Re-establish caching of results of parsing a tiddler

I switched this optimisation off back in
ed35d91be6, in October 2013, as part of a
big refactoring of the parsing and widget mechanism. I’ve been meaning
to switch it back on for some time.

My rough measurements suggest that this optimisation can reduce
rendering time by 5-10%.

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

@@ -78,10 +78,13 @@ exports.parse = function() {
 	}
 	// Save the macro definition
 	return [{
-		type: "macrodef",
-		name: this.match[1],
-		params: params,
-		text: text
+		type: "set",
+		attributes: {
+			name: {type: "string", value: this.match[1]},
+			value: {type: "string", value: text}
+		},
+		children: [],
+		params: params
 	}];
 };
 

core/modules/parsers/wikiparser/wikiparser.js

@@ -48,12 +48,13 @@ var WikiParser = function(type,text,options) {
 	this.blockRules = this.instantiateRules(this.blockRuleClasses,"block",0);
 	this.inlineRules = this.instantiateRules(this.inlineRuleClasses,"inline",0);
 	// Parse any pragmas
-	this.tree = this.parsePragmas();
+	this.tree = [];
+	var topBranch = this.parsePragmas();
 	// Parse the text into inline runs or blocks
 	if(options.parseAsInline) {
-		this.tree.push.apply(this.tree,this.parseInlineRun());
+		topBranch.push.apply(topBranch,this.parseInlineRun());
 	} else {
-		this.tree.push.apply(this.tree,this.parseBlocks());
+		topBranch.push.apply(topBranch,this.parseBlocks());
 	}
 	// Return the parse tree
 };
@@ -122,7 +123,7 @@ WikiParser.prototype.findNextMatch = function(rules,startPos) {
 Parse any pragmas at the beginning of a block of parse text
 */
 WikiParser.prototype.parsePragmas = function() {
-	var tree = [];
+	var currentTreeBranch = this.tree;
 	while(true) {
 		// Skip whitespace
 		this.skipWhitespace();
@@ -137,9 +138,15 @@ WikiParser.prototype.parsePragmas = function() {
 			break;
 		}
 		// Process the pragma rule
-		tree.push.apply(tree,nextMatch.rule.parse());
+		var subTree = nextMatch.rule.parse();
+		if(subTree.length > 0) {
+			// Quick hack; we only cope with a single parse tree node being returned, which is true at the moment
+			currentTreeBranch.push.apply(currentTreeBranch,subTree);
+			subTree[0].children = [];
+			currentTreeBranch = subTree[0].children;
+		}
 	}
-	return tree;
+	return currentTreeBranch;
 };
 
 /*

core/modules/wiki.js

@@ -705,22 +705,18 @@ exports.clearGlobalCache = function() {
 
 // Return the named cache object for a tiddler. If the cache doesn't exist then the initializer function is invoked to create it
 exports.getCacheForTiddler = function(title,cacheName,initializer) {
-
-// Temporarily disable caching so that tweakParseTreeNode() works
-return initializer();
-
-//	this.caches = this.caches || Object.create(null);
-//	var caches = this.caches[title];
-//	if(caches && caches[cacheName]) {
-//		return caches[cacheName];
-//	} else {
-//		if(!caches) {
-//			caches = Object.create(null);
-//			this.caches[title] = caches;
-//		}
-//		caches[cacheName] = initializer();
-//		return caches[cacheName];
-//	}
+	this.caches = this.caches || Object.create(null);
+	var caches = this.caches[title];
+	if(caches && caches[cacheName]) {
+		return caches[cacheName];
+	} else {
+		if(!caches) {
+			caches = Object.create(null);
+			this.caches[title] = caches;
+		}
+		caches[cacheName] = initializer();
+		return caches[cacheName];
+	}
 };
 
 // Clear all caches associated with a particular tiddler
@@ -753,7 +749,7 @@ Options include:
 	parseAsInline: if true, the text of the tiddler will be parsed as an inline run
 	_canonical_uri: optional string of the canonical URI of this content
 */
-exports.old_parseText = function(type,text,options) {
+exports.parseText = function(type,text,options) {
 	options = options || {};
 	// Select a parser
 	var Parser = $tw.Wiki.parsers[type];
@@ -777,7 +773,7 @@ exports.old_parseText = function(type,text,options) {
 /*
 Parse a tiddler according to its MIME type
 */
-exports.old_parseTiddler = function(title,options) {
+exports.parseTiddler = function(title,options) {
 	options = $tw.utils.extend({},options);
 	var cacheType = options.parseAsInline ? "newInlineParseTree" : "newBlockParseTree",
 		tiddler = this.getTiddler(title),
@@ -786,44 +782,10 @@ exports.old_parseTiddler = function(title,options) {
 			if(tiddler.hasField("_canonical_uri")) {
 				options._canonical_uri = tiddler.fields._canonical_uri;
 			}
-			return self.old_parseText(tiddler.fields.type,tiddler.fields.text,options);
+			return self.parseText(tiddler.fields.type,tiddler.fields.text,options);
 		}) : null;
 };
 
-var tweakMacroDefinition = function(nodeList) {
-	if(nodeList && nodeList[0] && nodeList[0].type === "macrodef") {
-		nodeList[0].type = "set";
-		nodeList[0].attributes = {
-			name: {type: "string", value: nodeList[0].name},
-			value: {type: "string", value: nodeList[0].text}
-		};
-		nodeList[0].children = nodeList.slice(1);
-		nodeList.splice(1,nodeList.length-1);
-		tweakMacroDefinition(nodeList[0].children);
-	}
-};
-
-var tweakParser = function(parser) {
-	// Move any macro definitions to contain the body tree
-	tweakMacroDefinition(parser.tree);
-};
-
-exports.parseText = function(type,text,options) {
-	var parser = this.old_parseText(type,text,options);
-	if(parser) {
-		tweakParser(parser);
-	}
-	return parser;
-};
-
-exports.parseTiddler = function(title,options) {
-	var parser = this.old_parseTiddler(title,options);
-	if(parser) {
-		tweakParser(parser);
-	}
-	return parser;
-};
-
 exports.parseTextReference = function(title,field,index,options) {
 	var tiddler,text;
 	if(options.subTiddler) {