Re: [Haskell-cafe] Type classes for converting to Text and String

On Thu, Mar 08, 2012 at 11:00:34AM +0100, Christopher Done wrote:

On 8 March 2012 10:53, Simon Hengel wrote:

...

When writing library code that should work with both String and Text I find my self repeatedly introducing classes like:

   class ToString a where      toString :: a -> String

   class ToText a where      toText :: a -> Text

Text is already an instance of IsString which provides IsString.

What exactly do you mean?

I've defined ToString in my own projects though, it would be nice for it to be defined somewhere (Data.String maybe?).

We could write a proposal to add ToString to base (maybe a good idea, not sure). ToString has a striking similarity with Show, but it's still different: * toString converts some a to a String * show gives a string _representation_ of some a (e.g. converting a String to a String is just id and hence different from show; this is akin to Python's __str__/__repr__) But this does still not help with toText. Cheers, Simon