[m-rev.] for post-commit review: improve documentation of query options

[Julien Fischer]

Hi Zoltan,

On Sat, 15 Jan 2022, Zoltan Somogyi wrote:

> On Sat, 15 Jan 2022 00:38:09 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
>>>> I just had a grep
>>>> through the G12 source code which is using them all over the place.
>>>
>>> Using them for what purpose, if I may ask?
>>
>> Their intended purpose: controlling what set of grades a library is
>> installed in.
>
> Sorry for harping on about this, but I still have questions.
>
> - What library is this sentence talking about? Is it the Mercury
>  standard library, or some other?

The G12 libraries.

> - How does setting setting up the value of an accumulating option
>   *control* anything? What code uses the value of the option
>  to decide in what grades to install anything? The output of
>  "egrep -w libgrades" did not reveal any such code to me.

Is egrep broken on your system? ;-)  It told me exactly what
code is doing that:

make.program_target.m: globals.lookup_accumulating_option(Globals, libgrades, LibGrades0),

(In the aptly named install_library predicate.)

Julien.