[Haskell-cafe] data vs newtype (was: newbie problems)
MR K P SCHUPKE
k.schupke at imperial.ac.uk
Mon Jul 5 14:08:48 EDT 2004
One difference is that Constuctors for 'data' can be curries,
whereas 'newtype' cannot:
data X a b c = X a b c
newtype X a b c = X (a,b,c)
But you have to balance this against newtypes being neater. Also data
can represend and abstract type:
data X
whereas newtype cannot, also data can represent unitary types:
data Y = Y
whereas newtype is limited to wrapping up void:
newtype Z = Z ()
Keean.
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