modules/keywords.js

   1 /**
   2  * (C) Copyright 2007-2008 Jeremy Maitin-Shepard
   3  *
   4  * Use, modification, and distribution are subject to the terms specified in the
   5  * COPYING file.
   6  **/
   7
   8 var _keyword_argument_list = [];
   9 function _get_keyword_argument_setter (name) {
  10     return function (value) { _keyword_argument_list.push(name); return value; };
  11 }
  12
  13 function _get_keyword_argument_getter (name) {
  14     return function () { _keyword_argument_list.push(name); return true; };
  15 }
  16
  17 // This function must be called with all string arguments, all of
  18 // which must begin with "$".
  19 function define_keywords () {
  20     for (var i = 0, alen = arguments.length; i < alen; ++i) {
  21         var name = arguments[i];
  22         this.__defineSetter__(name, _get_keyword_argument_setter(name));
  23         this.__defineGetter__(name, _get_keyword_argument_getter(name));
  24     }
  25 }
  26
  27 var define_keyword = define_keywords;
  28
  29 function write_keywords (output, input, first_index) {
  30     if (first_index == null) {
  31         first_index = input.callee.length;
  32     }
  33     let max_index = input.length;
  34     let count = max_index - first_index;
  35     if (count > 0) {
  36         let offset = _keyword_argument_list.length - 1;
  37         for (let i = max_index - 1; i >= first_index; --i) {
  38             let value = input[i];
  39             if (value instanceof keyword_argument_forwarder) {
  40                 for (let x in value)
  41                     output[x] = value[x];
  42                 --count;
  43             } else {
  44                 let name = _keyword_argument_list[offset--];
  45                 output[name] = value;
  46             }
  47         }
  48         _keyword_argument_list.length -= count;
  49     }
  50 }
  51
  52 function keyword_argument_forwarder (args) {
  53     if ("_processed_keywords" in args) {
  54         for (let x in args) {
  55             if (x[0] == "$")
  56                 this[x] = args[x];
  57         }
  58     } else {
  59         write_keywords(this, args);
  60     }
  61 }
  62
  63 function keywords (args) {
  64     write_keywords(args, arguments);
  65     write_keywords(args, args);
  66     args._processed_keywords = true;
  67 }
  68
  69 function forward_keywords (args) {
  70     return new keyword_argument_forwarder(args);
  71 }
  72
  73 function protect_keywords () {
  74     return new keyword_argument_forwarder(arguments);
  75 }
  76
  77 provide("keywords");