[Haskell-cafe] AbstractDataType question
tomasz.zielonka at gmail.com
Sun Dec 12 17:25:00 EST 2004
On Sun, Dec 12, 2004 at 07:46:42PM +0100, Sebastian Sylvan wrote:
> > Could someone point me to some documentation on whats being created here
> > and how its used?
> It's basically a shorthand for writing accessor functions.
> You could do something like:
> data Tree a = Nil | Node (Tree a) a (Tree a)
> left (Node l _ _) = l
> value (Node _ v _) = v
> right (Node _ _ r) = r
Record field labels can be also used in pattern matching and in
record update. Especially the latter is very useful. For more
information, see The Haskell 98 Report.
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