Re: Superclass Cycle via Associated Type

2011-07-22 Thread Gábor Lehel
On Thu, Jul 21, 2011 at 6:46 PM, Simon Peyton-Jones simo...@microsoft.com wrote: You point is that the (C Int) dictionary has (C String) as a superclass, and (C String) has (C Int) as a superclass. So the two instances are mutually recursive, but that’s ok. That is not unreasonable. But it

RE: Superclass Cycle via Associated Type

2011-07-22 Thread Simon Peyton-Jones
I talked to Dimitrios. Fundamentally we think we should be able to handle recursive superclasses, albeit we have a bit more work to do on the type inference engine first. The situation we think we can handle ok is stuff like Edward wants (I've removed all the methods): class LeftModule

Re: Superclass Cycle via Associated Type

2011-07-22 Thread Gábor Lehel
2011/7/22 Simon Peyton-Jones simo...@microsoft.com: I talked to Dimitrios.  Fundamentally we think we should be able to handle recursive superclasses, albeit we have a bit more work to do on the type inference engine first. The situation we think we can handle ok is stuff like Edward wants

Re: Superclass Cycle via Associated Type

2011-07-22 Thread Edward Kmett
2011/7/22 Simon Peyton-Jones simo...@microsoft.com I talked to Dimitrios. Fundamentally we think we should be able to handle recursive superclasses, albeit we have a bit more work to do on the type inference engine first. The situation we think we can handle ok is stuff like Edward wants

Re: Superclass Cycle via Associated Type

2011-07-22 Thread Dan Doel
2011/7/22 Gábor Lehel illiss...@gmail.com: Yeah, this is pretty much what I ended up doing. As I said, I don't think I lose anything in expressiveness by going the MPTC route, I just think the two separate but linked classes way reads better. So it's just a would be nice thing. Do recursive

Re: haskell-platform configures failed on Ubuntu 11.04

2011-07-22 Thread Albert Y. C. Lai
On 11-07-22 02:26 PM, David Smith wrote: I tried to build the newest haskell-platform-2011.2.01 from source on Ubuntu 11.04, following the instructions http://www.vex.net/~trebla/haskell/haskell-platform.xhtml. But there was still an configure error. [...] checking for library containing

Re: Superclass Cycle via Associated Type

2011-07-22 Thread Ryan Trinkle
My situation is fairly similar to Gabor's, and, like him, I was able to make do with an equality superclass. However, instead of combining two classes, I found that I needed to add a third. My concept here is to create two monads which share much of their functionality, but not all of it.