[Haskell-cafe] <|> that short-circuits in IO ?
ky3 at atamo.com
Fri Oct 31 21:22:28 UTC 2014
On Thu, Oct 30, 2014 at 8:50 PM, Roman Cheplyaka <roma at ro-che.info> wrote:
> >> 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
i.e. the A hasn't been eliminated.
What am I missing?
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