Add "match" operator for string comparison

Fixes #4130

core/modules/filters/match.js

@@ -0,0 +1,53 @@
+/*\
+title: $:/core/modules/filters/match.js
+type: application/javascript
+module-type: filteroperator
+
+Filter operator for checking if a title matches a string
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Export our filter function
+*/
+exports.match = function(source,operator,options) {
+	var results = [],
+		suffixes = (operator.suffixes || [])[0] || [];
+	if(suffixes.indexOf("caseinsensitive") !== -1) {
+		if(operator.prefix === "!") {
+			source(function(tiddler,title) {
+				if(title.toLowerCase() !== (operator.operand || "").toLowerCase()) {
+					results.push(title);
+				}
+			});
+		} else {
+			source(function(tiddler,title) {
+				if(title.toLowerCase() === (operator.operand || "").toLowerCase()) {
+					results.push(title);
+				}
+			});
+		}
+	} else {
+		if(operator.prefix === "!") {
+			source(function(tiddler,title) {
+				if(title !== operator.operand) {
+					results.push(title);
+				}
+			});
+		} else {
+			source(function(tiddler,title) {
+				if(title === operator.operand) {
+					results.push(title);
+				}
+			});
+		}
+	}
+	return results;
+};
+
+})();

editions/prerelease/tiddlers/Release 5.1.20.tid

@@ -11,7 +11,7 @@ type: text/vnd.tiddlywiki
 
 Added several new [[Mathematics Operators]] for working with numbers: [[negate|negate Operator]], [[abs|abs Operator]], [[ceil|ceil Operator]], [[floor|floor Operator]], [[round|round Operator]], [[trunc|trunc Operator]], [[untrunc|untrunc Operator]], [[sign|sign Operator]], [[add|add Operator]], [[subtract|subtract Operator]], [[multiply|multiply Operator]], [[divide|divide Operator]], [[remainder|remainder Operator]], [[max|max Operator]], [[min|min Operator]], [[fixed|fixed Operator]], [[precision|precision Operator]], [[exponential|exponential Operator]], [[sum|sum Operator]], [[product|product Operator]], [[maxall|maxall Operator]] and [[minall|minall Operator]].
 
-Added several new string operators: [[length|length Operator]], [[uppercase|uppercase Operator]], [[lowercase|lowercase Operator]], [[titlecase|titlecase Operator]], [[sentencecase|sentencecase Operator]], [[trim|trim Operator]], [[split|split Operator]], [[splitregexp|splitregexp Operator]] and [[join|join Operator]].
+Added several new string operators: [[match|match Operator]], [[length|length Operator]], [[uppercase|uppercase Operator]], [[lowercase|lowercase Operator]], [[titlecase|titlecase Operator]], [[sentencecase|sentencecase Operator]], [[trim|trim Operator]], [[split|split Operator]], [[splitregexp|splitregexp Operator]] and [[join|join Operator]].
 
 There is now finer control over TiddlyWiki's default behaviour of removing duplicates from filter results, making it much easier to work with the new mathematics and string operators:
 

editions/test/tiddlers/tests/test-filters.js

@@ -238,6 +238,16 @@ function runTests(wiki) {
 		expect(wiki.filterTiddlers("[[TiddlerOne]tags[]sort[title]]").join(",")).toBe("one");
 	});
 
+	it("should handle the match operator", function() {
+		expect(wiki.filterTiddlers("[match[TiddlerOne]]").join(",")).toBe("TiddlerOne");
+		expect(wiki.filterTiddlers("TiddlerOne TiddlerOne =[match[TiddlerOne]]").join(",")).toBe("TiddlerOne,TiddlerOne");
+		expect(wiki.filterTiddlers("[!match[TiddlerOne]]").join(",")).toBe("$:/ShadowPlugin,$:/TiddlerTwo,Tiddler Three,a fourth tiddler,one");
+		expect(wiki.filterTiddlers("[match:casesensitive[tiddlerone]]").join(",")).toBe("");
+		expect(wiki.filterTiddlers("[!match:casesensitive[tiddlerone]]").join(",")).toBe("$:/ShadowPlugin,TiddlerOne,$:/TiddlerTwo,Tiddler Three,a fourth tiddler,one");
+		expect(wiki.filterTiddlers("[match:caseinsensitive[tiddlerone]]").join(",")).toBe("TiddlerOne");
+		expect(wiki.filterTiddlers("[!match:caseinsensitive[tiddlerone]]").join(",")).toBe("$:/ShadowPlugin,$:/TiddlerTwo,Tiddler Three,a fourth tiddler,one");
+	});
+
 	it("should handle the tagging operator", function() {
 		expect(wiki.filterTiddlers("[[one]tagging[]sort[title]]").join(",")).toBe("Tiddler Three,Tiddler8,TiddlerOne,TiddlerSeventh");
 		expect(wiki.filterTiddlers("[[one]tagging[]]").join(",")).toBe("Tiddler Three,TiddlerOne,TiddlerSeventh,Tiddler8");

editions/tw5.com/tiddlers/filters/examples/match Operator (Examples).tid

@@ -0,0 +1,8 @@
+created: 20190731080350471
+modified: 20190731080435966
+tags: [[match Operator]] [[Operator Examples]]
+title: match Operator (Examples)
+type: text/vnd.tiddlywiki
+
+<<.operator-example 1 "a b c +[match[b]]">>
+<<.operator-example 1 "[match[HelloThere]]">>

editions/tw5.com/tiddlers/filters/match Operator.tid

@@ -0,0 +1,30 @@
+caption: match
+created: 20190731080209404
+modified: 20190731081047732
+op-input: a [[selection of titles|Title Selection]]
+op-neg-output: each item in the input list that does not match the operand string
+op-output: each item in the input list that matches the operand string (potentially including duplicates)
+op-parameter: the string to be matched
+op-purpose: returns each item in the list that matches the operand string
+op-suffix: the <<.op match>> operator uses a rich suffix, see below for details
+tags: [[Filter Operators]]
+title: match Operator
+type: text/vnd.tiddlywiki
+
+<<.from-version "5.1.20">>
+
+The <<.op match>> operator uses an extended syntax that permits multiple flags to be passed:
+
+```
+[match:<flag list>[<operand>]]
+```
+
+* ''flag list'': a comma delimited list of flags
+* ''operand'': filter operand
+
+The available flags are:
+
+* ''casesensitive'': (default), this flag forces a case-sensitive match, where upper and lower case letters are considered different
+* "caseinsensitive". overrides the default so that upper and lower case letters are considered identical for matching purposes
+
+<<.operator-examples "match">>