Gábor Lehel
On Fri, May 25, 2012 at 7:06 AM, AntC
wrote:
But it looks like the work SPJ pointed to is using closed style. ...
If you're referring to the NewAxioms work Simon linked to in the other thread, I don't see it explicitly stated that all instances have to be within a single module. Especially section 3.3 (Translation) of the pdf[1] seems to suggest otherwise. Though it also doesn't seem to be the same as what you're asking for. As far as I can tell, with NewAxioms, wherever you could currently have a type instance, you could instead have a type instance group. ... [snip]
Thanks Gábor, I think you could be right. (It needs some pretty close reading of the equations.) I think in this case an example would be worth a thousand typevars - double-barred of course. I told them in Hebrew, I told them in Dutch, I told them in Latin and Greek, But I clear forgot (and it vexes me much), That Haskell is what they speak. The NewAxioms (draft) paper has a reference to Oleg's HList, but not his Type- level Typeable, nor to Salzmann & Stuckey (2002), Chameleon, nor the myriad discussions in the cafe and Haskell Prime. It would be nice to see a statement along the lines of: we looked at X, Y and Z, and didn't follow that approach because ...; or we believe that approach can be incorporated like this ... I thought it was a good research discipline to start with a literature survey, to avoid re-inventing the wheel(?)
It seems vaguely similar to a paper on instance chains[2] I saw once.
Thanks, I saw that a while back but didn't look into it much at the time. There's heaps of approaches out there to type-safe overlaps. Perhaps they're all logically equivalent(?) So perhaps we're only bikeshedding about surface syntax(??) AntC