[Haskell-cafe] Re: Finally tagless and ghc-extensions

oleg at okmij.org oleg at okmij.org
Fri Oct 30 03:32:27 EDT 2009

> In both, the JFP & APLAS paper, the authors note that no fancy type
> extension are needed for this approach. But in almost every (Haskell)
> example that is a bit more involved the authors do make use of
> functional dependencies and / or type families. GADTs are also being
> used, although *not* in the syntax definition...

Just to dispel the doubts, here is the Haskell98 version of the
previously posted code CB.hs (tagless final interpreter for
call-by-name, call-by-value and call-by-need lambda-calculus with
integers and constants)

It may appear somewhat less convenient. How less convenient -- well,
you decide.

The code can be easily re-written in OCaml, which has no typeclasses,
type families and other bleeding edge features. Talking about it
here is probably not appropriate. (I wonder if someone has ever
cross-posted to the Haskell and Caml lists).

> I'm still digesting the "Finally Tagless" approach from Oleg, Jacques
> and Chen.
You probably mean Chung-chieh Shan, whose last name is Shan and the
first name is Chung-chieh.

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