[Haskell-cafe] unary pattern matching
Donald Bruce Stewart
dons at cse.unsw.edu.au
Thu Jan 26 20:28:23 EST 2006
> I have often wanted a shorthand syntax for testing if a value matches a
> given pattern. I want to implement such an extension for jhc but can't
> decide an appropriate syntax so I thought I'd ask the group. basically I
> want something like
> /Left (Just _)/ expands to
> \x -> case x of
> Left (Just _) -> True
> _ -> False
Something like pattern guards?
f x | Just _ <- x = putStrLn "something"
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