sqlite library

sqlite library

[Ag Ibragimov]

I wrote a prototype of a package that queries a sqlite DB, but only
later realized that built-in support for it was added in Emacs 29 (the version
I use).
I want to make the package compatible with older versions of Emacs (at
least down to 27). I checked package repositories, it seems there are a
few packages out there (and I don't know which one to use).

What's the best and most straightforward option here for me?

Can you someone advise me what should I use, what should I put in
`Package-Requires:`; maybe the best would be to point to a simple
package with a similar problem?

If I use an external package anyway, does it make sense to check for the
availability of the built-in functions? Or I should somehow load the
external package only when it detects Emacs version prior to 29?

Thank you.

Re: sqlite library

[Eli Zaretskii]

> From: Ag Ibragimov <agzam.ibragimov@gmail.com>
> Date: Fri, 09 Dec 2022 18:35:07 -0600
> 
> I wrote a prototype of a package that queries a sqlite DB, but only
> later realized that built-in support for it was added in Emacs 29 (the version
> I use).
> I want to make the package compatible with older versions of Emacs (at
> least down to 27). I checked package repositories, it seems there are a
> few packages out there (and I don't know which one to use).
> 
> What's the best and most straightforward option here for me?

Use the function sqlite-available-p to find out whether the current
Emacs session has built-in support for SQLite.  If sqlite-available-p
is not fboundp, you know it's an Emacs version older than 29;
otherwise call it to see if it returns non-nil to see if SQLite
support was compiled in.

Re: sqlite library

[Daniel Kraus]

Hi!

Ag Ibragimov <agzam.ibragimov@gmail.com> writes:

> What's the best and most straightforward option here for me?
>
> Can you someone advise me what should I use, what should I put in
> `Package-Requires:`; maybe the best would be to point to a simple
> package with a similar problem?

I know forge uses a defcustom to decide which connector to use
with the `emacsql` package.

https://github.com/magit/forge/blob/3ab86bb44073e48ff7e6e432b6b4d2af12e45295/lisp/forge-db.el#L40-L63

Maybe this helps.
Cheers,
  Daniel

Re: sqlite library

[Stefan Monnier]

> Can you someone advise me what should I use, what should I put in
> `Package-Requires:`; maybe the best would be to point to a simple
> package with a similar problem?

See https://elpa.gnu.org/packages/triples.html

It does not announce any dependency in its `Package-Requires:` (other
than Emacs≥25 and `seq`).  Instead it checks at runtime whether/which
kind of sqlite support is available:

  (unless (pcase-exhaustive triples-sqlite-interface
              ('builtin
               (and (fboundp 'sqlite-available-p) (sqlite-available-p)))
              ('emacsql (require 'emacsql nil t)))
    (error "The triples package requires either Emacs 29 or the emacsql package to be installed."))

`Package-Requires:` is just a tool to help users install the package;
it doesn't have to be "exact".


        Stefan