextAnonParameter = 0, // Next candidate anonymous parameter in macro call
		paramInfo, paramValue, paramMultiValue,
		results = [];
	// Step through each of the parameters in the macro definition
	for(var p=0; p<formalParams.length; p++) {
		// Check if we've got a macro call parameter with the same name
		paramInfo = formalParams[p];
		paramValue = undefined;
		paramMultiValue = undefined;
		for(var m=0; m<actualParams.length; m++) {
			if(typeof actualParams[m] !== "string" && actualParams[m].name === paramInfo.name) {
				paramValue = actualParams[m].value;
				paramMultiValue = actualParams[m].multiValue || [paramValue]
			}
		}
		// If not, use the next available anonymous macro call parameter
		while(nextAnonParameter < actualParams.length && actualParams[nextAnonParameter].name) {
			nextAnonParameter++;
		}
		if(paramValue === undefined && nextAnonParameter < actualParams.length) {
			var param = actualParams[nextAnonParameter++];
			paramValue = typeof param === "string" ? param : param.value;
			paramMultiValue = typeof param === "string" ? [param] : (param.multiValue || [paramValue]);
		}
		// If we've still not got a value, use the default, if any
		if(!paramValue) {
			paramValue = paramInfo["default"] || "";
			paramMultiValue = [paramValue];
		}

		results.push({name: paramInfo.name, value: paramValue, multiValue: paramMultiValue});
	}
	return results;
};

Widget.prototype.substituteVariableReferences = function(text,options) {
	var self = this;
	return (text || "").replace(/\$\(([^\)\$]+)\)\$/g,function(match,p1,offset,string) {
		return options.variables && options.variables[p1] || (self.getVariable(p1,{defaultValue: ""}));
	});
};

Widget.prototype.evaluateMacroModule = function(name,actualParams,defaultValue) {
	if($tw.utils.hop($tw.macros,name)) {
		var macro = $tw.macros[name],
			args = [];
		if(macro.params.length > 0) {
			var nextAnonParameter = 0, // Next candidate anonymous parameter in macro call
				paramInfo, paramValue;
			// Step through each of the parameters in the macro definition
			for(var p=0; p<macro.params.length; p++) {
				// Check if we've got a macro call parameter with the same name
				paramInfo = macro.params[p];
				paramValue = undefined;
				for(var m=0; m<actualParams.length; m++) {
					if(actualParams[m].name === paramInfo.name) {
						paramValue = actualParams[m].value;
					}
				}
				// If not, use the next available anonymous macro call parameter
				while(nextAnonParameter < actualParams.length && actualParams[nextAnonParameter].name) {
					nextAnonParameter++;
				}
				if(paramValue === undefined && nextAnonParameter < actualParams.length) {
					paramValue = actualParams[nextAnonParameter++].value;
				}
				// If we've still not got a value, use the default, if any
				paramValue = paramValue || paramInfo["default"] || "";
				// Save the parameter
				args.push(paramValue);
			}
		}
		else for(var i=0; i<actualParams.length; ++i) {
			args.push(actualParams[i].value);
		}
		return (macro.run.apply(this,args) || "").toString();
	} else {
		return defaultValue;
	}
};

Widget.prototype.hasVariable = function(name,value) {
	var node = this;
	while(node) {
		if($tw.utils.hop(node.variables,name) && node.variables[name].value === value) {
			return true;
		}
		node = node.parentWidget;
	}
	return false;
};

Widget.prototype.getStateQualifier = function(name) {
	this.qualifiers = this.qualifiers || Object.create(null);
	name = name || "transclusion";
	if(this.qualifiers[name]) {
		return this.qualifiers[name];
	} else {
		var output = [],
			node = this;
		while(node && node.parentWidget) {
			if($tw.utils.hop(node.parentWidget.variables,name)) {
				output.push(node.getVariable(name));
			}
			node = node.parentWidget;
		}
		var value = $tw.utils.hashString(output.join(""));
		this.qualifiers[name] = value;
		return value;
	}
};

Widget.prototype.makeFakeWidgetWithVariables = function(vars = {}) {
	const self = this;

	const fakeWidget = {
		getVariableInfo(name,opts = {}) {
			if(name in vars) {
				const value = vars[name];
				return Array.isArray(value)
					? { text: value[0], resultList: value }
					: { text: value, resultList: [value] };
			}
			opts = opts || {};
			opts.variables = Object.assign({}, vars, opts.variables || {});
			return self.getVariableInfo(name, opts);
		},

		getVariable(name,opts) {
			return this.getVariableInfo(name, opts).text;
		},

		resolveVariableParameters: self.resolveVariableParameters,
		wiki: self.wiki,
		makeFakeWidgetWithVariables: self.makeFakeWidgetWithVariables,

		get variables() {
			// Merge parent vars via prototype-like delegation
			return Object.create(self.variables || {},
				Object.keys(vars).reduce((acc, key) => {
					acc[key] = { value: vars[key], enumerable: true, configurable: true };
					return acc;
				}, {})
			);
		}
	};

	return fakeWidget;
};

Widget.prototype.computeAttributes = function(options) {
	options = options || {};
	var changedAttributes = {},
		self = this,
		newMultiValuedAttributes = Object.create(null);
	$tw.utils.each(this.parseTreeNode.attributes,function(attribute,name) {
		if(options.filterFn) {
			if(!options.filterFn(name)) {
				return;
			}
		}
		var value = self.computeAttribute(attribute,options),
			multiValue = null;
		if($tw.utils.isArray(value)) {
			multiValue = value;
			newMultiValuedAttributes[name] = multiValue;
			value = value[0] || "";
		}
		var changed = (self.attributes[name] !== value);
		if(!changed && multiValue && self.multiValuedAttributes) {
			changed = !$tw.utils.isArrayEqual(self.multiValuedAttributes[name] || [], multiValue);
		}
		if(changed) {
			self.attributes[name] = value;
			changedAttributes[name] = true;
		}
	});
	this.multiValuedAttributes = newMultiValuedAttributes;
	return changedAttributes;
};

Widget.prototype.computeAttribute = function(attribute,options) {
	options = options || {};
	var self = this,
		value;
	if(attribute.type === "filtered") {
		value = this.wiki.filterTiddlers(attribute.filter,this);
		if(!options.asList) {
			value = value[0] || "";
		}
	} else if(attribute.type === "indirect") {
		value = this.wiki.getTextReference(attribute.textReference,"",this.getVariable("currentTiddler"));
		if(value && options.asList) {
			value = [value];
		}
	} else if(attribute.type === "macro") {
		// Get the macro name
		var macroName = attribute.value.attributes["$variable"].value;
		// Collect macro parameters
		var params = [];
		$tw.utils.each(attribute.value.orderedAttributes,function(attr) {
			var param = {
				value: self.computeAttribute(attr)
			};
			if(attr.name && !attr.isPositional) {
				param.name = attr.name;
			}
			params.push(param);
		});
		// Invoke the macro
		var variableInfo = this.getVariableInfo(macroName,{params: params});
		if(options.asList || attribute.isMVV) {
			value = variableInfo.resultList;
		} else {
			value = variableInfo.text;
		}
	} else if(attribute.type === "substituted") {
		value = this.wiki.getSubstitutedText(attribute.rawValue,this) || "";
		if(options.asList) {
			value = [value];
		}
	} else { // String attribute
		value = attribute.value;
		if(options.asList) {
			if(value === undefined) {
				value = [];
			} else {
				value = [value];
			}
		}
	}
	return value;
};

Widget.prototype.hasAttribute = function(name) {
	return $tw.utils.hop(this.attributes,name);
};

Widget.prototype.hasParseTreeNodeAttribute = function(name) {
	return $tw.utils.hop(this.parseTreeNode.attributes,name);
};

Widget.prototype.getAttribute = function(name,defaultText) {
	if($tw.utils.hop(this.attributes,name)) {
		return this.attributes[name];
	} else {
		return defaultText;
	}
};

Widget.prototype.assignAttributes = function(domNode,options) {
	options = options || {};
	var self = this,
		changedAttributes = options.changedAttributes || this.attributes,
		sourcePrefix = options.sourcePrefix || "",
		destPrefix = options.destPrefix || "",
		EVENT_ATTRIBUTE_PREFIX = "on";
	var assignAttribute = function(name,value) {
		// Process any CSS custom properties
		if(name.substr(0,2) === "--" && name.length > 2) {
			domNode.style.setProperty(name,value);
			return;
		}

		if(name.substr(0,6) === "style." && name.length > 6) {
			domNode.style[$tw.utils.unHyphenateCss(name.substr(6))] = value;
			return;
		}

		if(name.substr(0,sourcePrefix.length) === sourcePrefix) {
			name = destPrefix + name.substr(sourcePrefix.length);
		} else {
			value = undefined;
		}

		if(options.excludeEventAttributes && name.substr(0,2).toLowerCase() === EVENT_ATTRIBUTE_PREFIX) {
			value = undefined;
		}
		if(value !== undefined) {
			// Handle the xlink: namespace
			var namespace = null;
			if(name.substr(0,6) === "xlink:" && name.length > 6) {
				namespace = "http://www.w3.org/1999/xlink";
				name = name.substr(6);
			}

			try {
				domNode.setAttributeNS(namespace,name,value);
			} catch(e) {
			}
		}
	};
	// If the parse tree node has the orderedAttributes property then use that order
	if(this.parseTreeNode.orderedAttributes) {
		$tw.utils.each(this.parseTreeNode.orderedAttributes,function(attribute,index) {
			if(attribute.name in changedAttributes) {
				assignAttribute(attribute.name,self.getAttribute(attribute.name));
			}
		});
	// Otherwise update each changed attribute irrespective of order
	} else {
		$tw.utils.each(changedAttributes,function(value,name) {
			assignAttribute(name,self.getAttribute(name));
		});
	}
};

Widget.prototype.getAncestorCount = function() {
	if(this.ancestorCount === undefined) {
		if(this.parentWidget) {
			this.ancestorCount = this.parentWidget.getAncestorCount() + 1;
		} else {
			this.ancestorCount = 0;
		}
	}
	return this.ancestorCount;
};

Widget.prototype.makeChildWidgets = function(parseTreeNodes,options) {
	options = options || {};
	this.children = [];
	var self = this;
	// Check for too much recursion
	if(this.getAncestorCount() > $tw.utils.TranscludeRecursionError.MAX_WIDGET_TREE_DEPTH) {
		throw new $tw.utils.TranscludeRecursionError();
	} else {
		// Create set variable widgets for each variable
		$tw.utils.each(options.variables,function(value,name) {
			var setVariableWidget = {
				type: "set",
				attributes: {
					name: {type: "string", value: name},
					value: {type: "string", value: value}
				},
				children: parseTreeNodes
			};
			parseTreeNodes = [setVariableWidget];
		});
		// Create the child widgets
		$tw.utils.each(parseTreeNodes || (this.parseTreeNode && this.parseTreeNode.children),function(childNode) {
			self.children.push(self.makeChildWidget(childNode));
		});
	}
};

Widget.prototype.makeChildWidget = function(parseTreeNode,options) {
	var self = this;
	options = options || {};
	// Check whether this node type is defined by a custom widget definition
	var variableDefinitionName = "$" + parseTreeNode.type;
	if(this.variables[variableDefinitionName]) {
		var isOverrideable = function() {
				// Widget is overrideable if its name contains a period, or if it is an existing JS widget and we're not in safe mode
				return parseTreeNode.type.indexOf(".") !== -1 || (!!self.widgetClasses[parseTreeNode.type] && !$tw.safeMode);
			};
		if(!parseTreeNode.isNotRemappable && isOverrideable()) {
			var variableInfo = this.getVariableInfo(variableDefinitionName,{allowSelfAssigned: true});
			if(variableInfo && variableInfo.srcVariable && variableInfo.srcVariable.value && variableInfo.srcVariable.isWidgetDefinition) {
				var newParseTreeNode = {
					type: "transclude",
					children: parseTreeNode.children,
					isBlock: parseTreeNode.isBlock
				};
				$tw.utils.addAttributeToParseTreeNode(newParseTreeNode,"$variable",variableDefinitionName);
				$tw.utils.each(parseTreeNode.attributes,function(attr,name) {
					// If the attribute starts with a dollar then add an extra dollar so that it doesn't clash with the $xxx attributes of transclude
					name = name.charAt(0) === "$" ? "$" + name : name;
					$tw.utils.addAttributeToParseTreeNode(newParseTreeNode,$tw.utils.extend({},attr,{name: name}));
				});
				parseTreeNode = newParseTreeNode;
			}
		}
	}

	var WidgetClass = this.widgetClasses[parseTreeNode.type];
	if(!WidgetClass) {
		WidgetClass = this.widgetClasses.text;
		parseTreeNode = {type: "text", text: "Undefined widget '" + parseTreeNode.type + "'"};
	}

	$tw.utils.each(options.variables,function(value,name) {
		var setVariableWidget = {
			type: "set",
			attributes: {
				name: {type: "string", value: name},
				value: {type: "string", value: value}
			},
			children: [
				parseTreeNode
			]
		};
		parseTreeNode = setVariableWidget;
	});
	return new WidgetClass(parseTreeNode,{
		wiki: this.wiki,
		parentWidget: this,
		document: this.document
	});
};

Widget.prototype.nextSibling = function() {
	if(this.parentWidget) {
		var index = this.parentWidget.children.indexOf(this);
		if(index !== -1 && index < this.parentWidget.children.length-1) {
			return this.parentWidget.children[index+1];
		}
	}
	return null;
};

Widget.prototype.previousSibling = function() {
	if(this.parentWidget) {
		var index = this.parentWidget.children.indexOf(this);
		if(index !== -1 && index > 0) {
			return this.parentWidget.children[index-1];
		}
	}
	return null;
};

Widget.prototype.renderChildren = function(parent,nextSibling) {
	var children = this.children;
	for(var i = 0; i < children.length; i++) {
		children[i].render(parent,nextSibling);
	};
};

Widget.prototype.addEventListeners = function(listeners) {
	var self = this;
	$tw.utils.each(listeners,function(listenerInfo) {
		self.addEventListener(listenerInfo.type,listenerInfo.handler);
	});
};

Widget.prototype.addEventListener = function(type,handler) {
	this.eventListeners[type] = this.eventListeners[type] || [];
	if(this.eventListeners[type].indexOf(handler) === -1) {
		this.eventListeners[type].push(handler);
	}
};

Widget.prototype.removeEventListener = function(type,handler) {
	if(!this.eventListeners[type]) return;
	var index = this.eventListeners[type].indexOf(handler);
	if(index !== -1) {
		this.eventListeners[type].splice(index,1);
	}
};

Widget.prototype.dispatchEvent = function(event) {
	event.widget = event.widget || this;
	var listeners = this.eventListeners[event.type];
	if(listeners) {
		var self = this;
		var shouldPropagate = true;
		$tw.utils.each(listeners,function(handler) {
			var propagate;
			if(typeof handler === "string") {
				 // If handler is a string, call it as a method on the widget
				propagate = self[handler].call(self,event);
			} else {
				// Otherwise call the function handler directly
				propagate = handler.call(self,event);
			}
			if(propagate === false) {
				shouldPropagate = false;
			}
		});
		if(!shouldPropagate) {
			return false;
		}
	}

	if(this.parentWidget) {
		return this.parentWidget.dispatchEvent(event);
	}
	return true;
};

Widget.prototype.refresh = function(changedTiddlers) {
	return this.refreshChildren(changedTiddlers);
};

Widget.prototype.refreshSelf = function() {
	var nextSibling = this.findNextSiblingDomNode();
	this.removeChildDomNodes();
	this.render(this.parentDomNode,nextSibling);
};

Widget.prototype.refreshChildren = function(changedTiddlers) {
	var children = this.children,
		refreshed = false;
	for (var i = 0; i < children.length; i++) {
		refreshed = children[i].refresh(changedTiddlers) || refreshed;
	}
	return refreshed;
};

Widget.prototype.findNextSiblingDomNode = function(startIndex) {
	// Refer to this widget by its index within its parents children
	var parent = this.parentWidget,
		index = startIndex !== undefined ? startIndex : parent.children.indexOf(this);
	if(index === -1) {
		throw "node not found in parents children";
	}

	while(++index < parent.children.length) {
		var domNode = parent.children[index].findFirstDomNode();
		if(domNode) {
			return domNode;
		}
	}

	var grandParent = parent.parentWidget;
	if(grandParent && parent.parentDomNode === this.parentDomNode) {
		index = grandParent.children.indexOf(parent);
		if(index !== -1) {
			return parent.findNextSiblingDomNode(index);
		}
	}
	return null;
};

Widget.prototype.findFirstDomNode = function() {
	// Return the first dom node of this widget, if we've got one
	if(this.domNodes.length > 0) {
		return this.domNodes[0];
	}
	// Otherwise, recursively call our children
	for(var t=0; t<this.children.length; t++) {
		var domNode = this.children[t].findFirstDomNode();
		if(domNode) {
			return domNode;
		}
	}
	return null;
};

/*
Entry into destroy procedure
options include:
	removeDOMNodes: boolean (default true)
*/
Widget.prototype.destroyChildren = function(options) {
	$tw.utils.each(this.children,function(childWidget) {
		childWidget.destroy(options);
	});
};

/*
Legacy entry into destroy procedure
*/
Widget.prototype.removeChildDomNodes = function() {
	this.destroy({removeDOMNodes: true});
};

/*
Default destroy
options include:
- removeDOMNodes: boolean (default true)
*/
Widget.prototype.destroy = function(options) {
	const { removeDOMNodes = true } = options || {};
	let removeChildDOMNodes = removeDOMNodes;
	if(removeDOMNodes && this.domNodes.length > 0) {
		// If this widget will remove its own DOM nodes, children should not remove theirs
		removeChildDOMNodes = false;
	}
	// Destroy children first
	this.destroyChildren({removeDOMNodes: removeChildDOMNodes});
	this.children = [];

	// Call custom cleanup method if implemented
	if(typeof this.onDestroy === "function") {
		this.onDestroy();
	}

	// Remove our DOM nodes if needed
	if(removeDOMNodes) {
		this.removeLocalDomNodes();
	}
};

/*
Remove any DOM nodes created by this widget
*/
Widget.prototype.removeLocalDomNodes = function() {
	for(const domNode of this.domNodes) {
		if(domNode.parentNode) {
			domNode.parentNode.removeChild(domNode);
		}
	}
	this.domNodes = [];
};

/*
Invoke the action widgets that are descendents of the current widget.
*/
Widget.prototype.invokeActions = function(triggeringWidget,event) {
	var handled = false;
	// For each child widget
	for(var t=0; t<this.children.length; t++) {
		var child = this.children[t],
			childIsActionWidget = !!child.invokeAction,
			actionRefreshPolicy = child.getVariable("tv-action-refresh-policy"); // Default is "once"
		// Refresh the child if required
		if(childIsActionWidget || actionRefreshPolicy === "always") {
			child.refreshSelf();
		}
		// Invoke the child if it is an action widget
		if(childIsActionWidget) {
			if(child.invokeAction(triggeringWidget,event)) {
				handled = true;
			}
		}
		// Propagate through through the child if it permits it
		if(child.allowActionPropagation() && child.invokeActions(triggeringWidget,event)) {
			handled = true;
		}
	}
	return handled;
};

/*
Invoke the action widgets defined in a string
*/
Widget.prototype.invokeActionString = function(actions,triggeringWidget,event,variables) {
	actions = actions || "";
	var parser = this.wiki.parseText("text/vnd.tiddlywiki",actions,{
			parentWidget: this,
			document: this.document
		}),
		widgetNode = this.wiki.makeWidget(parser,{
			parentWidget: this,
			document: this.document,
			variables: variables
		});
	var container = this.document.createElement("div");
	widgetNode.render(container,null);
	return widgetNode.invokeActions(this,event);
};

/*
Execute action tiddlers by tag
*/
Widget.prototype.invokeActionsByTag = function(tag,event,variables) {
	var self = this;
	$tw.utils.each(self.wiki.filterTiddlers("[all[shadows+tiddlers]tag[" + tag + "]!has[draft.of]]"),function(title) {
		self.invokeActionString(self.wiki.getTiddlerText(title),self,event,variables);
	});
};

Widget.prototype.allowActionPropagation = function() {
	return true;
};

/*
Find child <$data> widgets recursively. The tag name allows aliased versions of the widget to be found too
*/
Widget.prototype.findChildrenDataWidgets = function(children,tag,callback) {
	var self = this;
	$tw.utils.each(children,function(child) {
		if(child.dataWidgetTag === tag) {
			callback(child);
		}
		if(child.children) {
			self.findChildrenDataWidgets(child.children,tag,callback);
		}
	});
};

/*
Evaluate a variable with parameters. This is a static convenience method that attempts to evaluate a variable as a function, returning an array of strings
*/
Widget.evaluateVariable  = function(widget,name,options) {
	var result;
	if(widget.getVariableInfo) {
		var variableInfo = widget.getVariableInfo(name,options);
		result = variableInfo.resultList || [variableInfo.text];
	} else {
		result = [widget.getVariable(name)];
	}
	return result;
};

exports.widget = Widget;