[Haskell-cafe] Type classes for converting to Text and String
sol at typeful.net
Thu Mar 8 11:42:35 CET 2012
On Thu, Mar 08, 2012 at 11:00:34AM +0100, Christopher Done wrote:
> On 8 March 2012 10:53, Simon Hengel <sol at typeful.net> 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
* 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.
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