code: function parse(str, options) {
    var obj = options.object || 'obj'
      , space = options.pretty ? 2 : 0
      , space = options.spaces ? options.spaces : space
      , js = str;
    
    return ''
      + 'var ' + obj + ' = factory();\n'
      + (options.self
        ? 'var self = locals || {};\n' + js
        : 'with (locals || {}) {\n' + js + '\n}\n')
      + 'return JSON.stringify(' + obj + ', null, ' +  space + ')';
  }
docs: Parse the given `str` of JSON builder and return a function body.
  
  @param {String} str
  @param {Object} options
  @return {String}
  @api private