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 {
   9     let _keyword_argument_list = [];
  10     let _get_keyword_argument_setter = function _get_keyword_argument_setter(name) {
  11         return function (value) { _keyword_argument_list[_keyword_argument_list.length] = name; return value; }
  12     }
  13
  14     let _get_keyword_argument_getter = function _get_keyword_argument_getter(name) {
  15         return function () { _keyword_argument_list[_keyword_argument_list.length] = name; return true; }
  16     }
  17
  18     // This function must be called with all string arguments, all of
  19     // which must begin with "$".
  20     function define_keywords()
  21     {
  22         for (var i = 0; i < arguments.length; ++i)
  23         {
  24             var name = arguments[i];
  25             this.__defineSetter__(name, _get_keyword_argument_setter(name));
  26             this.__defineGetter__(name, _get_keyword_argument_getter(name));
  27         }
  28     }
  29
  30     var define_keyword = define_keywords;
  31
  32     function write_keywords(output, input, first_index) {
  33         if (first_index == null)
  34             first_index = input.callee.length;
  35         let max_index = input.length;
  36         let count = max_index - first_index;
  37         if (count > 0) {
  38             let offset = _keyword_argument_list.length - 1;
  39             for (let i = max_index - 1; i >= first_index; --i) {
  40                 let value = input[i];
  41                 if (value instanceof keyword_argument_forwarder) {
  42                     for (let x in value)
  43                         output[x] = value[x];
  44                     --count;
  45                 } else {
  46                     let name = _keyword_argument_list[offset--];
  47                     output[name] = value;
  48                 }
  49             }
  50             _keyword_argument_list.length -= count;
  51         }
  52     }
  53
  54     let keyword_argument_forwarder = function keyword_argument_forwarder(args) {
  55         if ("_processed_keywords" in args) {
  56             for (let x in args) {
  57                 if (x[0] == "$") {
  58                     this[x] = args[x];
  59                 }
  60             }
  61         } else
  62             write_keywords(this, args);
  63     }
  64
  65     function keywords(args) {
  66         write_keywords(args, arguments);
  67         write_keywords(args, args);
  68         args._processed_keywords = true;
  69     }
  70
  71     function forward_keywords(args) {
  72         return new keyword_argument_forwarder(args);
  73     }
  74
  75     function protect_keywords() {
  76         return new keyword_argument_forwarder(arguments);
  77     }
  78 }