How do you compose functions in PureScript?

Question

Tried to use (.) for function composition, but it doesn't work.

import Data.String (length, trim)

trimmedLength :: String -> Int
trimmedLength = length . trim

score 17 · Accepted Answer · answered Sep 16 '17 at 11:02

17

Function composition in PureScript is done with (<<<), not (.).

import Data.String (length, trim)

trimmedLength :: String -> Int
trimmedLength = length <<< trim

answered Sep 16 '17 at 11:02

dontexist

That's verbose. Doesn't puresript supports unicode and hence could have `∘`? – Sep 16 '17 at 12:04
1

Yes, it's just not included in the core `Prelude`. Project-specific preludes will often define this if they're in unicode-friendly projects. – gb. Sep 16 '17 at 13:11
As of a couple of minutes ago, there's a library that (so far) does only this - [purescript-gorgeous](https://github.com/slamdata/purescript-gorgeous) - although it's not published on Pursuit yet. – dontexist Sep 16 '17 at 19:44

1 Answers1