[Haskell-cafe] do we have something like isDefined or isNull in Haskell?

Suppose there is a data definition in Haskell: data MyType = MyType { date :: Double, weight :: Double, height :: Double } deriving (Eq, Ord, Show) Is it possible to check if the field height, for example, is filled in(defined)? Can we give default values in Haskell? Many thanks and sorry fro so sily questions. Vladimir _________________________________________________________________ The new MSN Search Toolbar now includes Desktop search! http://join.msn.com/toolbar/overview