[Haskell-cafe] Type-level lambdas in Haskell? ( was Multiparameter class error)

[Jim Apple]

On 2/21/07, Alfonso Acosta <alfonso.acosta at gmail.com> wrote:
> In my opinion adding Type-level lambdas would be the way to go, but
> they unfortunately are not part of Haskell.
>
[snip]
>
> Is there any extension to the language covering type-level lambdas or
> even a plan to include them in next revision?

SPJ suggested that type lambdas aren't in GHC because they unification
for type inference impossible:

http://www.mail-archive.com/haskell@haskell.org/msg10623.html

The feature list for EHC indicates that it does support type lambdas,
though I haven't tested this:

http://www.cs.uu.nl/wiki/Ehc/LanguageFeatures

"A History of Haskell":

http://research.microsoft.com/~simonpj/papers/history-of-haskell/index.htm

points to "A system of constructor classes"

http://web.cecs.pdx.edu/~mpj/pubs/fpca93.html
or
http://citeseer.ist.psu.edu/jones95system.html

regarding unification and type lambdas.

Jim