The source code

    /*!
     * Ext JS Library 3.2.1
     * Copyright(c) 2006-2010 Ext JS, Inc.
     * licensing@extjs.com
     * http://www.extjs.com/license
     */
    /**
     * @class Ext.Template
     */
    Ext.apply(Ext.Template.prototype, {
        /**
         * @cfg {Boolean} disableFormats Specify true to disable format
         * functions in the template. If the template does not contain
         * {@link Ext.util.Format format functions}, setting disableFormats
         * to true will reduce {@link #apply} time. Defaults to false.
         *
    var t = new Ext.Template(
        '<div name="{id}">',
            '<span class="{cls}">{name} {value}</span>',
        '</div>',
        {
            compiled: true,      // {@link #compile} immediately
            disableFormats: true // reduce {@link #apply} time since no formatting
        }
    );
         *
         * For a list of available format functions, see {@link Ext.util.Format}.
         */
        disableFormats : false,
        /**
         * See {@link #disableFormats}.
         * @type Boolean
         * @property disableFormats
         */

        /**
         * The regular expression used to match template variables
         * @type RegExp
         * @property
         * @hide repeat doc
         */
        re : /\{([\w-]+)(?:\:([\w\.]*)(?:\((.*?)?\))?)?\}/g,
        argsRe : /^\s*['"](.*)["']\s*$/,
        compileARe : /\\/g,
        compileBRe : /(\r\n|\n)/g,
        compileCRe : /'/g,

        /**
         * Returns an HTML fragment of this template with the specified values applied.
         * @param {Object/Array} values The template values. Can be an array if your params are numeric (i.e. {0}) or an object (i.e. {foo: 'bar'})
         * @return {String} The HTML fragment
         * @hide repeat doc
         */
        applyTemplate : function(values){
            var me = this,
                useF = me.disableFormats !== true,
                fm = Ext.util.Format,
                tpl = me;

            if(me.compiled){
                return me.compiled(values);
            }
            function fn(m, name, format, args){
                if (format && useF) {
                    if (format.substr(0, 5) == "this.") {
                        return tpl.call(format.substr(5), values[name], values);
                    } else {
                        if (args) {
                            // quoted values are required for strings in compiled templates,
                            // but for non compiled we need to strip them
                            // quoted reversed for jsmin
                            var re = me.argsRe;
                            args = args.split(',');
                            for(var i = 0, len = args.length; i < len; i++){
                                args[i] = args[i].replace(re, "$1");
                            }
                            args = [values[name]].concat(args);
                        } else {
                            args = [values[name]];
                        }
                        return fm[format].apply(fm, args);
                    }
                } else {
                    return values[name] !== undefined ? values[name] : "";
                }
            }
            return me.html.replace(me.re, fn);
        },

        /**
         * Compiles the template into an internal function, eliminating the RegEx overhead.
         * @return {Ext.Template} this
         * @hide repeat doc
         */
        compile : function(){
            var me = this,
                fm = Ext.util.Format,
                useF = me.disableFormats !== true,
                sep = Ext.isGecko ? "+" : ",",
                body;

            function fn(m, name, format, args){
                if(format && useF){
                    args = args ? ',' + args : "";
                    if(format.substr(0, 5) != "this."){
                        format = "fm." + format + '(';
                    }else{
                        format = 'this.call("'+ format.substr(5) + '", ';
                        args = ", values";
                    }
                }else{
                    args= ''; format = "(values['" + name + "'] == undefined ? '' : ";
                }
                return "'"+ sep + format + "values['" + name + "']" + args + ")"+sep+"'";
            }

            // branched to use + in gecko and [].join() in others
            if(Ext.isGecko){
                body = "this.compiled = function(values){ return '" +
                       me.html.replace(me.compileARe, '\\\\').replace(me.compileBRe, '\\n').replace(me.compileCRe, "\\'").replace(me.re, fn) +
                        "';};";
            }else{
                body = ["this.compiled = function(values){ return ['"];
                body.push(me.html.replace(me.compileARe, '\\\\').replace(me.compileBRe, '\\n').replace(me.compileCRe, "\\'").replace(me.re, fn));
                body.push("'].join('');};");
                body = body.join('');
            }
            eval(body);
            return me;
        },

        // private function used to call members
        call : function(fnName, value, allValues){
            return this[fnName](value, allValues);
        }
    });
    Ext.Template.prototype.apply = Ext.Template.prototype.applyTemplate;