1) Is this the right place for newbies to post questions about Haskell?
pred :: Int -> Int
pred 0 = 0
pred n+1 = n
n+k patterns were part of Haskell '98, but removed from Haskell 2010. You may be able to use the pragma
{-# LANGUAGE NPlusKPatterns #-}
to turn them back on.
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