97 lines
2.5 KiB
JavaScript
97 lines
2.5 KiB
JavaScript
/*\
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title: $:/core/modules/widgets/let.js
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type: application/javascript
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module-type: widget
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This widget allows defining multiple variables at once, while allowing
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the later variables to depend upon the earlier ones.
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```
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\define helloworld() Hello world!
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<$let currentTiddler="target" value={{!!value}} currentTiddler="different">
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{{!!value}} will be different from <<value>>
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</$let>
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```
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\*/
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(function(){
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/*jslint node: true, browser: true */
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/*global $tw: false */
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"use strict";
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var Widget = require("$:/core/modules/widgets/widget.js").widget;
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var LetWidget = function(parseTreeNode,options) {
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// Initialise
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this.initialise(parseTreeNode,options);
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};
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/*
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Inherit from the base widget class
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*/
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LetWidget.prototype = new Widget();
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/*
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Render this widget into the DOM
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*/
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LetWidget.prototype.render = function(parent,nextSibling) {
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this.parentDomNode = parent;
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this.computeAttributes();
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this.execute();
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this.renderChildren(parent,nextSibling);
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};
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LetWidget.prototype.computeAttributes = function() {
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// Before computing attributes, we must make clear that none of the
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// existing attributes are staged for lookup, even on a refresh
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var changedAttributes = {},
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self = this;
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this.currentValueFor = Object.create(null);
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$tw.utils.each($tw.utils.getOrderedAttributesFromParseTreeNode(this.parseTreeNode),function(attribute) {
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var value = self.computeAttribute(attribute),
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name = attribute.name;
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if(name.charAt(0) !== "$") {
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// Now that it's prepped, we're allowed to look this variable up
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// when defining later variables
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self.currentValueFor[name] = value;
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}
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});
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// Run through again, setting variables and looking for differences
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$tw.utils.each(this.currentValueFor,function(value,name) {
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if (self.attributes[name] !== value) {
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self.attributes[name] = value;
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self.setVariable(name,value);
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changedAttributes[name] = true;
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}
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});
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return changedAttributes;
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};
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LetWidget.prototype.getVariableInfo = function(name,options) {
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// Special handling: If this variable exists in this very $let, we can
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// use it, but only if it's been staged.
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if ($tw.utils.hop(this.currentValueFor,name)) {
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return {
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text: this.currentValueFor[name]
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};
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}
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return Widget.prototype.getVariableInfo.call(this,name,options);
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};
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/*
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Refresh the widget by ensuring our attributes are up to date
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*/
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LetWidget.prototype.refresh = function(changedTiddlers) {
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var changedAttributes = this.computeAttributes();
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if($tw.utils.count(changedAttributes) > 0) {
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this.refreshSelf();
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return true;
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}
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return this.refreshChildren(changedTiddlers);
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};
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exports["let"] = LetWidget;
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})();
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