Feature request: Easy customisation of sql-mode product keywords

Feature request: Easy customisation of sql-mode product keywords

[Nik Clayton]

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Hi, I've got a feature request for sql-mode.

[not 100% certain if this list was better than bug-gnu-emacs, but
https://www.emacswiki.org/emacs/MichaelMauger mentioned monitoring this
list, so I figured it was a better fit]

I'd like to be able to easily either:

1. Configure the mode to only recongnise keywords in uppercase, or
2. Customise the keywords associated with an SQL product in sql-mode.

The specific problem I have, and why this would solve it is as follows.

I produce some teaching material using Emacs and org-mode, exporting the
results to HTML. This uses the syntax highlighting in Emacs to generate
syntax highlighted SQL in the slides and course notes.

However, given a query like the following:

  SELECT name
    FROM track
   WHERE trackid = 1222;

the "name" on the first line is highlighted as a keyword. Because it is, it
shows up in sql-mode-ansi-font-lock-keywords.

However, this means that it's rendered differently to "track" snd "trackid
= 1222;" in that example.

This is not easy behaviour to customise in my Emacs configuration (as far
as I can tell), for a few reasons.

The most important is that the code that creates
sql-mode-ansi-font-lock-keywords runs under eval-when-compile -- it's not a
function that I can call again after making some modifications, or provide
advice around to customise the behaviour.

Similarly, this means that I can't advise sql-font-lock-keywords-builder,
and change its arguments so that it only receives upper-case keywords -- by
the time my code runs its too late.

The actual list of keywords in sql.el aren't bound to a list, only the
resulting regexp is. Which means I can't take that list, modify it, and
create a new value for sql-mode-ansi-font-lock-keywords

So I resorted to this:

(setf (car (car sql-mode-ansi-font-lock-keywords))
      (s-replace "n\\(?:ame\\|u\\(?:llable\\|mber\\)\\))"
                 "nu\\(?:llable\\|mber\\))"
                 (car (car sql-mode-ansi-font-lock-keywords))))

Best, N

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Feature request: Easy customisation of sql-mode product keywords

[Michael Mauger]

On Tue, 7 May 2019 19:33:59 +0200, Nic Clayton said:
> Hi, I've got a feature request for sql-mode.
>
> [not 100% certain if this list was better than bug-gnu-emacs, but
> https://www.emacswiki.org/emacs/MichaelMauger mentioned monitoring this
> list, so I figured it was a better fit]>

Sorry for the delay in responding-- I've been laid up for a while...

> I'd like to be able to easily either:
>
> 1. Configure the mode to only recongnise keywords in uppercase, or
> 2. Customise the keywords associated with an SQL product in sql-mode.
>
> ...
>
>  SELECT name
>    FROM track
>   WHERE trackid = 1222;
>
> the "name" on the first line is highlighted as a keyword. Because it is, it
> shows up in sql-mode-ansi-font-lock-keywords.
>

There are two ways to alter the keyword locking in your case:

1) Set `sql-mode-ansi-font-lock-keywords` to nil and rely upon only on the
dialect keywords

    (setq sql-mode-ansi-font-lock-keywords nil)

2) Add keyword matching rules that override the default settings so that you get
highlighting that you want.

    (sql-add-product-keywords 'mysql
      (cons
        (regexp-opt '("name" "table_name" "index_name" "constraint_name")
                    'symbols)
        '(quote default)))       

I am looking to add more sophisticated font locking to sql-mode to avoid
highlighting keywords in places where the syntax isn't looking for one.

>
> Best, N

Hopefully this helps. Happy Hacking!

--
MICHAEL@MAUGER.COM // FSF and EFF member // GNU Emacs sql.el maintainer