Re: [Caml-list] Recursive fixed polymorphic variants

[Erkki Seppala <flux@modeemi.cs.tut.fi>]

Hello,

Jacques-Pascal Deplaix <jp.deplaix@gmail.com> writes:

> let rec f = function `B x -> f x | `A -> ();;

The problem is that 'f' has two final types in the same scope - or
that's the best way I can describe it, someone can maybe chime in
:). One way to solve it for this instance would be:

let rec f = function `B x -> g x | `A -> ()
and g = function `B x -> f x | `A -> ();;

# f (M.b (M.a ()))
- : unit = ()

This gives f (and g) the inferred type ([< `A | `B of [< `A | `B of 'a
] ] as 'a) -> unit.

I was under the impression I should be able to describe using the type
variable syntax in function type, but I was unable to.

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