Minor refactoring

core/modules/filters.js

@@ -8,23 +8,23 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 \*/
 (function(){
 
-	/*jslint node: true, browser: true */
+/*jslint node: true, browser: true */
-	/*global $tw: false */
+/*global $tw: false */
-	"use strict";
+"use strict";
 
-	var widgetClass = require("$:/core/modules/widgets/widget.js").widget;
+var widgetClass = require("$:/core/modules/widgets/widget.js").widget;
 
-	/* Maximum permitted filter recursion depth */
+/* Maximum permitted filter recursion depth */
-	var MAX_FILTER_DEPTH = 300;
+var MAX_FILTER_DEPTH = 300;
 
-	/*
+/*
-	Parses an operation (i.e. a run) within a filter string
+Parses an operation (i.e. a run) within a filter string
 	operators: Array of array of operator nodes into which results should be inserted
 	filterString: filter string
 	p: start position within the string
-	Returns the new start position, after the parsed operation
+Returns the new start position, after the parsed operation
-	*/
+*/
-	function parseFilterOperation(operators,filterString,p) {
+function parseFilterOperation(operators,filterString,p) {
 	var nextBracketPos, operator;
 	// Skip the starting square bracket
 	if(filterString.charAt(p++) !== "[") {
@@ -133,12 +133,12 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 	}
 	// Return the parsing position
 	return p;
-	}
+}
 
-	/*
+/*
-	Parse a filter string
+Parse a filter string
-	*/
+*/
-	exports.parseFilter = function(filterString) {
+exports.parseFilter = function(filterString) {
 	filterString = filterString || "";
 	var results = [], // Array of arrays of operator nodes {operator:,operand:}
 		p = 0, // Current position in the filter string
@@ -196,42 +196,45 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 		}
 	}
 	return results;
-	};
+};
 
-	exports.getFilterOperators = function() {
+exports.getFilterOperators = function() {
 	if(!this.filterOperators) {
 		$tw.Wiki.prototype.filterOperators = {};
 		$tw.modules.applyMethods("filteroperator",this.filterOperators);
 	}
 	return this.filterOperators;
-	};
+};
 
-	exports.getFilterRunPrefixes = function() {
+exports.getFilterRunPrefixes = function() {
 	if(!this.filterRunPrefixes) {
 		$tw.Wiki.prototype.filterRunPrefixes = {};
 		$tw.modules.applyMethods("filterrunprefix",this.filterRunPrefixes);
 	}
 	return this.filterRunPrefixes;
-	}
+}
 
-	exports.filterTiddlers = function(filterString,widget,source) {
+exports.filterTiddlers = function(filterString,widget,source) {
 	var fn = this.compileFilter(filterString);
 	return fn.call(this,source,widget);
-	};
+};
 
-	/*
+/*
-	Compile a filter into a function with the signature fn(source,widget) where:
+Compile a filter into a function with the signature fn(source,widget) where:
-	source: an iterator function for the source tiddlers, called source(iterator), where iterator is called as iterator(tiddler,title)
+source: an iterator function for the source tiddlers, called source(iterator), where iterator is called as iterator(tiddler,title)
-	widget: an optional widget node for retrieving the current tiddler etc.
+widget: an optional widget node for retrieving the current tiddler etc.
-	*/
+*/
-	exports.compileFilter = function(filterString) {
+exports.compileFilter = function(filterString) {
+	// Set up the filter function cache
 	if(!this.filterCache) {
 		this.filterCache = Object.create(null);
 		this.filterCacheCount = 0;
 	}
+	// Use the cached version of this filter function if it exists
 	if(this.filterCache[filterString] !== undefined) {
 		return this.filterCache[filterString];
 	}
+	// Parse the filter string
 	var filterParseTree;
 	try {
 		filterParseTree = this.parseFilter(filterString);
@@ -334,8 +337,8 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 			}
 		})());
 	});
-		// Return a function that applies the operations to a source iterator of tiddler titles
+	// Make the filter function
-		var fnMeasured = $tw.perf.measure("filter: " + filterString,function filterFunction(source,widget) {
+	var fnFilter = function filterFunction(source,widget) {
 		if(!source) {
 			source = self.each;
 		} else if(typeof source === "object") { // Array or hashmap
@@ -355,7 +358,10 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 		}
 		self.filterRecursionCount = self.filterRecursionCount - 1;
 		return results.toArray();
-		});
+	};
+	// Return a function that applies the operations to a source iterator of tiddler titles
+	var fnMeasured = $tw.perf.measure("filter: " + filterString,fnFilter);
+	// Cache the measured filter function
 	if(this.filterCacheCount >= 2000) {
 		// To prevent memory leak, we maintain an upper limit for cache size.
 		// Reset if exceeded. This should give us 95% of the benefit
@@ -366,7 +372,7 @@ Adds tiddler filtering methods to the $tw.Wiki object.
 	this.filterCache[filterString] = fnMeasured;
 	this.filterCacheCount++;
 	return fnMeasured;
-	};
+};
 
-	})();
+})();