Re: [Haskell-cafe] <|> that short-circuits in IO ?

With the latest transformers, I still get

B A Right 42

i.e. the A hasn't been eliminated.

What am I missing?

Can you show us your code? Looking at the source: http://hackage.haskell.org/package/transformers-0.4.1.0/docs/src/Control-Mon... http://hackage.haskell.org/package/transformers-0.4.1.0/docs/src/Control-Mon... both ExceptT and ErrorT have short-circuiting <|> and mplus. Chris