nex3/sass — pull request #439 by StanAngeloff (2012-07-04 19:15:24+00:00)
Title: Add `adjust-by` as a built-in number function

This function allows any number, incl. those with units, to be
manipulated by adding to/subtracting from them. Example:

adjust-by(10px, 10%) => 11px

In template design, it is very often the case a unit is selected
and all computations then cast between the selected unit. A very
hacky approach already exists:

$base: 10px;
($base / 1px) * 1.1 * 1px => 11px

but is less than ideal.