Dear Kenichi,

No, this is currently not supported. For this use-case you will have to use
modules, typically a functor (in some circumstances a first-class module
parameter may work as well, if the return type does not depend on the
parameter).

On Sat, Apr 18, 2020 at 4:24 AM Kenichi Asai <asai@is.ocha.ac.jp> wrote:

> OCaml allows locally abstract types:
>
> let f (type t) x = ...
>
> Can the t take parameters as in 'a t?  I want to have a locally
> abstract type that has type parameters.  The manual says the t in
> (type t) must be {typeconstr-name}+ which expands to a sequence of
> lowercase-ident, so probably this is not allowed...
>
> --
> Kenichi Asai
>