Henning Thielemann <[EMAIL PROTECTED]> wrote in article <[EMAIL PROTECTED]> in
gmane.comp.lang.haskell.cafe:
> It seems to become a FAQ. I think all DSLs suffer from the same problems:
> sharing and recursion. I've used wrappers for CSound, SuperCollider,
> MetaPost, they all have these problems.
What do you mean by the "recursion" problem?
Sometimes (or perhaps even often), sharing in an EDSL can be expressed
in two ways. First, to reuse a -value- in the embedded language, you
could introduce a "let" construct in the embedded language.
let_ expr body = body expr
Second, to reuse an -expression- in the embedded language, if your
interpreter is compositional (here by "interpreter" I include a
compiler, and by "compositional" I mean a fold), then you can represent
an embedded expression simply as its interpretation.
add x y = x + y
let expr = add x y in add expr expr
Jacques Carette, Oleg Kiselyov, and I have been exploring this "final"
representation. http://okmij.org/ftp/Computation/tagless-typed.html
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