[Haskell-cafe] Stateful DSLs

[Edward Z. Yang]

Excerpts from Günther Schmidt's message of Fri Sep 17 13:27:45 -0400 2010:
> I'd want to create a EDSL where I want to be able to statically ensure 
> that expressions can only be built according to a particular "state".
> 
> Like in a network application, SMTP client for example, where I can only 
> issue commands if the application is in a certain state.
> 
> Are there any Haskell examples for this sort of thing?

Hello Gunther,

I believe what you are describing is called "session types".  There
are several session type encodings on Hackage: sessions, simple-sessions
and full-sessions.  However, I don't think they're really ready to be used
on actual projects.

Cheers,
Edward