Naming of `pure` function in Control.Applicative [closed]
-
26-09-2019 - |
문제
Why is the function for lifting a value into a functor named pure
in Control.Applicative?
해결책
Think of pure
as an adjective.
foo <*> pure 4
= foo
applied on a pure value 4
.
(As for the exact reason why it's called pure
, probably only McBride and Paterson will know.)
다른 팁
It's a little like fromInteger
. Its argument is always a pure value or function that will be lifted into the functor. Perhaps it should have been fromPure
but you know how Haskell people love to shorten names (e.g. fst
and snd
instead of first
and second
...).
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