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

[Semen Trygubenko / Семен Тригубенко]

Dear Haskell-Cafe,

Is there a way to get Control.Applicative.<|> to short-circuit when combining two IO actions?

E.g.

> let a = putStrLn "A" >> return (Left "hehe")
> let b = putStrLn "B" >> return (Right 42)

> Prelude> liftA2 (<|>) a b

A
B
Right 42

> liftA2 (<|>) b a

B
A
Right 42

(In the latter case I don't want A in the output…)

Many thanks for your help,
Semen



-- 
Семен Тригубенко http://trygub.com
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