kiwi/lib/tags/print.js

Simple, modular, fast and lightweight template engine, based on jQuery templates syntax.

/*!
 * Coolony's Kiwi
 * Copyright ©2012 Pierre Matri <pierre.matri@coolony.com>
 * MIT Licensed
 */


/**
 * Module dependencies
 */

// if node
var _ = require('underscore');
// end

var filter = require('../filter');
var utils = require('../utils');


/**
 * Constants
 */

var TAG_REPLACE_RE = /\$\{([^\}]*)\}/g;
var TAG_PARSE_RE = /^(?:=|html)\s+(?:\:(\d+)\s+)?([^|]+)(?:\|(.*))?$/;
var DEFAULT_VARIABLE_FILTERS = ['escapeIfUnsafe'].map(JSON.stringify);
var DEFAULT_HTML_FILTERS = [];


/**
 * Global variables
 */

module.exports.tags = {};
var variableTag = module.exports.tags['='] = {};
var htmlTag = module.exports.tags['html'] = {};


/**
 * Basic tag settings
 */

variableTag.isBlock = false;
htmlTag.isBlock = false;


/**
 * Before Processor.
 * Replace "${…}" to "{{= …}}" in `source`, and invoke
 * `callback(err, replaced)`.
 *
 * @param {String} source
 * @param {Function} callback
 * @api private
 */

variableTag.beforeProcessor = function(source, compiler, callback) {
  compiler.__print = [];
  source = source.replace(TAG_REPLACE_RE, function(all, contents) {
    compiler.__print.push(all);
    return '{{= :' + compiler.__print.length + ' ' + contents + '}}';
  });
  callback(null, source);
};


/**
 * Compilers.
 */

variableTag.compile = createPrintTagCompiler(DEFAULT_VARIABLE_FILTERS);
htmlTag.compile = createPrintTagCompiler(DEFAULT_HTML_FILTERS);


/**
 * Create print tag based on `defaultFilters`.
 * Return `function(token, compiledContents, compiler, callback)`.
 *
 * @param {Array} defaultFilters
 * @return {Function}
 * @api private
 */

function createPrintTagCompiler(defaultFilters) {
  var compiler = function(token, compiledContents, compiler, callback) {
    var parsed = token.tag.match(TAG_PARSE_RE);

    if(!parsed) {
      return callback(new Error('Compilation error: Unable to parse tag `' +
                                token.tag +
                                '`.'
                                ));
    }

    // Handle decompiler
    if(parsed[1]) {
      var key = parseInt(parsed[1], 10) - 1;
      token.__originalTag = compiler.__print[key];
    }

    var contents = parsed[2];
    var filters;
    
    try {
      filters = parsed[3] ? utils.parseFilters(parsed[3], defaultFilters) :
                            defaultFilters;
    } catch(err) {
      return callback(err);
    }
                              
    contents = '$tools.filter(' +
               contents +
               ', ' +
               '[' + filters.join(',') + ']' +
               ')';

    var ret;

    if(!token.options.strict) {
      ret = 'try {' +
              'var __tmp = ' + contents + ';' +
            '} catch(__err) {' +
              'if(__err instanceof ReferenceError) {' +
                '__tmp = "";' +
              '} else {' +
                'throw __err;' +
              '}' +
            '}' +
            '__acc.push(__tmp);';
    } else {
      ret = '__acc.push(' + contents + ');';
    }
    callback(null, ret);
  };

  compiler.untokenize = function(token, compiler) {
    return token.__originalTag ?
             token.__originalTag :
             ('{{' + token.tag + '}}');
  };

  return compiler;
}