1  var baseRest = require('./_baseRest'),
 2      createWrap = require('./_createWrap'),
 3      getHolder = require('./_getHolder'),
 4      replaceHolders = require('./_replaceHolders');
 5  
 6  /** Used to compose bitmasks for function metadata. */
 7  var WRAP_BIND_FLAG = 1,
 8      WRAP_PARTIAL_FLAG = 32;
 9  
10  /**
11   * Creates a function that invokes `func` with the `this` binding of `thisArg`
12   * and `partials` prepended to the arguments it receives.
13   *
14   * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
15   * may be used as a placeholder for partially applied arguments.
16   *
17   * **Note:** Unlike native `Function#bind`, this method doesn't set the "length"
18   * property of bound functions.
19   *
20   * @static
21   * @memberOf _
22   * @since 0.1.0
23   * @category Function
24   * @param {Function} func The function to bind.
25   * @param {*} thisArg The `this` binding of `func`.
26   * @param {...*} [partials] The arguments to be partially applied.
27   * @returns {Function} Returns the new bound function.
28   * @example
29   *
30   * function greet(greeting, punctuation) {
31   *   return greeting + ' ' + this.user + punctuation;
32   * }
33   *
34   * var object = { 'user': 'fred' };
35   *
36   * var bound = _.bind(greet, object, 'hi');
37   * bound('!');
38   * // => 'hi fred!'
39   *
40   * // Bound with placeholders.
41   * var bound = _.bind(greet, object, _, '!');
42   * bound('hi');
43   * // => 'hi fred!'
44   */
45  var bind = baseRest(function(func, thisArg, partials) {
46    var bitmask = WRAP_BIND_FLAG;
47    if (partials.length) {
48      var holders = replaceHolders(partials, getHolder(bind));
49      bitmask |= WRAP_PARTIAL_FLAG;
50    }
51    return createWrap(func, bitmask, thisArg, partials, holders);
52  });
53  
54  // Assign default placeholders.
55  bind.placeholder = {};
56  
57  module.exports = bind;