[Haskell-cafe] Is it possible to print out types of instances in
lemmih at gmail.com
Sun Jan 16 06:09:43 EST 2005
On Sun, 16 Jan 2005 00:13:08 -0800, Jeremy Shaw
<jeremy.shaw at linspireinc.com> wrote:
> Is it possible to write a function that would display all the instances
> of a class currently in scope?
> For example, for 'Show a' it should output something like:
> The instances of 'Show a' currently in scope are:
> Show Int
> Show Float
> Show Char
> Show ...
In GHC 6.3:
Prelude> :i Show
class Show a where
showsPrec :: Int -> a -> String -> String
show :: a -> String
showList :: [a] -> String -> String
-- Imported from `GHC.Show'
instance Show IOMode -- Imported from `GHC.IOBase'
instance Show IOException -- Imported from `GHC.IOBase'
instance Show IOErrorType -- Imported from `GHC.IOBase'
instance Show HandleType -- Imported from `GHC.IOBase'
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