Module Data.Function
This module provides some utility functions for function application.
Exported Functions
fix
:: (a -> a) -> a 
fix f
is the least fixed point of the function f,
i.e. the least defined x
such that f x = x.
on
:: (a -> a -> b) -> (c -> a) -> c -> c -> b
on f g x y
applies the binary operation f
to the results of
applying operation g
to two arguments x
and y.
Thus, it transforms two inputs and combines the outputs.
(*) `on` f = \x y -> f x * f y
A typical usage of this operation is:
sortBy ((<=) `on` fst)