[m-rev.] for review: delete quotes from `VarNames' in stdlib comments

[Julien Fischer]

On Mon, 7 Mar 2022, Zoltan Somogyi wrote:

> Delete quotes from `VarNames' in stdlib comments.
> 
> In the Mercury standard library, every exported predicate or function
> has (or at least *should* have) a comment that documents it, including
> the meanings of its arguments. About 35-40% of these modules put `'s
> (left and right quotes) around the names of the variable representing
> those arguments. Some tried to do it consistently (though there were spots
> with unquoted or half quoted names), while some did it only a few places.
> This is inconsistent: we should either do it everywhere, or nowhere.
> This diff makes it nowhere, because
> 
> - this is what the majority of the standard library modules do;
> - this is what virtually all of the modules in the compiler, profiler,
>   deep_profiler etc directories do; and because
> - typing all those quotes when adding new predicates in modules that
>   follow this convention is a pain in the ass.
> 
> Likewise, the comment explaining a predicate often started with
>
>     % `predname(arguments)' returns ...
> 
> This diff deletes these quotes as well, since they add nothing useful.
> 
> This diff does leave in place quotes around code fragments, both terms
> and goals, where this helps delineate the boundaries of that fragment.

Another reason is that we are no longer using xterms in the 1990s and
with the fonts in modern terminals, `' looks non-symmetrical and weird.

> diff --git a/library/univ.m b/library/univ.m
> index e1d95468d..6ff9aab99 100644
> --- a/library/univ.m
> +++ b/library/univ.m
> @@ -10,7 +10,7 @@
>  % Main author: fjh.
>  % Stability: medium.
>  %
> -% The universal type `univ'
> +% The universal type `univ',

Perhaps,

     The universial type: univ.

?

I suggest also updating the "Standard library predicates" section of
the coding standard to document the quoting convention for comments
in the standard library.

The diff looks fine otherwise.

Julien.