If only for those watching from home, here are some references. jeff p <[EMAIL PROTECTED]> wrote in article <[EMAIL PROTECTED]> in gmane.comp.lang.haskell.general: > >Better yet, > > how about LambdaProlog ( > > http://www.lix.polytechnique.fr/Labo/Dale.Miller/lProlog), > > which generalizes from Horn clauses to (higher-order) hereditary Harrop > > formulas, including (restricted but powerful) universals, implication, and > > existentials? > Having hereditary Harrop formulas at the type level would be cool. It > would also probably require type level lambdas.
On that note: Trifonov, Valery. 2003. Simulating quantified class constraints. In Proceedings of the 2003 Haskell workshop, 98-102. New York: ACM Press. http://flint.cs.yale.edu/trifonov/papers/sqcc.pdf http://flint.cs.yale.edu/trifonov/papers/sqcc.ps.gz > There was a recent discussion about type level lambdas in Haskell > which ended with the observations that 1) it would mess up unification > (i.e. make it undecidable and/or too hard) to have explicit type level > lambdas; and 2) they are already implicitly there (this was pointed > out by Oleg) since one can define a type level application and type > level functions. I think 1) is a bit of a cop-out since you could > always restrict to pattern unification (L-lamda unification) which is > decidable and has MGUs. On that note: Neubauer, Matthias, and Peter Thiemann. 2002. Type classes with more higher-order polymorphism. In ICFP '02: Proceedings of the ACM international conference on functional programming. New York: ACM Press. http://www.informatik.uni-freiburg.de/~neubauer/papers/icfp02.pdf http://www.informatik.uni-freiburg.de/~neubauer/papers/icfp02.ps.gz -- Edit this signature at http://www.digitas.harvard.edu/cgi-bin/ken/sig "Injustice is happening now; suffering is happening now. We have choices to make now. To insist on absolute certainty before starting to apply ethics to life decisions is a way of choosing to be amoral." -Richard Stallman _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
