Re: [Haskell-beginners] print []

Good to know extension. And without it? On Tue, Aug 13, 2013 at 4:59 PM, Brandon Allbery wrote:

On Tue, Aug 13, 2013 at 10:46 AM, Lukas Lehner wrote:

...

That means ghc cannot infer the type. Is there a way how to # print flatten (List []) ? Or even more general, print [] without enforcing the type?

If you turn on the ExtendedDefaultRules extension ( `{-# LANGUAGE ExtendedDefaultRules #-}` pragma or `-X ExtendedDefaultRules` ghc option), ghc will infer () for the type just as ghci does. Note that this reduces type safety a bit, since ghc will now accept programs that have what otherwise would be type errors.

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

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