RE: [External] : insert string at point with emacs-version

RE: [External] : insert string at point with emacs-version

[Drew Adams]

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> How can I have a condition that checks whether the version
> is 28.0 or later

(> emacs-major-version 27)


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insert string at point with emacs-version

[goncholden]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Tuesday, February 1st, 2022 at 5:54 PM, Drew Adams <drew.adams@oracle.com> wrote:

> How can I have a condition that checks whether the version
>
> is 28.0 or later

(> emacs-major-version 27)

My difficulty is about calling

(alist-get (frame--current-backround-mode nil) colors)

when (> emacs-version 28.0)

and do some other thing otherwise.

RE: [External] : insert string at point with emacs-version

[Drew Adams]

Ask Emacs:

`C-h f if'
`C-h f cond'
`C-h i', choose Elisp manual, `g Conditionals'

> My difficulty is about calling
> (alist-get (frame--current-backround-mode nil) colors)
> when (> emacs-version 28.0)
> and do some other thing otherwise.

RE: [External] : insert string at point with emacs-version

[Drew Adams]

> > `C-h f if'` C-h f cond'
> > `C-h i', choose Elisp manual,` g Conditionals'
> 
> Would the use of cond in the case below make sense?
> 
>   (let* ( (colors annotation-chroma)
>           (levels
> 	   (cond (>= emacs-version 28.0)
> 		 (alist-get (frame--current-backround-mode nil) colors)) ))

Pay attention to what `C-h f cond' tells you.

(cond ((>= emacs-version 28.0)
       (alist-get (frame--current-backround-mode nil) colors))

Typically you use `cond' with more than one
condition branch, and often with more than two.

The above code is the same as this:

(when (>= emacs-version 28.0)
  (alist-get (frame--current-backround-mode nil) colors))

or this:

(if (>= emacs-version 28.0)
    (alist-get (frame--current-backround-mode nil) colors))

Again, the Elisp manual, node Conditionals, tells
you these things.  Ask Emacs.

https://www.gnu.org/software/emacs/manual/html_node/elisp/Conditionals.html

Many people use `if' only with two branches, or
when the result matters.  Using `when' or `unless'
when the result isn't important makes that clear
to human readers.

When the result matters, you also have `and' and
`or', in addition to `if' and `cond'.

And know about `progn', to group multiple actions.