Suppose I have a module module Bounded(E: Set.OrderedType), and I want to use Set.Make(E) as a component of Bounded.t, like type t = { mutable data : Set.Make(struct type t = E.t let compare = compare end); }; Is there a way to do that?

Directly, no: the way to do this is to name a module that is the result of the functor application. Like this: module ESet = Set.Make (E) type t = { mutable data : ESet.t; } And if you need to write the signature of that module: module ESet : Set.S with type elt = E.t type t = { mutable dat…

Thanks, @gsg . I was a bit unclear. My problem is creating ESet within another functor. E.g., I would like to do something like this, but syntactically valid: module Bounded(E: Set.OrderedType) = struct let module SE = Set.Make(struct type t = E.t let compare = E.compare end) type t = { …

It’s very much the same for functors: module Bounded (E: Set.OrderedType) = struct module SE = Set.Make (E) type t = { bound : int ; mutable data : SE.t; } end A few things to note: let module M = ... is the syntax for local binding of modules. module M = ... defines an element with…

[image] gsg: Directly, no: the way to do this is to name a module that is the result of the functor application. To be pedant, it is in fact possible to access type components of a functor application inside a type definition. For instance, type t = { x : Set.Make(String).t } is valid. It i…

Using a Set in a module type

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coventry August 19, 2017, 10:19am 6

Thanks, gsg. That worked.

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Using a Set in a module type

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