31 Jul
2014
31 Jul
'14
11 a.m.
Konstantine Rybnikov
Excuse me if the question is silly.
Thought this MonadCatchIO will be removed in next version of snap, current version has it and I can't understand this derivation: [0]
L.Lensed seems like just a newtype wrapper around a function [1], and there is no instance of MonadCatchIO for a function.
How is it derived?
You probably just missed it, but there's a MonadCatchIO instance for L.Lensed, and so the derived instance for Handler is trivial.