[Haskell-cafe] Very silly
Andrew Coppin
andrewcoppin at btinternet.com
Mon Oct 13 16:17:56 EDT 2008
Jonathan Cast wrote:
> Flexible instances are extroardinarily useful:
>
I'm sure the GHC team wouldn't have bothered otherwise. ;-)
AFAIK, "flexible instances" just means that absolutely anything can be a
class instance, right?
> instance Monad m => MonadState s (StateT s m)
> instance MonadState t m => MonadState (s, t) (StateT s m)
>
> is a useful and not entirely insane instance scheme.
>
I hadn't realised this required FIs. (Although clearly it demands
MPTCs.) Man, so many TLAs...
> But yeah, anyone who uses class Silly in real life should be banned from
> coming within a 100 feet of any place where math, science, engineering,
> or software development is carried out or taught.
>
> I don't know if it's necessary for the good of the Children, but we need
> to start thinking of the poor, defenseless computers as well...
>
Heh. And I thought *I* was crewl for making my poor PC use Peano
integers rather than the [vastly more efficient] binary numbers...
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