[m-dev.] subtypes proposal

[Julien Fischer]

On Fri, 16 Apr 2021, Peter Wang wrote:

> On Thu, 14 Jan 2021 12:55:39 +1100 Peter Wang <novalazy at gmail.com> wrote:
>> Hi,
>> 
>> In this proposal, subtypes are distinct d.u. types that share a data
>> representation with a base type, which is a normal d.u. type.
>> Subtypes of subtypes are allowed.
>> Every term of a given subtype must also be valid term in the supertype
>> (recursively, up to the base type), with the same data representation.
>> 
>> A subtype can be introduced like this:
>>
>>     :- type SUBTYPE =< SUPERTYPE
>>         --->    BODY.
>
> Subtypes are supported as of ROTD 2021-04-14.

You may want to add an annoucment for them on the webpage.

Julien.