Jonathan Cast wrote:
On Fri, 2008-10-03 at 20:43 +0100, Andrew Coppin wrote:
OK. So it's broken "for compatibility" then? (Presumably any time you
change something from the Prelude, mass breakage ensues!)
I'm not a big fan of backward-compatibility myself, but changing Monad
to be a sub-class of Applicative actually would have broken every monad
instance in existence (at the time Applicative was added, since it
didn't have any instances yet). I don't know what proportion of Haskell
programs/libraries/etc. have at least one Monad instance in them, but I
would guess it's high.
Hmm, that's quite a lot of breakage.
So if it had been set up this way from day 1, we wouldn't be having this
conversation, but it's now too expensive to change it. Is that basically
what it comes down to?
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