From 9e8d05f69905cbd3b79c19395f37542def4103b3 Mon Sep 17 00:00:00 2001
From: "jeremy@jermolene.com" <jeremy@jermolene.com>
Date: Mon, 23 May 2022 16:40:21 +0100
Subject: [PATCH] Require period prefix for custom filter operator functions

To ensure that custom filter operators cannot clash with future core operators.
---
 core/modules/filters/unknown.js               | 76 +++++++++----------
 .../custom-operators/NestedParameterised.tid  | 10 +--
 .../data/custom-operators/Parameterised.tid   |  6 +-
 .../tests/data/custom-operators/Simple.tid    |  4 +-
 4 files changed, 48 insertions(+), 48 deletions(-)

diff --git a/core/modules/filters/unknown.js b/core/modules/filters/unknown.js
index 2eca09a7c..81f868427 100644
--- a/core/modules/filters/unknown.js
+++ b/core/modules/filters/unknown.js
@@ -20,48 +20,48 @@ var fieldFilterOperatorFn = require("$:/core/modules/filters/field.js").field;
 Export our filter function
 */
 exports["[unknown]"] = function(source,operator,options) {
-	var customDefinitionTitle = "[" + operator.operator + "[]]",
-		customDefinition = options.widget && options.widget.getVariableInfo && options.widget.getVariableInfo(customDefinitionTitle);
-	if(customDefinition && customDefinition.srcVariable && customDefinition.srcVariable.isFunctionDefinition) {
-		var variables = Object.create(null);
-		$tw.utils.each(customDefinition.srcVariable.params,function(param,index) {
-			var value = operator.operands[index];
-			if(value === undefined) {
-				value = param["default"] || "";
-			}
-			variables[param.name] = value;
-		});
-		var getVariable = function(name,opts) {
-			if(name in variables) {
-				return variables[name];
-			} else {
-				return options.widget.getVariable(name,opts);
-			};
-		};
-		var getVariableInfo = function(name,opts) {
-			if(name in variables) {
-				return {
-					text: variables[name]
-				};
-			} else {
-				return options.widget.getVariableInfo(name,opts);
-			};
-		}
-		var list = options.wiki.filterTiddlers(customDefinition.srcVariable.value,{getVariable: getVariable,getVariableInfo: getVariableInfo},source);
-		if(operator.prefix === "!") {
-			var results = [];
-			source(function(tiddler,title) {
-				if(list.indexOf(title) === -1) {
-					results.push(title);
+	if(operator.operator.charAt(0) === ".") {
+		var customDefinition = options.widget && options.widget.getVariableInfo && options.widget.getVariableInfo(operator.operator);
+		if(customDefinition && customDefinition.srcVariable && customDefinition.srcVariable.isFunctionDefinition) {
+			var variables = Object.create(null);
+			$tw.utils.each(customDefinition.srcVariable.params,function(param,index) {
+				var value = operator.operands[index];
+				if(value === undefined) {
+					value = param["default"] || "";
 				}
+				variables[param.name] = value;
 			});
-			return results;
-		} else {
-			return list;
+			var getVariable = function(name,opts) {
+				if(name in variables) {
+					return variables[name];
+				} else {
+					return options.widget.getVariable(name,opts);
+				};
+			};
+			var getVariableInfo = function(name,opts) {
+				if(name in variables) {
+					return {
+						text: variables[name]
+					};
+				} else {
+					return options.widget.getVariableInfo(name,opts);
+				};
+			}
+			var list = options.wiki.filterTiddlers(customDefinition.srcVariable.value,{getVariable: getVariable,getVariableInfo: getVariableInfo},source);
+			if(operator.prefix === "!") {
+				var results = [];
+				source(function(tiddler,title) {
+					if(list.indexOf(title) === -1) {
+						results.push(title);
+					}
+				});
+				return results;
+			} else {
+				return list;
+			}
 		}
-	} else {
-		return fieldFilterOperatorFn(source,operator,options);
 	}
+	return fieldFilterOperatorFn(source,operator,options);
 };
 
 })();
diff --git a/editions/test/tiddlers/tests/data/custom-operators/NestedParameterised.tid b/editions/test/tiddlers/tests/data/custom-operators/NestedParameterised.tid
index cbeb1570d..3e4d610d0 100644
--- a/editions/test/tiddlers/tests/data/custom-operators/NestedParameterised.tid
+++ b/editions/test/tiddlers/tests/data/custom-operators/NestedParameterised.tid
@@ -6,17 +6,17 @@ tags: [[$:/tags/wiki-test-spec]]
 title: Output
 
 \whitespace trim
-\function [dividebysomething[]](first:ignored,factor:0.5)
+\function .dividebysomething(first:ignored,factor:0.5)
 [divide[2]multiply<factor>]
 \end
 
-\function [multiplebysomething[]](first:ignored,factor:2)
-[multiply[2]dividebysomething[],<factor>]
+\function .multiplebysomething(first:ignored,factor:2)
+[multiply[2].dividebysomething[],<factor>]
 \end
 
-<$text text={{{ [[123]multiplebysomething[]] }}}/>
+<$text text={{{ [[123].multiplebysomething[]] }}}/>
 -
-<$text text={{{ [[123]multiplebysomething[x],[4]] }}}/>
+<$text text={{{ [[123].multiplebysomething[x],[4]] }}}/>
 
 +
 title: ExpectedResult
diff --git a/editions/test/tiddlers/tests/data/custom-operators/Parameterised.tid b/editions/test/tiddlers/tests/data/custom-operators/Parameterised.tid
index 42ca40ec6..6901710b7 100644
--- a/editions/test/tiddlers/tests/data/custom-operators/Parameterised.tid
+++ b/editions/test/tiddlers/tests/data/custom-operators/Parameterised.tid
@@ -6,13 +6,13 @@ tags: [[$:/tags/wiki-test-spec]]
 title: Output
 
 \whitespace trim
-\function [multiplybysomething[]](first:ignored,factor:2)
+\function .multiplybysomething(first:ignored,factor:2)
 [multiply[2]multiply<factor>]
 \end
 
-<$text text={{{ [[123]multiplybysomething[]] }}}/>
+<$text text={{{ [[123].multiplybysomething[]] }}}/>
 -
-<$text text={{{ [[123]multiplybysomething[x],[4]] }}}/>
+<$text text={{{ [[123].multiplybysomething[x],[4]] }}}/>
 
 +
 title: ExpectedResult
diff --git a/editions/test/tiddlers/tests/data/custom-operators/Simple.tid b/editions/test/tiddlers/tests/data/custom-operators/Simple.tid
index 076a54dad..73d46d689 100644
--- a/editions/test/tiddlers/tests/data/custom-operators/Simple.tid
+++ b/editions/test/tiddlers/tests/data/custom-operators/Simple.tid
@@ -5,11 +5,11 @@ tags: [[$:/tags/wiki-test-spec]]
 
 title: Output
 
-\function [multiplybytwo[]]()
+\function .multiplybytwo()
 [multiply[2]]
 \end
 
-<$text text={{{ [[123]multiplybytwo[]] }}}/>
+<$text text={{{ [[123].multiplybytwo[]] }}}/>
 +
 title: ExpectedResult