[rmonad] RMonadFix (was: "patch for the rmonad package")

Ganesh Sittampalam ganesh at earth.li
Thu Mar 19 18:01:06 EDT 2009


Hi,

>> On Fri, 7 Nov 2008, Peter Gavin wrote:
>> 
>>> I've needed to add support for MonadFix to rmonad.  I've attached a 
>>> patch with my code.

I've just realised that this leaves out a case for unEmbed (Bind (MFix m) 
f). In addition, I can't actually figure out how to write such a case and 
I am beginning to suspect it's not possible.

Any thoughts? I've been through the mfix laws in the source of 
Control.Monad.Fix, and also checked Erkok and Launchbury's mfix paper, and 
I can't see anything that can be sensibly used here. Hopefully I'm missing 
something, though.

Cheers,

Ganesh



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