You can't do it for object types directly, but you can do it for class types:

class type t1 = object method f : int end

class type t2 = object inherit t1 method g : bool end

Defining a class type also defines the corresponding object type, which means the above results in types called t1 and t2 that are equal to the ones you want.

This trick also lets you use #t2 to refer to the polymorphic type < f : int; g : bool; .. >.

Regards,

Leo

On Thu, 9 Feb 2017, at 11:15 PM, Steffen Smolka wrote:

Is there syntax to conveniently extend object types?

Concretely, for types

type t1 = < f : int >

type t2 = < f : int; g : bool >

I would like a syntax that allows me to define t2 in terms of t1.

Thanks!

-- Steffen