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Re: polymorphic recursion
- Pierre Weis
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Date: | 1998-09-22 (16:37) |
From: | Pierre Weis <Pierre.Weis@i...> |
Subject: | Re: polymorphic recursion |
> right, but there is no polymorphic recursion in Ocaml, is there? As mentioned earlier there is some form of polymorphic recursion in objects. A (limited form of) polymorphic recursion could be added to the core language in the future if we find a simple way to do so. > > We may need explicit Forall keywords to express type schemes in constraints. > > Indeed, this is a problem. Standard ML solves this by defining some > explicit rules for free type variables (section 4.6 of the definition - > p18). As far as I know this rules do not allow the simple expression of polymorphic type scheme in type constraints, since you have to figure out which type variables are quantified and where they are bound (as far as I remember this quantification implicitely occurs at the outermost level of the construct where the type variable appears ?). Explicit quantification would be simple and more explicit. Pierre Weis INRIA, Projet Cristal, Pierre.Weis@inria.fr, http://cristal.inria.fr/~weis/