2 Oct
2001
2 Oct
'01
11:19 a.m.
"Cagdas Ozgenc"
Could you help me on this notation?
Perhaps?
data Foo = Foo { a :: Int, b :: String }
This declares a Foo constructor with two named fields, and Int "a" and a String "b". This is equivalent to declaring data Foo = Foo Int String but with a couple of extra features added, among others that you automatically get defined functions "a" and "b" which take a Foo object and return the values of the respective parts.
instance Show Foo where show f = show (a f) ++ " " ++ show (b f)
...so the (a f) and (b f) parts are just extracting the relevant information from the Foo. If you know Lisp, it's fairly similar to defstruct. -kzm -- If I haven't seen further, it is by standing in the footprints of giants