[Haskell-cafe] Backward compatibility

[Tobias Dammers]

On Fri, May 03, 2013 at 01:23:55PM +0300, Guy wrote:
> That's what I thought of when I saw the original complaint - GHC is
> too backwards compatible! There's far too much boilerplate because
> of the Functor => Applicative => Monad mess. Float/Double being
> Enums is ridiculous. None of this gets fixed because of the fear
> that new GHC won't compile old code.

> 
> PS The proposal to fix Functor => Applicative => Monad has patches
> attached for GHC and base, but the backwards compatibility bogeyman
> always seems to trump something that will break a lot of code.

This kind of "breaks everything" changes would require something similar
to what Python is doing with the 2 -> 3 transition, and considering how
painfully slowly it is progressing there, I understand perfectly well why
people don't want to go there.