[Haskell] Re: manipulating untyped lambda-calculus in Haskell

[Chung-chieh Shan]

Vivian McPhail <vivian.mcphail at paradise.net.nz> wrote in article <001301c54d6c$ba44b980$0301a8c0 at intranet> in gmane.comp.lang.haskell.general:
> It seems that I must be missing something?  Is there a more elegant
> way of doing this?

Check out the "generalized algebraic data types" feature (GADT, one of
its many names), now available in GHC.  One classical example of its use
is to write type-safe interpreters similar to your NL parser.

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