This package provides binary operators which allow for easy and more readable point-free function composition.
These are nearly identical to
>>>, the only difference being
.> is left-associative whereas
>>> is right-associative.
These operators let you compose a function of two arguments with a function of one argument.
f <.. g = \x y -> f (g x y)
Operators of this type exist up to
Here we encounter a new convention. While the
. has represented an argument that will be put through both functions, the
~ represents an argument that goes straight to the outer function.
f <~. g = \x y -> f x (g y)
All permutations of up to 4
.s where the symbols don't mix, the
~s are ahead of the
.s, with at least one
. exist as operators.
These operators use a similar convention for
~ as the composition operators above. They allow you to apply an argument to the second position in a function. You can think of the
~ as an empty space waiting to be filled.
f ~$ y = \x -> f x y
~$ is actually the familiar
flip function in operator form! These operators exist up to 3
Not only do these operators allow you to compose functions nicely, they also compose well with each other! Say I wanted to write
\x y -> f (g x) (h y)
point-free. No single operator can do that for you, but by combining them we can achieve this!
f <. g <~. h