Add "rules" pragma for specifiying parser rules to be used for a tiddler

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

@@ -0,0 +1,62 @@
+/*\
+title: $:/core/modules/parsers/wikiparser/rules/rules.js
+type: application/javascript
+module-type: wikirule
+
+Wiki pragma rule for rules specifications
+
+```
+\rules except ruleone ruletwo rulethree
+\rules only ruleone ruletwo rulethree
+```
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.name = "rules";
+exports.types = {pragma: true};
+
+/*
+Instantiate parse rule
+*/
+exports.init = function(parser) {
+	this.parser = parser;
+	// Regexp to match
+	this.matchRegExp = /^\\rules[^\S\n]/mg;
+};
+
+/*
+Parse the most recent match
+*/
+exports.parse = function() {
+	// Move past the pragma invocation
+	this.parser.pos = this.matchRegExp.lastIndex;
+	// Parse whitespace delimited tokens terminated by a line break
+	var reMatch = /[^\S\n]*(\S+)|(\r?\n)/mg,
+		tokens = [];
+	reMatch.lastIndex = this.parser.pos;
+	var match = reMatch.exec(this.parser.source);
+	while(match && match.index === this.parser.pos) {
+		this.parser.pos = reMatch.lastIndex;
+		// Exit if we've got the line break
+		if(match[2]) {
+			break;
+		}
+		// Process the token
+		if(match[1]) {
+			tokens.push(match[1]);
+		}
+		// Match the next token
+		match = reMatch.exec(this.parser.source);
+	}
+	// Process the tokens
+	if(tokens.length > 0) {
+		this.parser.amendRules(tokens[0],tokens.slice(1));
+	}
+};
+
+})();

core/modules/parsers/wikiparser/wikiparser.js

@@ -39,11 +39,11 @@ var WikiParser = function(vocabulary,type,text,options) {
 	this.macroDefinitions = {}; // Hash map of macro definitions
 	// Instantiate the pragma parse rules
 	this.pragmaRules = this.instantiateRules(this.vocabulary.pragmaRuleClasses,"pragma",0);
+	// Instantiate the parser block and inline rules
+	this.blockRules = this.instantiateRules(this.vocabulary.blockRuleClasses,"block",0);
+	this.inlineRules = this.instantiateRules(this.vocabulary.inlineRuleClasses,"inline",0);
 	// Parse any pragmas
 	this.parsePragmas();
-	// Instantiate the parser block and inline rules
-	this.blockRules = this.instantiateRules(this.vocabulary.blockRuleClasses,"block",this.pos);
-	this.inlineRules = this.instantiateRules(this.vocabulary.inlineRuleClasses,"inline",this.pos);
 	// Parse the text into inline runs or blocks
 	if(options.parseAsInline) {
 		this.tree = this.parseInlineRun();
@@ -305,6 +305,40 @@ WikiParser.prototype.parseClasses = function() {
 	return classNames;
 };
 
+/*
+Amend the rules used by this instance of the parser
+	type: `only` keeps just the named rules, `except` keeps all but the named rules
+	names: array of rule names
+*/
+WikiParser.prototype.amendRules = function(type,names) {
+	names = names || [];
+	// Define the filter function
+	var keepFilter;
+	if(type === "only") {
+		keepFilter = function(name) {
+			return names.indexOf(name) !== -1;
+		};
+	} else if(type === "except") {
+		keepFilter = function(name) {
+			return names.indexOf(name) === -1;
+		};
+	} else {
+		return;
+	}
+	// Define a function to process each of our rule arrays
+	var processRuleArray = function(ruleArray) {
+		for(var t=ruleArray.length-1; t>=0; t--) {
+			if(!keepFilter(ruleArray[t].rule.name)) {
+				ruleArray.splice(t,1);
+			}
+		}
+	};
+	// Process each rule array
+	processRuleArray(this.pragmaRules);
+	processRuleArray(this.blockRules);
+	processRuleArray(this.inlineRules);
+}
+
 exports.WikiParser = WikiParser;
 
 })();