The type of "hello" is String, which is [Char], which is really [] Char (that is, the list type of kind * -> *, applied to Char). 1, 'a', and True are all simple types (I'm sure there's a more particular term, maybe "monomorphic"?) with no type arguments. [] has a type argument, Char. Consider: Prelude Data.Typeable> typeRepArgs (typeOf (Just 1)) [Integer] and Prelude Data.Typeable> typeRepArgs (typeOf (Left 'a' :: Either Char Int)) [Char,Int] -- typeRepArgs is giving you the arguments of the root type application, [] (list) in your case, Maybe and Either for the two examples I gave. Does this make sense? -Ross On Feb 2, 2009, at 3:09 PM, minh thu wrote:
Hello,
With Data.Typeable :
*Graph> typeRepArgs (typeOf 1) [] *Graph> typeRepArgs (typeOf 'a') [] *Graph> typeRepArgs (typeOf True) [] *Graph> typeRepArgs (typeOf "hello") [Char]
I don't understand why the latter is not []. Could someone explain it ?
Thank you, Thu _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe