Make TOC hideable

[mediawiki.git] / resources / mediawiki / mediawiki.jqueryMsg.js

/**
* Experimental advanced wikitext parser-emitter.
* See: http://www.mediawiki.org/wiki/Extension:UploadWizard/MessageParser for docs
*
* @author neilk@wikimedia.org
* @author mflaschen@wikimedia.org
*/
( function ( mw, $ ) {
        var oldParser,
                slice = Array.prototype.slice,
                parserDefaults = {
                        magic : {
                                'SITENAME' : mw.config.get( 'wgSiteName' )
                        },
                        // This is a whitelist based on, but simpler than, Sanitizer.php.
                        // Self-closing tags are not currently supported.
                        allowedHtmlElements : [
                                'b',
                                'i'
                        ],
                        // Key tag name, value allowed attributes for that tag.
                        // See Sanitizer::setupAttributeWhitelist
                        allowedHtmlCommonAttributes : [
                                // HTML
                                'id',
                                'class',
                                'style',
                                'lang',
                                'dir',
                                'title',

                                // WAI-ARIA
                                'role'
                        ],

                        // Attributes allowed for specific elements.
                        // Key is element name in lower case
                        // Value is array of allowed attributes for that element
                        allowedHtmlAttributesByElement : {},
                        messages : mw.messages,
                        language : mw.language,

                        // Same meaning as in mediawiki.js.
                        //
                        // Only 'text', 'parse', and 'escaped' are supported, and the
                        // actual escaping for 'escaped' is done by other code (generally
                        // through mediawiki.js).
                        //
                        // However, note that this default only
                        // applies to direct calls to jqueryMsg. The default for mediawiki.js itself
                        // is 'text', including when it uses jqueryMsg.
                        format: 'parse'

                };

        /**
         * Wrapper around jQuery append that converts all non-objects to TextNode so append will not
         * convert what it detects as an htmlString to an element.
         *
         * Object elements of children (jQuery, HTMLElement, TextNode, etc.) will be left as is.
         *
         * @param {jQuery} $parent Parent node wrapped by jQuery
         * @param {Object|string|Array} children What to append, with the same possible types as jQuery
         * @return {jQuery} $parent
         */
        function appendWithoutParsing( $parent, children ) {
                var i, len;

                if ( !$.isArray( children ) ) {
                        children = [children];
                }

                for ( i = 0, len = children.length; i < len; i++ ) {
                        if ( typeof children[i] !== 'object' ) {
                                children[i] = document.createTextNode( children[i] );
                        }
                }

                return $parent.append( children );
        }

        /**
         * Decodes the main HTML entities, those encoded by mw.html.escape.
         *
         * @param {string} encode Encoded string
         * @return {string} String with those entities decoded
         */
        function decodePrimaryHtmlEntities( encoded ) {
                return encoded
                        .replace( /&#039;/g, '\'' )
                        .replace( /&quot;/g, '"' )
                        .replace( /&lt;/g, '<' )
                        .replace( /&gt;/g, '>' )
                        .replace( /&amp;/g, '&' );
        }

        /**
         * Given parser options, return a function that parses a key and replacements, returning jQuery object
         * @param {Object} parser options
         * @return {Function} accepting ( String message key, String replacement1, String replacement2 ... ) and returning {jQuery}
         */
        function getFailableParserFn( options ) {
                var parser = new mw.jqueryMsg.parser( options );
                /**
                 * Try to parse a key and optional replacements, returning a jQuery object that may be a tree of jQuery nodes.
                 * If there was an error parsing, return the key and the error message (wrapped in jQuery). This should put the error right into
                 * the interface, without causing the page to halt script execution, and it hopefully should be clearer how to fix it.
                 *
                 * @param {Array} first element is the key, replacements may be in array in 2nd element, or remaining elements.
                 * @return {jQuery}
                 */
                return function ( args ) {
                        var key = args[0],
                                argsArray = $.isArray( args[1] ) ? args[1] : slice.call( args, 1 );
                        try {
                                return parser.parse( key, argsArray );
                        } catch ( e ) {
                                return $( '<span>' ).text( key + ': ' + e.message );
                        }
                };
        }

        mw.jqueryMsg = {};

        /**
         * Class method.
         * Returns a function suitable for use as a global, to construct strings from the message key (and optional replacements).
         * e.g.
         *       window.gM = mediaWiki.parser.getMessageFunction( options );
         *       $( 'p#headline' ).html( gM( 'hello-user', username ) );
         *
         * Like the old gM() function this returns only strings, so it destroys any bindings. If you want to preserve bindings use the
         * jQuery plugin version instead. This is only included for backwards compatibility with gM().
         *
         * @param {Array} parser options
         * @return {Function} function suitable for assigning to window.gM
         */
        mw.jqueryMsg.getMessageFunction = function ( options ) {
                var failableParserFn = getFailableParserFn( options ),
                        format;

                if ( options && options.format !== undefined ) {
                        format = options.format;
                } else {
                        format = parserDefaults.format;
                }

                /**
                 * N.B. replacements are variadic arguments or an array in second parameter. In other words:
                 *    somefunction(a, b, c, d)
                 * is equivalent to
                 *    somefunction(a, [b, c, d])
                 *
                 * @param {string} key Message key.
                 * @param {Array|mixed} replacements Optional variable replacements (variadically or an array).
                 * @return {string} Rendered HTML.
                 */
                return function () {
                        var failableResult = failableParserFn( arguments );
                        if ( format === 'text' || format === 'escaped' ) {
                                return failableResult.text();
                        } else {
                                return failableResult.html();
                        }
                };
        };

        /**
         * Class method.
         * Returns a jQuery plugin which parses the message in the message key, doing replacements optionally, and appends the nodes to
         * the current selector. Bindings to passed-in jquery elements are preserved. Functions become click handlers for [$1 linktext] links.
         * e.g.
         *        $.fn.msg = mediaWiki.parser.getJqueryPlugin( options );
         *        var userlink = $( '<a>' ).click( function () { alert( "hello!!") } );
         *        $( 'p#headline' ).msg( 'hello-user', userlink );
         *
         * @param {Array} parser options
         * @return {Function} function suitable for assigning to jQuery plugin, such as $.fn.msg
         */
        mw.jqueryMsg.getPlugin = function ( options ) {
                var failableParserFn = getFailableParserFn( options );
                /**
                 * N.B. replacements are variadic arguments or an array in second parameter. In other words:
                 *    somefunction(a, b, c, d)
                 * is equivalent to
                 *    somefunction(a, [b, c, d])
                 *
                 * We append to 'this', which in a jQuery plugin context will be the selected elements.
                 * @param {string} key Message key.
                 * @param {Array|mixed} replacements Optional variable replacements (variadically or an array).
                 * @return {jQuery} this
                 */
                return function () {
                        var $target = this.empty();
                        // TODO: Simply appendWithoutParsing( $target, failableParserFn( arguments ).contents() )
                        // or Simply appendWithoutParsing( $target, failableParserFn( arguments ) )
                        $.each( failableParserFn( arguments ).contents(), function ( i, node ) {
                                appendWithoutParsing( $target, node );
                        } );
                        return $target;
                };
        };

        /**
         * The parser itself.
         * Describes an object, whose primary duty is to .parse() message keys.
         * @param {Array} options
         */
        mw.jqueryMsg.parser = function ( options ) {
                this.settings = $.extend( {}, parserDefaults, options );
                this.settings.onlyCurlyBraceTransform = ( this.settings.format === 'text' || this.settings.format === 'escaped' );

                this.emitter = new mw.jqueryMsg.htmlEmitter( this.settings.language, this.settings.magic );
        };

        mw.jqueryMsg.parser.prototype = {
                /**
                 * Cache mapping MediaWiki message keys and the value onlyCurlyBraceTransform, to the AST of the message.
                 *
                 * In most cases, the message is a string so this is identical.
                 * (This is why we would like to move this functionality server-side).
                 *
                 * The two parts of the key are separated by colon.  For example:
                 *
                 * "message-key:true": ast
                 *
                 * if they key is "message-key" and onlyCurlyBraceTransform is true.
                 *
                 * This cache is shared by all instances of mw.jqueryMsg.parser.
                 *
                 * @static
                 */
                astCache: {},

                /**
                 * Where the magic happens.
                 * Parses a message from the key, and swaps in replacements as necessary, wraps in jQuery
                 * If an error is thrown, returns original key, and logs the error
                 * @param {String} key Message key.
                 * @param {Array} replacements Variable replacements for $1, $2... $n
                 * @return {jQuery}
                 */
                parse: function ( key, replacements ) {
                        return this.emitter.emit( this.getAst( key ), replacements );
                },
                /**
                 * Fetch the message string associated with a key, return parsed structure. Memoized.
                 * Note that we pass '[' + key + ']' back for a missing message here.
                 * @param {String} key
                 * @return {String|Array} string of '[key]' if message missing, simple string if possible, array of arrays if needs parsing
                 */
                getAst: function ( key ) {
                        var cacheKey = [key, this.settings.onlyCurlyBraceTransform].join( ':' ), wikiText;

                        if ( this.astCache[ cacheKey ] === undefined ) {
                                wikiText = this.settings.messages.get( key );
                                if ( typeof wikiText !== 'string' ) {
                                        wikiText = '\\[' + key + '\\]';
                                }
                                this.astCache[ cacheKey ] = this.wikiTextToAst( wikiText );
                        }
                        return this.astCache[ cacheKey ];
                },

                /**
                 * Parses the input wikiText into an abstract syntax tree, essentially an s-expression.
                 *
                 * CAVEAT: This does not parse all wikitext. It could be more efficient, but it's pretty good already.
                 * n.b. We want to move this functionality to the server. Nothing here is required to be on the client.
                 *
                 * @param {String} message string wikitext
                 * @throws Error
                 * @return {Mixed} abstract syntax tree
                 */
                wikiTextToAst: function ( input ) {
                        var pos, settings = this.settings, concat = Array.prototype.concat,
                                regularLiteral, regularLiteralWithoutBar, regularLiteralWithoutSpace, regularLiteralWithSquareBrackets,
                                doubleQuote, singleQuote, backslash, anyCharacter, asciiAlphabetLiteral,
                                escapedOrLiteralWithoutSpace, escapedOrLiteralWithoutBar, escapedOrRegularLiteral,
                                whitespace, dollar, digits, htmlDoubleQuoteAttributeValue, htmlSingleQuoteAttributeValue,
                                htmlAttributeEquals, openHtmlStartTag, optionalForwardSlash, openHtmlEndTag, closeHtmlTag,
                                openExtlink, closeExtlink, wikilinkPage, wikilinkContents, openWikilink, closeWikilink, templateName, pipe, colon,
                                templateContents, openTemplate, closeTemplate,
                                nonWhitespaceExpression, paramExpression, expression, curlyBraceTransformExpression, result;

                        // Indicates current position in input as we parse through it.
                        // Shared among all parsing functions below.
                        pos = 0;

                        // =========================================================
                        // parsing combinators - could be a library on its own
                        // =========================================================
                        // Try parsers until one works, if none work return null
                        function choice( ps ) {
                                return function () {
                                        var i, result;
                                        for ( i = 0; i < ps.length; i++ ) {
                                                result = ps[i]();
                                                if ( result !== null ) {
                                                         return result;
                                                }
                                        }
                                        return null;
                                };
                        }
                        // try several ps in a row, all must succeed or return null
                        // this is the only eager one
                        function sequence( ps ) {
                                var i, res,
                                        originalPos = pos,
                                        result = [];
                                for ( i = 0; i < ps.length; i++ ) {
                                        res = ps[i]();
                                        if ( res === null ) {
                                                pos = originalPos;
                                                return null;
                                        }
                                        result.push( res );
                                }
                                return result;
                        }
                        // run the same parser over and over until it fails.
                        // must succeed a minimum of n times or return null
                        function nOrMore( n, p ) {
                                return function () {
                                        var originalPos = pos,
                                                result = [],
                                                parsed = p();
                                        while ( parsed !== null ) {
                                                result.push( parsed );
                                                parsed = p();
                                        }
                                        if ( result.length < n ) {
                                                pos = originalPos;
                                                return null;
                                        }
                                        return result;
                                };
                        }
                        // There is a general pattern -- parse a thing, if that worked, apply transform, otherwise return null.
                        // But using this as a combinator seems to cause problems when combined with nOrMore().
                        // May be some scoping issue
                        function transform( p, fn ) {
                                return function () {
                                        var result = p();
                                        return result === null ? null : fn( result );
                                };
                        }
                        // Helpers -- just make ps out of simpler JS builtin types
                        function makeStringParser( s ) {
                                var len = s.length;
                                return function () {
                                        var result = null;
                                        if ( input.substr( pos, len ) === s ) {
                                                 result = s;
                                                 pos += len;
                                        }
                                        return result;
                                };
                        }

                        /**
                         * Makes a regex parser, given a RegExp object.
                         * The regex being passed in should start with a ^ to anchor it to the start
                         * of the string.
                         *
                         * @param {RegExp} regex anchored regex
                         * @return {Function} function to parse input based on the regex
                         */
                        function makeRegexParser( regex ) {
                                return function () {
                                        var matches = input.substr( pos ).match( regex );
                                        if ( matches === null ) {
                                                return null;
                                        }
                                        pos += matches[0].length;
                                        return matches[0];
                                };
                        }

                        /**
                         *  ===================================================================
                         *  General patterns above this line -- wikitext specific parsers below
                         *  ===================================================================
                         */
                        // Parsing functions follow. All parsing functions work like this:
                        // They don't accept any arguments.
                        // Instead, they just operate non destructively on the string 'input'
                        // As they can consume parts of the string, they advance the shared variable pos,
                        // and return tokens (or whatever else they want to return).
                        // some things are defined as closures and other things as ordinary functions
                        // converting everything to a closure makes it a lot harder to debug... errors pop up
                        // but some debuggers can't tell you exactly where they come from. Also the mutually
                        // recursive functions seem not to work in all browsers then. (Tested IE6-7, Opera, Safari, FF)
                        // This may be because, to save code, memoization was removed

                        regularLiteral = makeRegexParser( /^[^{}\[\]$<\\]/ );
                        regularLiteralWithoutBar = makeRegexParser(/^[^{}\[\]$\\|]/);
                        regularLiteralWithoutSpace = makeRegexParser(/^[^{}\[\]$\s]/);
                        regularLiteralWithSquareBrackets = makeRegexParser( /^[^{}$\\]/ );

                        backslash = makeStringParser( '\\' );
                        doubleQuote = makeStringParser( '"' );
                        singleQuote = makeStringParser( '\'' );
                        anyCharacter = makeRegexParser( /^./ );

                        openHtmlStartTag = makeStringParser( '<' );
                        optionalForwardSlash = makeRegexParser( /^\/?/ );
                        openHtmlEndTag = makeStringParser( '</' );
                        htmlAttributeEquals = makeRegexParser( /^\s*=\s*/ );
                        closeHtmlTag = makeRegexParser( /^\s*>/ );

                        function escapedLiteral() {
                                var result = sequence( [
                                        backslash,
                                        anyCharacter
                                ] );
                                return result === null ? null : result[1];
                        }
                        escapedOrLiteralWithoutSpace = choice( [
                                escapedLiteral,
                                regularLiteralWithoutSpace
                        ] );
                        escapedOrLiteralWithoutBar = choice( [
                                escapedLiteral,
                                regularLiteralWithoutBar
                        ] );
                        escapedOrRegularLiteral = choice( [
                                escapedLiteral,
                                regularLiteral
                        ] );
                        // Used to define "literals" without spaces, in space-delimited situations
                        function literalWithoutSpace() {
                                var result = nOrMore( 1, escapedOrLiteralWithoutSpace )();
                                return result === null ? null : result.join('');
                        }
                        // Used to define "literals" within template parameters. The pipe character is the parameter delimeter, so by default
                        // it is not a literal in the parameter
                        function literalWithoutBar() {
                                var result = nOrMore( 1, escapedOrLiteralWithoutBar )();
                                return result === null ? null : result.join('');
                        }

                        // Used for wikilink page names.  Like literalWithoutBar, but
                        // without allowing escapes.
                        function unescapedLiteralWithoutBar() {
                                var result = nOrMore( 1, regularLiteralWithoutBar )();
                                return result === null ? null : result.join('');
                        }

                        function literal() {
                                var result = nOrMore( 1, escapedOrRegularLiteral )();
                                return result === null ? null : result.join('');
                        }

                        function curlyBraceTransformExpressionLiteral() {
                                var result = nOrMore( 1, regularLiteralWithSquareBrackets )();
                                return result === null ? null : result.join('');
                        }

                        asciiAlphabetLiteral = makeRegexParser( /[A-Za-z]+/ );
                        htmlDoubleQuoteAttributeValue = makeRegexParser( /^[^"]*/ );
                        htmlSingleQuoteAttributeValue = makeRegexParser( /^[^']*/ );

                        whitespace = makeRegexParser( /^\s+/ );
                        dollar = makeStringParser( '$' );
                        digits = makeRegexParser( /^\d+/ );

                        function replacement() {
                                var result = sequence( [
                                        dollar,
                                        digits
                                ] );
                                if ( result === null ) {
                                        return null;
                                }
                                return [ 'REPLACE', parseInt( result[1], 10 ) - 1 ];
                        }
                        openExtlink = makeStringParser( '[' );
                        closeExtlink = makeStringParser( ']' );
                        // this extlink MUST have inner contents, e.g. [foo] not allowed; [foo bar] [foo <i>bar</i>], etc. are allowed
                        function extlink() {
                                var result, parsedResult;
                                result = null;
                                parsedResult = sequence( [
                                        openExtlink,
                                        nonWhitespaceExpression,
                                        whitespace,
                                        nOrMore( 1, expression ),
                                        closeExtlink
                                ] );
                                if ( parsedResult !== null ) {
                                        result = [ 'EXTLINK', parsedResult[1] ];
                                        // TODO (mattflaschen, 2013-03-22): Clean this up if possible.
                                        // It's avoiding CONCAT for single nodes, so they at least doesn't get the htmlEmitter span.
                                        if ( parsedResult[3].length === 1 ) {
                                                result.push( parsedResult[3][0] );
                                        } else {
                                                result.push( ['CONCAT'].concat( parsedResult[3] ) );
                                        }
                                }
                                return result;
                        }
                        // this is the same as the above extlink, except that the url is being passed on as a parameter
                        function extLinkParam() {
                                var result = sequence( [
                                        openExtlink,
                                        dollar,
                                        digits,
                                        whitespace,
                                        expression,
                                        closeExtlink
                                ] );
                                if ( result === null ) {
                                        return null;
                                }
                                return [ 'EXTLINKPARAM', parseInt( result[2], 10 ) - 1, result[4] ];
                        }
                        openWikilink = makeStringParser( '[[' );
                        closeWikilink = makeStringParser( ']]' );
                        pipe = makeStringParser( '|' );

                        function template() {
                                var result = sequence( [
                                        openTemplate,
                                        templateContents,
                                        closeTemplate
                                ] );
                                return result === null ? null : result[1];
                        }

                        wikilinkPage = choice( [
                                unescapedLiteralWithoutBar,
                                template
                        ] );

                        function pipedWikilink() {
                                var result = sequence( [
                                        wikilinkPage,
                                        pipe,
                                        expression
                                ] );
                                return result === null ? null : [ result[0], result[2] ];
                        }

                        wikilinkContents = choice( [
                                pipedWikilink,
                                wikilinkPage // unpiped link
                        ] );

                        function wikilink() {
                                var result, parsedResult, parsedLinkContents;
                                result = null;

                                parsedResult = sequence( [
                                        openWikilink,
                                        wikilinkContents,
                                        closeWikilink
                                ] );
                                if ( parsedResult !== null ) {
                                        parsedLinkContents = parsedResult[1];
                                        result = [ 'WIKILINK' ].concat( parsedLinkContents );
                                }
                                return result;
                        }

                        // TODO: Support data- if appropriate
                        function doubleQuotedHtmlAttributeValue() {
                                var parsedResult = sequence( [
                                        doubleQuote,
                                        htmlDoubleQuoteAttributeValue,
                                        doubleQuote
                                ] );
                                return parsedResult === null ? null : parsedResult[1];
                        }

                        function singleQuotedHtmlAttributeValue() {
                                var parsedResult = sequence( [
                                        singleQuote,
                                        htmlSingleQuoteAttributeValue,
                                        singleQuote
                                ] );
                                return parsedResult === null ? null : parsedResult[1];
                        }

                        function htmlAttribute() {
                                var parsedResult = sequence( [
                                        whitespace,
                                        asciiAlphabetLiteral,
                                        htmlAttributeEquals,
                                        choice( [
                                                doubleQuotedHtmlAttributeValue,
                                                singleQuotedHtmlAttributeValue
                                        ] )
                                ] );
                                return parsedResult === null ? null : [parsedResult[1], parsedResult[3]];
                        }

                        /**
                         * Checks if HTML is allowed
                         *
                         * @param {string} startTagName HTML start tag name
                         * @param {string} endTagName HTML start tag name
                         * @param {Object} attributes array of consecutive key value pairs,
                         *  with index 2 * n being a name and 2 * n + 1 the associated value
                         * @return {boolean} true if this is HTML is allowed, false otherwise
                         */
                        function isAllowedHtml( startTagName, endTagName, attributes ) {
                                var i, len, attributeName;

                                startTagName = startTagName.toLowerCase();
                                endTagName = endTagName.toLowerCase();
                                if ( startTagName !== endTagName || $.inArray( startTagName, settings.allowedHtmlElements ) === -1 ) {
                                        return false;
                                }

                                for ( i = 0, len = attributes.length; i < len; i += 2 ) {
                                        attributeName = attributes[i];
                                        if ( $.inArray( attributeName, settings.allowedHtmlCommonAttributes ) === -1 &&
                                             $.inArray( attributeName, settings.allowedHtmlAttributesByElement[startTagName] || [] ) === -1 ) {
                                                return false;
                                        }
                                }

                                return true;
                        }

                        function htmlAttributes() {
                                var parsedResult = nOrMore( 0, htmlAttribute )();
                                // Un-nest attributes array due to structure of jQueryMsg operations (see emit).
                                return concat.apply( ['HTMLATTRIBUTES'], parsedResult );
                        }

                        // Subset of allowed HTML markup.
                        // Most elements and many attributes allowed on the server are not supported yet.
                        function html() {
                                var result = null, parsedOpenTagResult, parsedHtmlContents,
                                        parsedCloseTagResult, wrappedAttributes, attributes,
                                        startTagName, endTagName, startOpenTagPos, startCloseTagPos,
                                        endOpenTagPos, endCloseTagPos;

                                // Break into three sequence calls.  That should allow accurate reconstruction of the original HTML, and requiring an exact tag name match.
                                // 1. open through closeHtmlTag
                                // 2. expression
                                // 3. openHtmlEnd through close
                                // This will allow recording the positions to reconstruct if HTML is to be treated as text.

                                startOpenTagPos = pos;
                                parsedOpenTagResult = sequence( [
                                        openHtmlStartTag,
                                        asciiAlphabetLiteral,
                                        htmlAttributes,
                                        optionalForwardSlash,
                                        closeHtmlTag
                                ] );

                                if ( parsedOpenTagResult === null ) {
                                        return null;
                                }

                                endOpenTagPos = pos;
                                startTagName = parsedOpenTagResult[1];

                                parsedHtmlContents = nOrMore( 0, expression )();

                                startCloseTagPos = pos;
                                parsedCloseTagResult = sequence( [
                                        openHtmlEndTag,
                                        asciiAlphabetLiteral,
                                        closeHtmlTag
                                ] );

                                if ( parsedCloseTagResult === null ) {
                                        // Closing tag failed.  Return the start tag and contents.
                                        return [ 'CONCAT', input.substring( startOpenTagPos, endOpenTagPos ) ].concat( parsedHtmlContents );
                                }

                                endCloseTagPos = pos;
                                endTagName = parsedCloseTagResult[1];
                                wrappedAttributes = parsedOpenTagResult[2];
                                attributes = wrappedAttributes.slice( 1 );
                                if ( isAllowedHtml( startTagName, endTagName, attributes) ) {
                                        result = [ 'HTMLELEMENT', startTagName, wrappedAttributes ].concat( parsedHtmlContents );
                                } else {
                                        // HTML is not allowed, so contents will remain how
                                        // it was, while HTML markup at this level will be
                                        // treated as text
                                        // E.g. assuming script tags are not allowed:
                                        //
                                        // <script>[[Foo|bar]]</script>
                                        //
                                        // results in '&lt;script&gt;' and '&lt;/script&gt;'
                                        // (not treated as an HTML tag), surrounding a fully
                                        // parsed HTML link.
                                        //
                                        // Concatenate everything from the tag, flattening the contents.
                                        result = [ 'CONCAT', input.substring( startOpenTagPos, endOpenTagPos ) ].concat( parsedHtmlContents, input.substring( startCloseTagPos, endCloseTagPos ) );
                                }

                                return result;
                        }

                        templateName = transform(
                                // see $wgLegalTitleChars
                                // not allowing : due to the need to catch "PLURAL:$1"
                                makeRegexParser( /^[ !"$&'()*,.\/0-9;=?@A-Z\^_`a-z~\x80-\xFF+\-]+/ ),
                                function ( result ) { return result.toString(); }
                        );
                        function templateParam() {
                                var expr, result;
                                result = sequence( [
                                        pipe,
                                        nOrMore( 0, paramExpression )
                                ] );
                                if ( result === null ) {
                                        return null;
                                }
                                expr = result[1];
                                // use a CONCAT operator if there are multiple nodes, otherwise return the first node, raw.
                                return expr.length > 1 ? [ 'CONCAT' ].concat( expr ) : expr[0];
                        }

                        function templateWithReplacement() {
                                var result = sequence( [
                                        templateName,
                                        colon,
                                        replacement
                                ] );
                                return result === null ? null : [ result[0], result[2] ];
                        }
                        function templateWithOutReplacement() {
                                var result = sequence( [
                                        templateName,
                                        colon,
                                        paramExpression
                                ] );
                                return result === null ? null : [ result[0], result[2] ];
                        }
                        colon = makeStringParser(':');
                        templateContents = choice( [
                                function () {
                                        var res = sequence( [
                                                // templates can have placeholders for dynamic replacement eg: {{PLURAL:$1|one car|$1 cars}}
                                                // or no placeholders eg: {{GRAMMAR:genitive|{{SITENAME}}}
                                                choice( [ templateWithReplacement, templateWithOutReplacement ] ),
                                                nOrMore( 0, templateParam )
                                        ] );
                                        return res === null ? null : res[0].concat( res[1] );
                                },
                                function () {
                                        var res = sequence( [
                                                templateName,
                                                nOrMore( 0, templateParam )
                                        ] );
                                        if ( res === null ) {
                                                return null;
                                        }
                                        return [ res[0] ].concat( res[1] );
                                }
                        ] );
                        openTemplate = makeStringParser('{{');
                        closeTemplate = makeStringParser('}}');
                        nonWhitespaceExpression = choice( [
                                template,
                                wikilink,
                                extLinkParam,
                                extlink,
                                replacement,
                                literalWithoutSpace
                        ] );
                        paramExpression = choice( [
                                template,
                                wikilink,
                                extLinkParam,
                                extlink,
                                replacement,
                                literalWithoutBar
                        ] );

                        expression = choice( [
                                template,
                                wikilink,
                                extLinkParam,
                                extlink,
                                replacement,
                                html,
                                literal
                        ] );

                        // Used when only {{-transformation is wanted, for 'text'
                        // or 'escaped' formats
                        curlyBraceTransformExpression = choice( [
                                template,
                                replacement,
                                curlyBraceTransformExpressionLiteral
                        ] );


                        /**
                         * Starts the parse
                         *
                         * @param {Function} rootExpression root parse function
                         */
                        function start( rootExpression ) {
                                var result = nOrMore( 0, rootExpression )();
                                if ( result === null ) {
                                        return null;
                                }
                                return [ 'CONCAT' ].concat( result );
                        }
                        // everything above this point is supposed to be stateless/static, but
                        // I am deferring the work of turning it into prototypes & objects. It's quite fast enough
                        // finally let's do some actual work...

                        // If you add another possible rootExpression, you must update the astCache key scheme.
                        result = start( this.settings.onlyCurlyBraceTransform ? curlyBraceTransformExpression : expression );

                        /*
                         * For success, the p must have gotten to the end of the input
                         * and returned a non-null.
                         * n.b. This is part of language infrastructure, so we do not throw an internationalizable message.
                         */
                        if ( result === null || pos !== input.length ) {
                                throw new Error( 'Parse error at position ' + pos.toString() + ' in input: ' + input );
                        }
                        return result;
                }

        };
        /**
         * htmlEmitter - object which primarily exists to emit HTML from parser ASTs
         */
        mw.jqueryMsg.htmlEmitter = function ( language, magic ) {
                this.language = language;
                var jmsg = this;
                $.each( magic, function ( key, val ) {
                        jmsg[ key.toLowerCase() ] = function () {
                                return val;
                        };
                } );
                /**
                 * (We put this method definition here, and not in prototype, to make sure it's not overwritten by any magic.)
                 * Walk entire node structure, applying replacements and template functions when appropriate
                 * @param {Mixed} abstract syntax tree (top node or subnode)
                 * @param {Array} replacements for $1, $2, ... $n
                 * @return {Mixed} single-string node or array of nodes suitable for jQuery appending
                 */
                this.emit = function ( node, replacements ) {
                        var ret, subnodes, operation,
                                jmsg = this;
                        switch ( typeof node ) {
                                case 'string':
                                case 'number':
                                        ret = node;
                                        break;
                                // typeof returns object for arrays
                                case 'object':
                                        // node is an array of nodes
                                        subnodes = $.map( node.slice( 1 ), function ( n ) {
                                                return jmsg.emit( n, replacements );
                                        } );
                                        operation = node[0].toLowerCase();
                                        if ( typeof jmsg[operation] === 'function' ) {
                                                ret = jmsg[ operation ]( subnodes, replacements );
                                        } else {
                                                throw new Error( 'Unknown operation "' + operation + '"' );
                                        }
                                        break;
                                case 'undefined':
                                        // Parsing the empty string (as an entire expression, or as a paramExpression in a template) results in undefined
                                        // Perhaps a more clever parser can detect this, and return the empty string? Or is that useful information?
                                        // The logical thing is probably to return the empty string here when we encounter undefined.
                                        ret = '';
                                        break;
                                default:
                                        throw new Error( 'Unexpected type in AST: ' + typeof node );
                        }
                        return ret;
                };
        };
        // For everything in input that follows double-open-curly braces, there should be an equivalent parser
        // function. For instance {{PLURAL ... }} will be processed by 'plural'.
        // If you have 'magic words' then configure the parser to have them upon creation.
        //
        // An emitter method takes the parent node, the array of subnodes and the array of replacements (the values that $1, $2... should translate to).
        // Note: all such functions must be pure, with the exception of referring to other pure functions via this.language (convertPlural and so on)
        mw.jqueryMsg.htmlEmitter.prototype = {
                /**
                 * Parsing has been applied depth-first we can assume that all nodes here are single nodes
                 * Must return a single node to parents -- a jQuery with synthetic span
                 * However, unwrap any other synthetic spans in our children and pass them upwards
                 * @param {Array} nodes - mixed, some single nodes, some arrays of nodes
                 * @return {jQuery}
                 */
                concat: function ( nodes ) {
                        var $span = $( '<span>' ).addClass( 'mediaWiki_htmlEmitter' );
                        $.each( nodes, function ( i, node ) {
                                if ( node instanceof jQuery && node.hasClass( 'mediaWiki_htmlEmitter' ) ) {
                                        $.each( node.contents(), function ( j, childNode ) {
                                                appendWithoutParsing( $span, childNode );
                                        } );
                                } else {
                                        // Let jQuery append nodes, arrays of nodes and jQuery objects
                                        // other things (strings, numbers, ..) are appended as text nodes (not as HTML strings)
                                        appendWithoutParsing( $span, node );
                                }
                        } );
                        return $span;
                },

                /**
                 * Return escaped replacement of correct index, or string if unavailable.
                 * Note that we expect the parsed parameter to be zero-based. i.e. $1 should have become [ 0 ].
                 * if the specified parameter is not found return the same string
                 * (e.g. "$99" -> parameter 98 -> not found -> return "$99" )
                 * TODO: Throw error if nodes.length > 1 ?
                 * @param {Array} of one element, integer, n >= 0
                 * @return {String} replacement
                 */
                replace: function ( nodes, replacements ) {
                        var index = parseInt( nodes[0], 10 );

                        if ( index < replacements.length ) {
                                return replacements[index];
                        } else {
                                // index not found, fallback to displaying variable
                                return '$' + ( index + 1 );
                        }
                },

                /**
                 * Transform wiki-link
                 *
                 * TODO:
                 * It only handles basic cases, either no pipe, or a pipe with an explicit
                 * anchor.
                 *
                 * It does not attempt to handle features like the pipe trick.
                 * However, the pipe trick should usually not be present in wikitext retrieved
                 * from the server, since the replacement is done at save time.
                 * It may, though, if the wikitext appears in extension-controlled content.
                 *
                 * @param nodes
                 */
                wikilink: function ( nodes ) {
                        var page, anchor, url;

                        page = nodes[0];
                        url = mw.util.wikiGetlink( page );

                        // [[Some Page]] or [[Namespace:Some Page]]
                        if ( nodes.length === 1 ) {
                                anchor = page;
                        }

                        /*
                         * [[Some Page|anchor text]] or
                         * [[Namespace:Some Page|anchor]
                         */
                        else {
                                anchor = nodes[1];
                        }

                        return $( '<a />' ).attr( {
                                title: page,
                                href: url
                        } ).text( anchor );
                },

                /**
                 * Converts array of HTML element key value pairs to object
                 *
                 * @param {Array} nodes array of consecutive key value pairs, with index 2 * n being a name and 2 * n + 1 the associated value
                 * @return {Object} object mapping attribute name to attribute value
                 */
                htmlattributes: function ( nodes ) {
                        var i, len, mapping = {};
                        for ( i = 0, len = nodes.length; i < len; i += 2 ) {
                                mapping[nodes[i]] = decodePrimaryHtmlEntities( nodes[i + 1] );
                        }
                        return mapping;
                },

                /**
                 * Handles an (already-validated) HTML element.
                 *
                 * @param {Array} nodes nodes to process when creating element
                 * @return {jQuery|Array} jQuery node for valid HTML or array for disallowed element
                 */
                htmlelement: function ( nodes ) {
                        var tagName, attributes, contents, $element;

                        tagName = nodes.shift();
                        attributes = nodes.shift();
                        contents = nodes;
                        $element = $( document.createElement( tagName ) ).attr( attributes );
                        return appendWithoutParsing( $element, contents );
                },

                /**
                 * Transform parsed structure into external link
                 * If the href is a jQuery object, treat it as "enclosing" the link text.
                 *              ... function, treat it as the click handler
                 *              ... string, treat it as a URI
                 * TODO: throw an error if nodes.length > 2 ?
                 * @param {Array} of two elements, {jQuery|Function|String} and {String}
                 * @return {jQuery}
                 */
                extlink: function ( nodes ) {
                        var $el,
                                arg = nodes[0],
                                contents = nodes[1];
                        if ( arg instanceof jQuery ) {
                                $el = arg;
                        } else {
                                $el = $( '<a>' );
                                if ( typeof arg === 'function' ) {
                                        $el.click( arg ).attr( 'href', '#' );
                                } else {
                                        $el.attr( 'href', arg.toString() );
                                }
                        }
                        return appendWithoutParsing( $el, contents );
                },

                /**
                 * This is basically use a combination of replace + external link (link with parameter
                 * as url), but we don't want to run the regular replace here-on: inserting a
                 * url as href-attribute of a link will automatically escape it already, so
                 * we don't want replace to (manually) escape it as well.
                 * TODO throw error if nodes.length > 1 ?
                 * @param {Array} of one element, integer, n >= 0
                 * @return {String} replacement
                 */
                extlinkparam: function ( nodes, replacements ) {
                        var replacement,
                                index = parseInt( nodes[0], 10 );
                        if ( index < replacements.length) {
                                replacement = replacements[index];
                        } else {
                                replacement = '$' + ( index + 1 );
                        }
                        return this.extlink( [ replacement, nodes[1] ] );
                },

                /**
                 * Transform parsed structure into pluralization
                 * n.b. The first node may be a non-integer (for instance, a string representing an Arabic number).
                 * So convert it back with the current language's convertNumber.
                 * @param {Array} of nodes, [ {String|Number}, {String}, {String} ... ]
                 * @return {String} selected pluralized form according to current language
                 */
                plural: function ( nodes ) {
                        var forms, count;
                        count = parseFloat( this.language.convertNumber( nodes[0], true ) );
                        forms = nodes.slice(1);
                        return forms.length ? this.language.convertPlural( count, forms ) : '';
                },

                /**
                 * Transform parsed structure according to gender.
                 * Usage {{gender:[ gender | mw.user object ] | masculine form|feminine form|neutral form}}.
                 * The first node is either a string, which can be "male" or "female",
                 * or a User object (not a username).
                 *
                 * @param {Array} of nodes, [ {String|mw.User}, {String}, {String}, {String} ]
                 * @return {String} selected gender form according to current language
                 */
                gender: function ( nodes ) {
                        var gender, forms;

                        if  ( nodes[0] && nodes[0].options instanceof mw.Map ) {
                                gender = nodes[0].options.get( 'gender' );
                        } else {
                                gender = nodes[0];
                        }

                        forms = nodes.slice( 1 );

                        return this.language.gender( gender, forms );
                },

                /**
                 * Transform parsed structure into grammar conversion.
                 * Invoked by putting {{grammar:form|word}} in a message
                 * @param {Array} of nodes [{Grammar case eg: genitive}, {String word}]
                 * @return {String} selected grammatical form according to current language
                 */
                grammar: function ( nodes ) {
                        var form = nodes[0],
                                word = nodes[1];
                        return word && form && this.language.convertGrammar( word, form );
                },

                /**
                 * Tranform parsed structure into a int: (interface language) message include
                 * Invoked by putting {{int:othermessage}} into a message
                 * @param {Array} of nodes
                 * @return {string} Other message
                 */
                int: function ( nodes ) {
                        return mw.jqueryMsg.getMessageFunction()( nodes[0].toLowerCase() );
                },

                /**
                 * Takes an unformatted number (arab, no group separators and . as decimal separator)
                 * and outputs it in the localized digit script and formatted with decimal
                 * separator, according to the current language
                 * @param {Array} of nodes
                 * @return {Number|String} formatted number
                 */
                formatnum: function ( nodes ) {
                        var isInteger = ( nodes[1] && nodes[1] === 'R' ) ? true : false,
                                number = nodes[0];

                        return this.language.convertNumber( number, isInteger );
                }
        };
        // Deprecated! don't rely on gM existing.
        // The window.gM ought not to be required - or if required, not required here.
        // But moving it to extensions breaks it (?!)
        // Need to fix plugin so it could do attributes as well, then will be okay to remove this.
        window.gM = mw.jqueryMsg.getMessageFunction();
        $.fn.msg = mw.jqueryMsg.getPlugin();

        // Replace the default message parser with jqueryMsg
        oldParser = mw.Message.prototype.parser;
        mw.Message.prototype.parser = function () {
                var messageFunction;

                // TODO: should we cache the message function so we don't create a new one every time? Benchmark this maybe?
                // Caching is somewhat problematic, because we do need different message functions for different maps, so
                // we'd have to cache the parser as a member of this.map, which sounds a bit ugly.
                // Do not use mw.jqueryMsg unless required
                if ( this.format === 'plain' || !/\{\{|[\[<>]/.test(this.map.get( this.key ) ) ) {
                        // Fall back to mw.msg's simple parser
                        return oldParser.apply( this );
                }

                messageFunction = mw.jqueryMsg.getMessageFunction( {
                        'messages': this.map,
                        // For format 'escaped', escaping part is handled by mediawiki.js
                        'format': this.format
                } );
                return messageFunction( this.key, this.parameters );
        };

}( mediaWiki, jQuery ) );