[Haskell-cafe] A foray into type-level programming, and getting stuck

Wolfgang Jeltsch g9ks157k at acme.softbase.org
Mon Mar 2 05:41:17 EST 2009

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:


Best wishes,

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