    // @tag core
    /**
     * This class compiles the XTemplate syntax into a function object. The function is used
     * like so:
     *
     *      function (out, values, parent, xindex, xcount) {
     *          // out is the output array to store results
     *          // values, parent, xindex and xcount have their historical meaning
     *      }
     *
     * @markdown
     * @private
     */
    Ext.define('Ext.XTemplateCompiler', {
        extend: 'Ext.XTemplateParser',

        // Chrome really likes "new Function" to realize the code block (as in it is
        // 2x-3x faster to call it than using eval), but Firefox chokes on it badly.
        // IE and Opera are also fine with the "new Function" technique.
        useEval: Ext.isGecko,

        // See http://jsperf.com/nige-array-append for quickest way to append to an array of unknown length
        // (Due to arbitrary code execution inside a template, we cannot easily track the length in  var)
        // On IE6 to 8, myArray[myArray.length]='foo' is better. On other browsers myArray.push('foo') is better.
        useIndex: Ext.isIE8m,

        useFormat: true,

        propNameRe: /^[\w\d\$]*$/,

        compile: function (tpl) {
            var me = this,
                code = me.generate(tpl);

            // When using "new Function", we have to pass our "Ext" variable to it in order to
            // support sandboxing. If we did not, the generated function would use the global
            // "Ext", not the "Ext" from our sandbox (scope chain).
            //
            return me.useEval ? me.evalTpl(code) : (new Function('Ext', code))(Ext);
        },

        generate: function (tpl) {
            var me = this,
                // note: Ext here is properly sandboxed
                definitions = 'var fm=Ext.util.Format,ts=Object.prototype.toString;',
                code;

            // Track how many levels we use, so that we only "var" each level's variables once
            me.maxLevel = 0;

            me.body = [
                'var c0=values, a0=' + me.createArrayTest(0) + ', p0=parent, n0=xcount, i0=xindex, k0, v;\n'
            ];
            if (me.definitions) {
                if (typeof me.definitions === 'string') {
                    me.definitions = [me.definitions, definitions ];
                } else {
                    me.definitions.push(definitions);
                }
            } else {
                me.definitions = [ definitions ];
            }
            me.switches = [];

            me.parse(tpl);

            me.definitions.push(
                (me.useEval ? '$=' : 'return') + ' function (' + me.fnArgs + ') {',
                    me.body.join(''),
                '}'
            );

            code = me.definitions.join('\n');

            // Free up the arrays.
            me.definitions.length = me.body.length = me.switches.length = 0;
            delete me.definitions;
            delete me.body;
            delete me.switches;

            return code;
        },

        //-----------------------------------
        // XTemplateParser callouts

        doText: function (text) {
            var me = this,
                out = me.body;

            text = text.replace(me.aposRe, "\\'").replace(me.newLineRe, '\\n');
            if (me.useIndex) {
                out.push('out[out.length]=\'', text, '\'\n');
            } else {
                out.push('out.push(\'', text, '\')\n');
            }
        },

        doExpr: function (expr) {
            var out = this.body;
            out.push('if ((v=' + expr + ') != null) out');

            // Coerce value to string using concatenation of an empty string literal.
            // See http://jsperf.com/tostringvscoercion/5
            if (this.useIndex) {
                 out.push('[out.length]=v+\'\'\n');
            } else {
                 out.push('.push(v+\'\')\n');
            }
        },

        doTag: function (tag) {
            var expr = this.parseTag(tag);
            if (expr) {
                this.doExpr(expr);
            } else {
                // if we cannot match on tagRe handle as plain text
                this.doText('{' + tag + '}');
            }
        },

        doElse: function () {
            this.body.push('} else {\n');
        },

        doEval: function (text) {
            this.body.push(text, '\n');
        },

        doIf: function (action, actions) {
            var me = this;

            // If it's just a propName, use it directly in the if
            if (action === '.') {
                me.body.push('if (values) {\n');
            } else if (me.propNameRe.test(action)) {
                me.body.push('if (', me.parseTag(action), ') {\n');
            }
            // Otherwise, it must be an expression, and needs to be returned from an fn which uses with(values)
            else {
                me.body.push('if (', me.addFn(action), me.callFn, ') {\n');
            }
            if (actions.exec) {
                me.doExec(actions.exec);
            }
        },

        doElseIf: function (action, actions) {
            var me = this;

            // If it's just a propName, use it directly in the else if
            if (action === '.') {
                me.body.push('else if (values) {\n');
            } else if (me.propNameRe.test(action)) {
                me.body.push('} else if (', me.parseTag(action), ') {\n');
            }
            // Otherwise, it must be an expression, and needs to be returned from an fn which uses with(values)
            else {
                me.body.push('} else if (', me.addFn(action), me.callFn, ') {\n');
            }
            if (actions.exec) {
                me.doExec(actions.exec);
            }
        },

        doSwitch: function (action) {
            var me = this;

            // If it's just a propName, use it directly in the switch
            if (action === '.') {
                me.body.push('switch (values) {\n');
            } else if (me.propNameRe.test(action)) {
                me.body.push('switch (', me.parseTag(action), ') {\n');
            }
            // Otherwise, it must be an expression, and needs to be returned from an fn which uses with(values)
            else {
                me.body.push('switch (', me.addFn(action), me.callFn, ') {\n');
            }
            me.switches.push(0);
        },

        doCase: function (action) {
            var me = this,
                cases = Ext.isArray(action) ? action : [action],
                n = me.switches.length - 1,
                match, i;

            if (me.switches[n]) {
                me.body.push('break;\n');
            } else {
                me.switches[n]++;
            }

            for (i = 0, n = cases.length; i < n; ++i) {
                match = me.intRe.exec(cases[i]);
                cases[i] = match ? match[1] : ("'" + cases[i].replace(me.aposRe,"\\'") + "'");
            }

            me.body.push('case ', cases.join(': case '), ':\n');
        },

        doDefault: function () {
            var me = this,
                n = me.switches.length - 1;

            if (me.switches[n]) {
                me.body.push('break;\n');
            } else {
                me.switches[n]++;
            }

            me.body.push('default:\n');
        },

        doEnd: function (type, actions) {
            var me = this,
                L = me.level-1;

            if (type == 'for' || type == 'foreach') {
                /*
                To exit a for or foreach loop we must restore the outer loop's context. The
                code looks like this (which goes with that produced by doFor or doForEach):

                        for (...) { // the part generated by doFor or doForEach
                            ...  // the body of the for loop

                            // ... any tpl for exec statement goes here...
                        }
                        parent = p1;
                        values = r2;
                        xcount = n1;
                        xindex = i1
                */
                if (actions.exec) {
                    me.doExec(actions.exec);
                }

                me.body.push('}\n');
                me.body.push('parent=p',L,';values=r',L+1,';xcount=n'+L+';xindex=i',L,'+1;xkey=k',L,';\n');
            } else if (type == 'if' || type == 'switch') {
                me.body.push('}\n');
            }
        },

        doFor: function (action, actions) {
            var me = this,
                s,
                L = me.level,
                up = L-1,
                parentAssignment;

            // If it's just a propName, use it directly in the switch
            if (action === '.') {
                s = 'values';
            } else if (me.propNameRe.test(action)) {
                s = me.parseTag(action);
            }
            // Otherwise, it must be an expression, and needs to be returned from an fn which uses with(values)
            else {
                s = me.addFn(action) + me.callFn;
            }

            /*
            We are trying to produce a block of code that looks like below. We use the nesting
            level to uniquely name the control variables.

                // Omit "var " if we have already been through level 2
                var i2 = 0,
                    n2 = 0,
                    c2 = values['propName'],
                        // c2 is the context object for the for loop
                    a2 = Array.isArray(c2);
                    r2 = values,
                        // r2 is the values object
                    p2, // p2 is the parent context (of the outer for loop)
                    k2; // object key - not used by for loop but doEnd needs this to be declared

                // If iterating over the current data, the parent is always set to c2
                p2 = parent = c2;
                // If iterating over a property in an object, set the parent to the object
                p2 = parent = a1 ? c1[i1] : c1 // set parent
                if (c2) {
                    if (a2) {
                        n2 = c2.length;
                    } else if (c2.isMixedCollection) {
                        c2 = c2.items;
                        n2 = c2.length;
                    } else if (c2.isStore) {
                        c2 = c2.data.items;
                        n2 = c2.length;
                    } else {
                        c2 = [ c2 ];
                        n2 = 1;
                    }
                }
                // i2 is the loop index and n2 is the number (xcount) of this for loop
                for (xcount = n2; i2 < n2; ++i2) {
                    values = c2[i2]           // adjust special vars to inner scope
                    xindex = i2 + 1           // xindex is 1-based

            The body of the loop is whatever comes between the tpl and /tpl statements (which
            is handled by doEnd).
            */

            // Declare the vars for a particular level only if we have not already declared them.
            if (me.maxLevel < L) {
                me.maxLevel = L;
                me.body.push('var ');
            }

            if (action == '.') {
                parentAssignment = 'c' + L;
            } else {
                parentAssignment = 'a' + up + '?c' + up + '[i' + up + ']:c' + up;
            }

            me.body.push('i',L,'=0,n', L, '=0,c',L,'=',s,',a',L,'=', me.createArrayTest(L),',r',L,'=values,p',L,',k',L,';\n',
                'p',L,'=parent=',parentAssignment,'\n',
                'if (c',L,'){if(a',L,'){n', L,'=c', L, '.length;}else if (c', L, '.isMixedCollection){c',L,'=c',L,'.items;n',L,'=c',L,'.length;}else if(c',L,'.isStore){c',L,'=c',L,'.data.items;n',L,'=c',L,'.length;}else{c',L,'=[c',L,'];n',L,'=1;}}\n',
                'for (xcount=n',L,';i',L,'<n'+L+';++i',L,'){\n',
                'values=c',L,'[i',L,']');
            if (actions.propName) {
                me.body.push('.', actions.propName);
            }
            me.body.push('\n',
                'xindex=i',L,'+1\n');

            if (actions.between) {
                me.body.push('if(xindex>1){ out.push("',actions.between,'"); } \n');
            }
        },

        doForEach: function (action, actions) {
            var me = this,
                s,
                L = me.level,
                up = L-1,
                parentAssignment;

            // If it's just a propName, use it directly in the switch
            if (action === '.') {
                s = 'values';
            } else if (me.propNameRe.test(action)) {
                s = me.parseTag(action);
            }
            // Otherwise, it must be an expression, and needs to be returned from an fn which uses with(values)
            else {
                s = me.addFn(action) + me.callFn;
            }

            /*
            We are trying to produce a block of code that looks like below. We use the nesting
            level to uniquely name the control variables.

                // Omit "var " if we have already been through level 2
                var i2 = -1,
                    n2 = 0,
                    c2 = values['propName'], // c2 is the context object for the for loop
                    a2 = Array.isArray(c2);
                    r2 = values, // r2 is the values object
                    p2, // p2 is the parent context (of the outer for loop)
                    k2; // k2 is the object key while looping

                // If iterating over the current data, the parent is always set to c2
                p2 = parent = c2;
                // If iterating over a property in an object, set the parent to the object
                p2 = parent = a1 ? c1[i1] : c1 // set parent

                for(k2 in c2){
                    xindex = ++i + 1; // xindex is 1-based
                    xkey = k2;
                    values = c2[k2]; // values is the property value

            The body of the loop is whatever comes between the tpl and /tpl statements (which
            is handled by doEnd).
            */

            // Declare the vars for a particular level only if we have not already declared them.
            if (me.maxLevel < L) {
                me.maxLevel = L;
                me.body.push('var ');
            }

            if (action == '.') {
                parentAssignment = 'c' + L;
            } else {
                parentAssignment = 'a' + up + '?c' + up + '[i' + up + ']:c' + up;
            }

            me.body.push('i',L,'=-1,n',L,'=0,c',L,'=',s,',a',L,'=',me.createArrayTest(L),',r',L,'=values,p',L,',k',L,';\n',
                'p',L,'=parent=',parentAssignment,'\n',
                'for(k',L,' in c',L,'){\n',
                    'xindex=++i',L,'+1;\n',
                    'xkey=k',L,';\n',
                    'values=c',L,'[k',L,'];');
            if (actions.propName) {
                me.body.push('.', actions.propName);
            }

            if (actions.between) {
                me.body.push('if(xindex>1){ out.push("',actions.between,'"); } \n');
            }
        },

        createArrayTest: ('isArray' in Array) ? function(L) {
            return 'Array.isArray(c' + L + ')';
        } : function(L) {
            return 'ts.call(c' + L + ')==="[object Array]"';
        },

        doExec: function (action, actions) {
            var me = this,
                name = 'f' + me.definitions.length;

            me.definitions.push('function ' + name + '(' + me.fnArgs + ') {',
                                ' try { with(values) {',
                                '  ' + action,
                                ' }} catch(e) {',
                                //<debug>
                                'Ext.log("XTemplate Error: " + e.message);',
                                 //</debug>
                                '}',
                          '}');

            me.body.push(name + me.callFn + '\n');
        },

        //-----------------------------------
        // Internal

        addFn: function (body) {
            var me = this,
                name = 'f' + me.definitions.length;

            if (body === '.') {
                me.definitions.push('function ' + name + '(' + me.fnArgs + ') {',
                                ' return values',
                           '}');
            } else if (body === '..') {
                me.definitions.push('function ' + name + '(' + me.fnArgs + ') {',
                                ' return parent',
                           '}');
            } else {
                me.definitions.push('function ' + name + '(' + me.fnArgs + ') {',
                                ' try { with(values) {',
                                '  return(' + body + ')',
                                ' }} catch(e) {',
                                //<debug>
                                'Ext.log("XTemplate Error: " + e.message);',
                                 //</debug>
                                '}',
                           '}');
            }

            return name;
        },

        parseTag: function (tag) {
            var me = this,
                m = me.tagRe.exec(tag),
                name, format, args, math, v;

            if (!m) {
                return null;
            }

            name = m[1];
            format = m[2];
            args = m[3];
            math = m[4];

            // name = "." - Just use the values object.
            if (name == '.') {
                // filter to not include arrays/objects/nulls
                if (!me.validTypes) {
                    me.definitions.push('var validTypes={string:1,number:1,boolean:1};');
                    me.validTypes = true;
                }
                v = 'validTypes[typeof values] || ts.call(values) === "[object Date]" ? values : ""';
            }
            // name = "#" - Use the xindex
            else if (name == '#') {
                v = 'xindex';
            }
            // name = "$" - Use the xkey
            else if (name == '$') {
                v = 'xkey';
            }
            else if (name.substr(0, 7) == "parent.") {
                v = name;
            }
            // compound Javascript property name (e.g., "foo.bar")
            else if (isNaN(name) && name.indexOf('-') == -1 && name.indexOf('.') != -1) {
                v = "values." + name;
            }
            // number or a '-' in it or a single word (maybe a keyword): use array notation
            // (http://jsperf.com/string-property-access/4)
            else {
                v = "values['" + name + "']";
            }

            if (math) {
                v = '(' + v + math + ')';
            }

            if (format && me.useFormat) {
                args = args ? ',' + args : "";
                if (format.substr(0, 5) != "this.") {
                    format = "fm." + format + '(';
                } else {
                    format += '(';
                }
            } else {
                return v;
            }

            return format + v + args + ')';
        },

        // @private
        evalTpl: function ($) {

            // We have to use eval to realize the code block and capture the inner func we also
            // don't want a deep scope chain. We only do this in Firefox and it is also unhappy
            // with eval containing a return statement, so instead we assign to "$" and return
            // that. Because we use "eval", we are automatically sandboxed properly.
            eval($);
            return $;
        },

        newLineRe: /\r\n|\r|\n/g,
        aposRe: /[']/g,
        intRe:  /^\s*(\d+)\s*$/,
        tagRe:  /^([\w-\.\#\$]+)(?:\:([\w\.]*)(?:\((.*?)?\))?)?(\s?[\+\-\*\/]\s?[\d\.\+\-\*\/\(\)]+)?$/

    }, function () {
        var proto = this.prototype;

        proto.fnArgs = 'out,values,parent,xindex,xcount,xkey';
        proto.callFn = '.call(this,' + proto.fnArgs + ')';
    });