Introduce true global variables

The basic idea is that if we don't find a variable `foo` then we fallback to retrieving the value from the tiddler `$:/global/foo`, if it exists.

This allows us to replace the usual importvariables-based mechanism for global definitions, avoiding cluttering up the variable namespace with every macro.

In order to permit subprocedures to be overridden, we also introduce a mechanism for conditional definitions: preceding the word definition|procedure|function|widget with a + causes the definition only to occur if the specified variable doesn't already exist. In the next commit we'll apply this mechanism to the tabs macro

core/modules/parsers/wikiparser/rules/fnprocdef.js

@@ -35,7 +35,7 @@ Instantiate parse rule
 exports.init = function(parser) {
 	this.parser = parser;
 	// Regexp to match
-	this.matchRegExp = /^\\(function|procedure|widget)\s+([^(\s]+)(\(\s*([^)]*)\))?(\s*\r?\n)?/mg;
+	this.matchRegExp = /^\\(\+?)(function|procedure|widget)\s+([^(\s]+)(\(\s*([^)]*)\))?(\s*\r?\n)?/mg;
 };
 
 /*
@@ -46,12 +46,12 @@ exports.parse = function() {
 	this.parser.pos = this.matchRegExp.lastIndex;
 	// Parse the parameters
 	var params = [];
-	if(this.match[3]) {
-		params = $tw.utils.parseParameterDefinition(this.match[4]);
+	if(this.match[4]) {
+		params = $tw.utils.parseParameterDefinition(this.match[5]);
 	}
 	// Is this a multiline definition?
 	var reEnd;
-	if(this.match[5]) {
+	if(this.match[6]) {
 		// If so, the end of the body is marked with \end
 		reEnd = /(\r?\n\\end[^\S\n\r]*(?:$|\r?\n))/mg;
 	} else {
@@ -75,22 +75,25 @@ exports.parse = function() {
 	var parseTreeNodes = [{
 		type: "set",
 		attributes: {
-			name: {type: "string", value: this.match[2]},
+			name: {type: "string", value: this.match[3]},
 			value: {type: "string", value: text}
 		},
 		children: [],
 		params: params
 	}];
-	if(this.match[1] === "function") {
+	if(this.match[2] === "function") {
 		parseTreeNodes[0].isFunctionDefinition = true;
-	} else if(this.match[1] === "procedure") {
+	} else if(this.match[2] === "procedure") {
 		parseTreeNodes[0].isProcedureDefinition = true;
-	} else if(this.match[1] === "widget") {
+	} else if(this.match[2] === "widget") {
 		parseTreeNodes[0].isWidgetDefinition = true;
 	}
 	if(this.parser.configTrimWhiteSpace) {
 		parseTreeNodes[0].configTrimWhiteSpace = true;
 	}
+	if(this.match[1] === "+") {
+		$tw.utils.addAttributeToParseTreeNode(parseTreeNodes[0],"conditional","yes");
+	}
 	return parseTreeNodes;
 };
 

core/modules/parsers/wikiparser/rules/macrodef.js

@@ -27,7 +27,7 @@ Instantiate parse rule
 exports.init = function(parser) {
 	this.parser = parser;
 	// Regexp to match
-	this.matchRegExp = /^\\define\s+([^(\s]+)\(\s*([^)]*)\)(\s*\r?\n)?/mg;
+	this.matchRegExp = /^\\(\+?)define\s+([^(\s]+)\(\s*([^)]*)\)(\s*\r?\n)?/mg;
 };
 
 /*
@@ -37,7 +37,7 @@ exports.parse = function() {
 	// Move past the macro name and parameters
 	this.parser.pos = this.matchRegExp.lastIndex;
 	// Parse the parameters
-	var paramString = this.match[2],
+	var paramString = this.match[3],
 		params = [];
 	if(paramString !== "") {
 		var reParam = /\s*([A-Za-z0-9\-_]+)(?:\s*:\s*(?:"""([\s\S]*?)"""|"([^"]*)"|'([^']*)'|\[\[([^\]]*)\]\]|([^"'\s]+)))?/mg,
@@ -56,7 +56,7 @@ exports.parse = function() {
 	}
 	// Is this a multiline definition?
 	var reEnd;
-	if(this.match[3]) {
+	if(this.match[4]) {
 		// If so, the end of the body is marked with \end
 		reEnd = /(\r?\n\\end[^\S\n\r]*(?:$|\r?\n))/mg;
 	} else {
@@ -77,16 +77,22 @@ exports.parse = function() {
 		text = "";
 	}
 	// Save the macro definition
-	return [{
+	var parseTreeNodes = [{
 		type: "set",
 		attributes: {
-			name: {type: "string", value: this.match[1]},
+			name: {type: "string", value: this.match[2]},
 			value: {type: "string", value: text}
 		},
 		children: [],
 		params: params,
 		isMacroDefinition: true
 	}];
+	$tw.utils.addAttributeToParseTreeNode(parseTreeNodes[0],"name",this.match[2]);
+	$tw.utils.addAttributeToParseTreeNode(parseTreeNodes[0],"value",text);
+	if(this.match[1] === "+") {
+		$tw.utils.addAttributeToParseTreeNode(parseTreeNodes[0],"conditional","yes");
+	}
+	return parseTreeNodes;
 };
 
 })();

core/modules/widgets/setvariable.js

@@ -47,17 +47,20 @@ SetWidget.prototype.execute = function() {
 	this.setIndex = this.getAttribute("index");
 	this.setValue = this.getAttribute("value");
 	this.setEmptyValue = this.getAttribute("emptyValue");
-	// Set context variable
-	if(this.parseTreeNode.isMacroDefinition) {
-		this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,true);
-	} else if(this.parseTreeNode.isFunctionDefinition) {
-		this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isFunctionDefinition: true});
-	} else if(this.parseTreeNode.isProcedureDefinition) {
-		this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isProcedureDefinition: true, configTrimWhiteSpace: this.parseTreeNode.configTrimWhiteSpace});
-	} else if(this.parseTreeNode.isWidgetDefinition) {
-		this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isWidgetDefinition: true, configTrimWhiteSpace: this.parseTreeNode.configTrimWhiteSpace});
-	} else {
-		this.setVariable(this.setName,this.getValue());
+	this.setConditional = this.getAttribute("conditional","no") === "yes";
+	// Set context variable, checking for a conditional assignment
+	if(!this.setConditional || this.getVariableInfo(this.setName).text === undefined) {
+		if(this.parseTreeNode.isMacroDefinition) {
+			this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,true);
+		} else if(this.parseTreeNode.isFunctionDefinition) {
+			this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isFunctionDefinition: true});
+		} else if(this.parseTreeNode.isProcedureDefinition) {
+			this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isProcedureDefinition: true, configTrimWhiteSpace: this.parseTreeNode.configTrimWhiteSpace});
+		} else if(this.parseTreeNode.isWidgetDefinition) {
+			this.setVariable(this.setName,this.getValue(),this.parseTreeNode.params,undefined,{isWidgetDefinition: true, configTrimWhiteSpace: this.parseTreeNode.configTrimWhiteSpace});
+		} else {
+			this.setVariable(this.setName,this.getValue());
+		}
 	}
 	// Construct the child widgets
 	this.makeChildWidgets();
@@ -111,7 +114,7 @@ Selectively refreshes the widget if needed. Returns true if the widget or any of
 */
 SetWidget.prototype.refresh = function(changedTiddlers) {
 	var changedAttributes = this.computeAttributes();
-	if(changedAttributes.name || changedAttributes.filter || changedAttributes.select || changedAttributes.tiddler || (this.setTiddler && changedTiddlers[this.setTiddler]) || changedAttributes.field || changedAttributes.index || changedAttributes.value || changedAttributes.emptyValue ||
+	if(changedAttributes.name || changedAttributes.filter || changedAttributes.select || changedAttributes.tiddler || (this.setTiddler && changedTiddlers[this.setTiddler]) || changedAttributes.field || changedAttributes.index || changedAttributes.value || changedAttributes.emptyValue || changedAttributes.conditional ||
 	   (this.setFilter && this.getValue() != this.variables[this.setName].value)) {
 		this.refreshSelf();
 		return true;

core/modules/widgets/widget.js

@@ -116,6 +116,7 @@ options: see below
 Options include
 params: array of {name:, value:} for each parameter
 defaultValue: default value if the variable is not defined
+allowSelfAssigned: if true, includes the current widget in the context chain instead of just the parent
 
 Returns an object with the following fields:
 
@@ -124,32 +125,54 @@ text: text of variable, with parameters properly substituted
 */
 Widget.prototype.getVariableInfo = function(name,options) {
 	options = options || {};
-	var actualParams = options.params || [],
-		parentWidget = this.parentWidget;
-	// Check for the variable defined in the parent widget (or an ancestor in the prototype chain)
-	if(parentWidget && name in parentWidget.variables) {
-		var variable = parentWidget.variables[name],
-			originalValue = variable.value,
-			value = originalValue;
-		// Only substitute parameter and variable references if this variable was defined with the \define pragma
-		if(variable.isMacroDefinition) {
-			var params = this.resolveVariableParameters(variable.params,actualParams);
-			// Substitute any parameters specified in the definition
-			$tw.utils.each(params,function(param) {
-				value = $tw.utils.replaceString(value,new RegExp("\\$" + $tw.utils.escapeRegExp(param.name) + "\\$","mg"),param.value);
-			});
-			value = this.substituteVariableReferences(value,options);
-		}
-		return {
-			text: value,
-			params: params,
-			srcVariable: variable,
-			isCacheable: originalValue === value
+	var self = this,
+		actualParams = options.params || [],
+		currWidget = options.allowSelfAssigned ? this : this.parentWidget,
+		processVariable = function(variable) {
+			var originalValue = variable.value,
+				value = originalValue,
+				params = [];
+			// Only substitute parameter and variable references if this variable was defined with the \define pragma
+			if(variable.isMacroDefinition) {
+				params = self.resolveVariableParameters(variable.params,actualParams);
+				// Substitute any parameters specified in the definition
+				$tw.utils.each(params,function(param) {
+					value = $tw.utils.replaceString(value,new RegExp("\\$" + $tw.utils.escapeRegExp(param.name) + "\\$","mg"),param.value);
+				});
+				value = self.substituteVariableReferences(value,options);
+			}
+			return {
+				text: value,
+				params: params,
+				srcVariable: variable,
+				isCacheable: originalValue === value
+			};
 		};
+	// Check for the variable defined in the parent widget (or an ancestor in the prototype chain)
+	if(currWidget && name in currWidget.variables) {
+		return processVariable(currWidget.variables[name]);
 	}
 	// If the variable doesn't exist in the parent widget then look for a macro module
+	var text = this.evaluateMacroModule(name,actualParams);
+	if(text === undefined) {
+		// Check for a shadow variable tiddler
+		var tiddler = this.wiki.getTiddler("$:/global/" + name);
+		if(tiddler) {
+			return processVariable({
+				value: tiddler.getFieldString("text"),
+				params: $tw.utils.parseParameterDefinition(tiddler.getFieldString("parameters"),{requireParenthesis: true}),
+				isMacroDefinition: tiddler.getFieldString("is-macro") === "yes",
+				isWidgetDefinition: tiddler.getFieldString("is-widget") === "yes",
+				isProcedureDefinition: tiddler.getFieldString("is-procedure") === "yes",
+				isFunctionDefinition: tiddler.getFieldString("is-function") === "yes"
+			});
+		}
+	}
+	if(text === undefined) {
+		text = options.defaultValue;
+	}
 	return {
-		text: this.evaluateMacroModule(name,actualParams,options.defaultValue),
+		text: text,
 		srcVariable: {}
 	};
 };
@@ -479,12 +502,12 @@ Widget.prototype.makeChildWidget = function(parseTreeNode,options) {
 	options = options || {};
 	// Check whether this node type is defined by a custom widget definition
 	var variableDefinitionName = "$" + parseTreeNode.type,
-		variableInfo = this.variables[variableDefinitionName],
+		variableInfo = this.getVariableInfo(variableDefinitionName,{allowSelfAssigned: true}),
 		isOverrideable = function() {
 			// Widget is overrideable if it has a double dollar user defined name, or if it is an existing JS widget
 			return parseTreeNode.type.charAt(0) === "$" || !!self.widgetClasses[parseTreeNode.type];
 		};
-	if(!parseTreeNode.isNotRemappable && isOverrideable() && variableInfo && variableInfo.value && variableInfo.isWidgetDefinition) {
+	if(!parseTreeNode.isNotRemappable && isOverrideable() && variableInfo && variableInfo.srcVariable && variableInfo.srcVariable.value && variableInfo.srcVariable.isWidgetDefinition) {
 		var newParseTreeNode = {
 			type: "transclude",
 			children: [

editions/test/tiddlers/tests/data/globals/CustomWidget.tid

@@ -0,0 +1,22 @@
+title: Globals/CustomWidget
+description: Global shadow variable defining a custom widget
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+
+<$$mywidget foo="Mahogany">
+Sycamore!
+</$$mywidget>
++
+title: $:/global/$$mywidget
+is-widget: yes
+parameters: (foo:"bar")
+
+Koala! <$text text=<<foo>>/>, <$slot $name="ts-body"/>
++
+title: ExpectedResult
+
+<p>Koala! Mahogany, Sycamore!</p>

editions/test/tiddlers/tests/data/globals/Functions.tid

@@ -0,0 +1,22 @@
+title: Globals/Functions
+description: Global functions in shadow variables
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+
+<$text text=<<this-is-one>>/>
+|
+<$text text=<<this-is-one 7>>/>
++
+title: $:/global/this-is-one
+is-function: yes
+parameters: (foo:"2")
+
+[<foo>multiply[2.5]]
++
+title: ExpectedResult
+
+<p>5|17.5</p>

editions/test/tiddlers/tests/data/globals/Procedures.tid

@@ -0,0 +1,27 @@
+title: Globals/Procedures
+description: Global procedures in shadow variables
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+
+<<this-is-one>>
+|
+<<this-is-one blah>>
++
+title: $:/global/this-is-one
+
+\whitespace trim
+
+\procedure example()
+ONE
+\end
+
+\parameters (foo:"nothing")
+<<example>>-<$text text=<<foo>>/>
++
+title: ExpectedResult
+
+<p>ONE-nothing</p><p>|ONE-blah</p>

editions/test/tiddlers/tests/data/globals/ProceduresWithConditionalDefinitions.tid

@@ -0,0 +1,26 @@
+title: Globals/ProceduresWithConditionalDefinitions
+description: Global procedures with conditional definitions to allow overriding
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+
+<<this-is-one>>|<<this-is-one blah>>~
+<$let example="TWO"><<this-is-one>>|<<this-is-one blah>></$let>
++
+title: $:/global/this-is-one
+
+\whitespace trim
+
+\+procedure example()
+ONE
+\end
+
+\parameters (foo:"nothing")
+<<example>>-<$text text=<<foo>>/>
++
+title: ExpectedResult
+
+<p>ONE-nothing|ONE-blah~TWO-nothing|TWO-blah</p>

editions/test/tiddlers/tests/test-wikitext-parser.js

@@ -114,7 +114,7 @@ describe("WikiText parser tests", function() {
 	it("should parse macro definitions", function() {
 		expect(parse("\\define myMacro()\nnothing\n\\end\n")).toEqual(
 
-			[ { type : 'set', attributes : { name : { type : 'string', value : 'myMacro' }, value : { type : 'string', value : 'nothing' } }, children : [  ], params : [  ], isMacroDefinition : true } ]
+			[{"type":"set","attributes":{"name":{"name":"name","type":"string","value":"myMacro"},"value":{"name":"value","type":"string","value":"nothing"}},"children":[],"params":[],"isMacroDefinition":true,"orderedAttributes":[{"name":"name","type":"string","value":"myMacro"},{"name":"value","type":"string","value":"nothing"}]}]
 
 		);
 	});
@@ -185,7 +185,7 @@ describe("WikiText parser tests", function() {
 	it("should parse comment in pragma area. Comment will be invisible", function() {
 		expect(parse("<!-- comment in pragma area -->\n\\define aMacro()\nnothing\n\\end\n")).toEqual(
 
-			[ { type : 'set', attributes : { name : { type : 'string', value : 'aMacro' }, value : { type : 'string', value : 'nothing' } }, children : [  ], params : [ ], isMacroDefinition : true } ]
+			[{"type":"set","attributes":{"name":{"name":"name","type":"string","value":"aMacro"},"value":{"name":"value","type":"string","value":"nothing"}},"children":[],"params":[],"isMacroDefinition":true,"orderedAttributes":[{"name":"name","type":"string","value":"aMacro"},{"name":"value","type":"string","value":"nothing"}]}]
 
 		);
 	});