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From: =?utf-8?Q?Dagfinn_Ilmari_Manns=C3=A5ker?= <ilmari@ilmari.org>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,  Andrew Dunstan <andrew@dunslane.net>,
  Robert Haas <robertmhaas@gmail.com>,  "pgsql-hackers@postgresql.org"
 <pgsql-hackers@postgresql.org>
Subject: Re: documentation structure
References: <CA+TgmoZ2F+K0j=6BOJLD=YfpJMdJRXC7sWmtXGRjx1Rq0x8PUA@mail.gmail.com>
	<CAD5tBcJUVQu=9zpr9C+Z=3SjxrECURtr_i1oipMqke4dpZXtyQ@mail.gmail.com>
	<20240416182310.2j6g5fqqcwi4s6wm@awork3.anarazel.de>
	<1355791.1713294332@sss.pgh.pa.us>
	<20240416201700.wyz7ojp3fr7222xt@awork3.anarazel.de>
Date: Wed, 17 Apr 2024 12:07:24 +0100
In-Reply-To: <20240416201700.wyz7ojp3fr7222xt@awork3.anarazel.de> (Andres
	Freund's message of "Tue, 16 Apr 2024 13:17:00 -0700")
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Andres Freund <andres@anarazel.de> writes:

> Definitely shouldn't be the same in all cases, but I think there's a decent
> number of cases where they can be the same. The differences between the two is
> often minimal today.
>
> Entirely randomly chosen example:
>
> { oid => '2825',
>   descr => 'slope of the least-squares-fit linear equation determined by the (X, Y) pairs',
>   proname => 'regr_slope', prokind => 'a', proisstrict => 'f',
>   prorettype => 'float8', proargtypes => 'float8 float8',
>   prosrc => 'aggregate_dummy' },
>
> and
>
>       <row>
>        <entry role="func_table_entry"><para role="func_signature">
>         <indexterm>
>          <primary>regression slope</primary>
>         </indexterm>
>         <indexterm>
>          <primary>regr_slope</primary>
>         </indexterm>
>         <function>regr_slope</function> ( <parameter>Y</parameter> <type>double precision</type>, <parameter>X</parameter> <type>double precision</type> )
>         <returnvalue>double precision</returnvalue>
>        </para>
>        <para>
>         Computes the slope of the least-squares-fit linear equation determined
>         by the (<parameter>X</parameter>, <parameter>Y</parameter>)
>         pairs.
>        </para></entry>
>        <entry>Yes</entry>
>       </row>
>
>
> The description is quite similar, the pg_proc entry lacks argument names. 
>
>
>> This sounds to me like it would be a painful exercise with not a
>> lot of benefit in the end.
>
> I think the manual work for writing signatures in sgml is not insignificant,
> nor is the volume of sgml for them. Manually maintaining the signatures makes
> it impractical to significantly improve the presentation - which I don't think
> is all that great today.

And it's very inconsistent.  For example, some functions use <optional>
tags for optional parameters, others use square brackets, and some use
<literal>VARIADIC</literal> to indicate variadic parameters, others use
ellipses (sometimes in <optional> tags or brackets).

> And the lack of argument names in the pg_proc entries is occasionally fairly
> annoying, because a \df+ doesn't provide enough information to use functions.

I was also annoyed by this the other day (specifically wrt. the boolean
arguments to pg_ls_dir), and started whipping up a Perl script to parse
func.sgml and generate missing proargnames values for pg_proc.dat, which
is how I discovered the above.  The script currently has a pile of hacky
regexes to cope with that, so I'd be happy to submit a doc patch to turn
it into actual markup to get rid of that, if people think that's a
worhtwhile use of time and won't clash with any other plans for the
documentation.

> It'd also be quite useful if clients could render more of the documentation
> for functions. People are used to language servers providing full
> documentation for functions etc...

A more user-friendly version of \df+ (maybe spelled \hf, for symmetry
with \h for commands?) would certainly be nice.

> Greetings,
>
> Andres Freund

- ilmari