This might be a reasonable solution for the the "concatenation" operator
you want:
[This does not solve the numeric ambiguity - I think that is impossible.]
infixl 1 <<
class Stringable a where
(<<) :: String -> a -> String
instance Stringable a => Stringable [a] where
s << [] = s
s << (x:xs) = s << x << xs
instance Stringable Int where
s << x = s ++ show x
instance Stringable Char where
s << x = s ++ [x]
main = print $ "Maybe " << (2+2::Int) << " is " << 'a' << " solution"
I hope you find << sufficiently keyboard friendly ;-)
(If you don't like having to put a string as the first argument you could
define a constant
cout :: String
cout = ""
and write
cout << "Maybe " << (2+2::Int) << " is " << 'a' << " solution"
)
Worth noting is that many variants of this theme is possible using other
types than String to store the information:
(<<) :: Printable a => IO () -> a -> IO ()
(<<) :: Pretty a => Doc -> a -> Doc
...
Patrik Jansson
