Benutzer:Dirk Hünniger/has

Aus Wikibooks
import Data.Monoid

instance Monoid Integer where
        mempty  =  (fromInteger 0)
        mappend a b= a+b

l= [(1+),(2+),(3+)]

j::Integer->Integer
j = mconcat l

main = print (j 12)

--and there was light