[Haskell-cafe] Re: Map constructor in a DSL
corentin.dupont at gmail.com
Thu Oct 28 06:09:05 EDT 2010
Thank you for your rich responses.
Indeed I think I miss some thinks in my DSL, that would make things easier
to deal with lists and first class functions.
I don't really know what for now.
Perhaps a List Constructor? Or a constructor on functions like yours Ryan?
EAp :: Exp ref (a -> b) -> Exp ref a -> Exp ref b
It's from which DSL? It is accessible on the net?
Chris suggested me that I can only define the Foldr constructor and deduce
Map from it.
But maybe I have to add a List constructor for that.
But in the suggestions from Ryan and Brandon I don't understand why I should
add an extra type parameter and what it is!
Steffen: Wow nice. I'll integrate that ;)
I'm also looking at the Atom's DSL to get inspiration.
Something I don't understand in it is that it has two languages, on typed:
data E a where
VRef :: V a -> E a
Const :: a -> E a
Cast :: (NumE a, NumE b) => E a -> E b
Add :: NumE a => E a -> E a -> E a
And, along with it, an untyped counterpart:
-- | An untyped term.
= UVRef UV
| UConst Const
| UCast Type UE
| UAdd UE UE
What that for? What's the use of having beautiful GADT if you have to
maintain an untyped ADT aside??
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