define(['./underscore', './_executeBound', './restArguments'], function (underscore, _executeBound, restArguments) {

  // Partially apply a function by creating a version that has had some of its
  // arguments pre-filled, without changing its dynamic `this` context. `_` acts
  // as a placeholder by default, allowing any combination of arguments to be
  // pre-filled. Set `_.partial.placeholder` for a custom placeholder argument.
  var partial = restArguments(function(func, boundArgs) {
    var placeholder = partial.placeholder;
    var bound = function() {
      var position = 0, length = boundArgs.length;
      var args = Array(length);
      for (var i = 0; i < length; i++) {
        args[i] = boundArgs[i] === placeholder ? arguments[position++] : boundArgs[i];
      }
      while (position < arguments.length) args.push(arguments[position++]);
      return _executeBound(func, bound, this, this, args);
    };
    return bound;
  });

  partial.placeholder = underscore;

  return partial;

});