documentcloud/underscore — pull request #678 by Stebalien (2012-07-19 15:38:02+00:00)
Title: Add a mask function

Description: Add a mask function that takes a function and a variable
number of indices and returns a function that calls the passed function
with the arguments specified by the indices in order.

_.mask(f, 2, 0)(a, b, c, d) is equivalent to f(c, a)

Use case: Mask out and/or rearrange arguments to a callback without a
closure.