
2 Mar
2009
2 Mar
'09
5:41 a.m.
Am Sonntag, 1. März 2009 22:10 schrieb Brian Bloniarz:
Hi George,
Since none of the type metaprogramming specialists have answered you on-list, I took a crack at this -- I think you can work around the issue by avoiding overlapping instances entirely. I learned about this technique from the HList paper & this message: http://okmij.org/ftp/Haskell/keyword-arguments.lhs (see "the rest of the implementation").
Note that HList still needs overlapping instances for implementing type equality. If we will have closed type families at some future time, this will change. See: http://www.mail-archive.com/glasgow-haskell-users%40haskell.org/msg12792.htm... Best wishes, Wolfgang