sebastian-software/core

/*
==================================================================================================
  Core - JavaScript Foundation
  Copyright 2010-2012 Zynga Inc.
  Copyright 2012-2014 Sebastian Werner
--------------------------------------------------------------------------------------------------
  Based on the work of:
  Hogan.JS by Twitter, Inc.
  https://github.com/twitter/hogan.js
  Licensed under the Apache License, Version 2.0
  http://www.apache.org/licenses/LICENSE-2.0
==================================================================================================
*/

"use strict";

(function ()
{
    var escapeMatcher = /[\\\"\n\r]/g;

    var escapeMap = {
        "\\" : '\\\\',
        "\"" : '\\\"',
        "\n" : '\\n',
        "\r" : '\\r'
    };

    var escapeReplacer = function(str) {
        return escapeMap[str];
    };

    var accessTags =
    {
        "#" : 1, // go into section / loop start
        "?" : 1, // if / has
        "^" : 1, // if not / has not
        "$" : 1, // insert variable
        "=" : 1  // insert raw / non escaped
    };

    // Tags which support children
    var innerTags =
    {
        "#" : 1,
        "?" : 1,
        "^" : 1
    };

    function walk(node, labels, nostrip)
    {
        var code = '';

        for (var i=0, l=node.length; i<l; i++)
        {
            var current = node[i];
            var tag = current.tag;

            if (tag == null)
            {
                code += 'buf+="' + current.replace(escapeMatcher, escapeReplacer) + '";';
            }
            else if (tag == '\n')
            {
                code += 'buf+="\\n";';
            }
            else
            {
                var name = current.name;
                var escaped = name.replace(escapeMatcher, escapeReplacer);

                if (tag in accessTags)
                {
                    var accessor = name == "." ? 2 : ~name.indexOf('.') ? 1 : 0;
                    var accessorCode = '"' + escaped + '",' + accessor + ',data';

                    if (tag in innerTags) {
                        var innerCode = walk(current.nodes, labels, nostrip);
                    }

                    if (tag == '?') {
                        code += 'if(this._has(' + accessorCode + ')){' + innerCode + '}';
                    } else if (tag == '^') {
                        code += 'if(!this._has(' + accessorCode + ')){' + innerCode + '}';
                    } else if (tag == '#') {
                        code += 'this._section(' + accessorCode + ',partials,labels,function(data,partials,labels){' + innerCode + '});';
                    } else if (tag == '=') {
                        code += 'buf+=this._data(' + accessorCode + ');';
                    } else if (tag == '$') {
                        code += 'buf+=this._variable(' + accessorCode + ');';
                    }
                }
                else if (tag == '>')
                {
                    code += 'buf+=this._partial("' + escaped + '",data,partials,labels);';
                }
                else if (tag == '_')
                {
                    // Support either static labels and dynamic labels
                    var resolved = labels && labels[escaped];
                    if (typeof resolved == "string") {
                        code += walk(core.template.Parser.parse(resolved, true), labels);
                    } else {
                        code += 'buf+=this._label("' + escaped + '",data,partials,labels);';
                    }
                }
            }
        }

        return code;
    }


    /**
     * This is the Compiler of the template engine and transforms the token tree into a compiled template instance.
     */
    core.Module("core.template.Compiler",
    {
        /**
         * {core.template.Template} Translates the @code {Array} tree from {core.template.Parser#parse} into actual JavaScript
         * code (in form of a {core.template.Template} instance) to insert dynamic data fields. It uses
         * the original @text {String} for template construction. There is also the possibility to inject
         * static @labels {Map} at compile time level or resolve them dynamically at every rendering.
         * Optionally you can keep white spaces (line breaks, leading, trailing, etc.) by
         * enabling @nostrip {Boolean?false}. Additionally one can define a template @name {String} for
         * improved debugging capabilities.
         */
        compile : function(text, labels, nostrip, name)
        {
            var tree = core.template.Parser.parse(text, nostrip);
            var wrapped = 'var buf="";' + walk(tree, labels, nostrip) + 'return buf;';

            return new core.template.Template(new Function('data', 'partials', 'labels', wrapped), text, name);
        }
    });
})();