Add apply filter run prefix

The map filter run prefix is often used as a way to move a computed value in the input list into a variable so that it can be used as a parameter of a filter operator. The apply filter run prefix extends this idea to make the input list available as variables $1, $2 etc. Unlike the map prefix, the apply filter run is only evaluated once.

core/modules/filterrunprefixes/apply.js

@@ -0,0 +1,29 @@
+/*\
+title: $:/core/modules/filterrunprefixes/apply.js
+type: application/javascript
+module-type: filterrunprefix
+
+
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.apply = function(operationSubFunction) {
+	return function(results,source,widget) {
+		source = widget.wiki.makeTiddlerIterator([]);
+		var variables = {},
+			counter = 1;
+		results.each(function(title) {
+			variables["$" + counter] = title;
+			counter++;
+		});
+		results.clear();
+		results.pushTop(operationSubFunction(source,widget.makeFakeWidgetWithVariables(variables)));
+	};
+};
+
+})();

editions/test/tiddlers/tests/data/filters/FilterRunPrefixesApply.tid

@@ -0,0 +1,13 @@
+title: Filters/FilterRunPrefixes/Applu
+description: Applu filter run prefix
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+<$text text={{{ a b c :apply[<$1>addsuffix<$2>addsuffix<$3>] }}}/>
++
+title: ExpectedResult
+
+<p>abc</p>