[Haskell-cafe] Restrict values in type

Luke Clifton ltclifton at gmail.com
Mon Jan 13 04:12:32 UTC 2014

Hi Bob,

You can have a heterogeneous list of items that implement a typeclass if
> you have a wrapper that uses ExistentialQuantification. See
> http://www.haskell.org/haskellwiki/Heterogenous_collections

Hmm.. I'll take a closer look at that. It might be good enough, though I
would prefer to be able to pattern match on the elements in the list.


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