31 Oct
2014
31 Oct
'14
5:22 p.m.
On Thu, Oct 30, 2014 at 8:50 PM, Roman Cheplyaka
liftA2 (<|>) b a
B A Right 42
(In the latter case I don't want A in the output…)
Wrap it into ExceptT (from the latest transformers), as in
runExceptT $ ExceptT a <|> ExceptT b
With the latest transformers, I still get B A Right 42 i.e. the A hasn't been eliminated. What am I missing? -- Kim-Ee