* Richard Eisenberg <eir@cis.upenn.edu> [2014-09-15 08:56:05-0400]
> Have you tried using closed type families with the type-level (==)
> operator from GHC 7.8's Data.Type.Equality? That's how I've done
> unions before. The key step is to use a closed type family to write a
> type family equation that triggers when two types do *not* equal.
>
> Let me know if you need more info...
Thanks. I will take a look for my education, but
I am on Debian, so no more, then ghc 7.6.3.

I found type-settheory package, but it fails to build.

--
Best regards, Dmitry Bogatov <KAction@gnu.org>,
Free Software supporter, esperantisto and netiquette guardian.
GPG: 54B7F00D

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