Functor => Applicative => Monad

Simon Marlow marlowsd at
Wed Dec 22 18:03:54 CET 2010

On 14/12/2010 08:35, Isaac Dupree wrote:
> On 12/14/10 03:13, John Smith wrote:
>> I would like to formally propose that Monad become a subclass of
>> Applicative, with a call for consensus by 1 February. The change is
>> described on the wiki at
> That page isn't written as a proposal yet, it's written as a bunch of
> ideas. I would be happy to see something along the lines of Bas van
> Dijk's work
> .

This is a proposal with far-reaching consequences, and with several 
alternative designs. I'm not sure I understand all the tradeoffs.  Some 
parts of the proposal are orthogonal to the rest (e.g. changing fmap to 
map), and should probably be considered separately.

Could someone please write a detailed proposal, enumerating all the pros 
and cons, and the rationale for this design compared to other designs?


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