On Apr 7, 2008, at 12:12 , PR Stanley wrote:
Hi data Bool = False | True deriving (Eq, Or, Show, Read)
Bool is an instance of Eq, Ord, Show and Read. It is derived form these classes. If that is the meaning of the keyword deriving then wouldn't a different keyword such as from or derivative or even derivation be closer to the semantics of the concept?
"deriving" doesn't declare superclasses; it means "please auto- generate code for me implementing instances for these classes". See http://haskell.org/onlinereport for the semantics of automatic instance deriving. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH