Re: version> and version>=

[goncholden]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Wednesday, February 2nd, 2022 at 3:00 PM, Yuri Khan <yuri.v.khan@gmail.com> 
wrote:

> On Wed, 2 Feb 2022 at 17:21, goncholden goncholden@protonmail.com wrote:
>
> > > What is the best way to check the version
> > >
> > > (if (version< emacs-version "28.0")
> > >
> > > or
> > >
> > > (< emacs-version 28.0)
>
> A typical case of the XY Problem. You want to solve X, you think Y
>
> will help you, and you ask how to do Y. You will get helpful comments
>
> on how to do Y, but miss out on all the better ways to do X.
>
> > Am working on colouring comments according to whether the background is 
> > light or dark.
>
> This is your original X. The solution to that is to look at
>
> (frame-parameter nil 'background-mode), as told in the other thread.
>
> > (frame--current-backround-mode nil)
>
> This is your assumed solution, Y.
>
> In fact, you have another case of XY here. You discover
> ‘frame--current-background-mode’ is not available in Emacs < 28. Your
> actual problem is “how do I know a function is available in my Emacs”.
>
> You assume you need to check the Emacs version, but in fact you should
> check for features, not versions. (fboundp
> 'frame--current-background-mode) will return t if the function is
> available, nil if not.

Correct, the availability problem winded me up a little bit.