[Haskell-cafe] Re: What does the Haskell type system do with "show (1+2)"?

Jared Updike wrote:

http://www.haskell.org/onlinereport/decls.html#default-decls http://www.haskell.org/tutorial/numbers.html#sect10.4

I still don't see, why it works for show but not for my_show.

On 1/12/06, Jeff.Harper@handheld.com wrote: [...]

...

class (Show a) => My_show a where my_show :: a -> String

If I let this be class My_show a where my_show :: a -> String

...

instance My_show Int where my_show a = show a ++ " :: Int"

instance My_show Integer where my_show a = show a ++ " :: Integer"

What is the difference to the builtin Show class? Christian