[Haskell-cafe] Monad of no `return` Proposal (MRP): Moving `return` out of `Monad`

Richard A. O'Keefe ok at cs.otago.ac.nz
Thu Oct 8 03:58:45 UTC 2015

The change to make Monad a special case of Applicative has been
a long time coming, and it has been a long time coming precisely
because it's going to break things.

I feel ambivalent about this.  As soon as the question was
raised, it was clear that it *would have been* nicer had
Haskell been this way originally.  I'm not looking forward to
the consequences of the change.

On 7/10/2015, at 12:32 am, Henrik Nilsson <Henrik.Nilsson at nottingham.ac.uk> wrote:
> While we can discuss the extent of additional breakage
> MRP would cause, the fact remains it is a further
> breaking change. A survey of breakage to books as
> Herbert did is certainly valuable  (thanks!), but
> much breakage will (effectively) remain unquantifiable.

This suggests one way in which one of the costs of the change
could be reduced.  Not just to survey the breakage, but to
actually put revised material up on the Haskell.org web site,
with a prominent link from the home page.

More information about the Haskell-Cafe mailing list