[m-dev.] documenting typed insts

[Julien Fischer]

On Tue, 7 Jan 2020, Zoltan Somogyi wrote:

>
>
> On Tue, 7 Jan 2020 19:48:31 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
>> 3. Since the intention is that insts will eventually be required to
>> be typed, documenting the syntax etc. would allow users to begin making
>> that transition now.
>>
>> Is there any documentation for this feature about?
>
> No. The commit message says:
>
>    There is no documentation of the new language extension yet, since it is
>    not yet really useful. That would come later, when we check that an inst
>    specified as for being for a specific type is used only on values
>    of that type. We would also need to resolve the two issues marked with
>    "XXX IFTC" in the diff.

Is that not done?  If I do

     :- type tm ---> walking ; cycling ; car.
     :- type fruit ---> lemon ; orange ;  apple.
     :- inst citrus for fruit/0 ---> lemon ; walking.

I get an error about the inst defintion.

    foo.m:010: Error: inst `citrus'/0 is declared to be for type `foo.fruit'/0, but
    foo.m:010:   its top level function symbol `walking'/0 is not a function symbol
    foo.m:010:   of that type.

Or is the commit message referring to something else?

Julien.