Re: Add seq-shuffle

[Adam Porter <adam@alphapapa.net>]

On 9/15/24 01:27, Eli Zaretskii wrote:
>> Date: Sat, 14 Sep 2024 20:44:16 -0500
>> Cc: Emacs-devel@gnu.org
>> From: Adam Porter <adam@alphapapa.net>
>>
>> Thanks, this is a gap in functionality that should be filled.
> 
> Not every gap _should_ be filled, no.  Only those we think (and have
> some basis to think) it is going to be missed by enough real-life Lisp
> programs.
> 
> So saying "should be filled" without explaining why you think it
> should be filled is less convincing than it could have been.  Thus, I
> urge you to add motivation for your opinion.  TIA.

I think it should be filled because it's not an uncommon thing to want 
to do (e.g. it's needed in Listen.el and Elfeed), and it's not obvious 
how to do it from scratch, especially in a performant way.  A "naive" 
implementation, without regard for performance, can perform quite poorly.

That there are different sequence types, each with their own 
characteristics, further complicates the matter.  For newer Elisp 
programmers, who may be unfamiliar with the various types and 
performance issues in Elisp, having a built-in function to do it 
correctly and quickly would be helpful.

As it is, we have had various implementations in various third-party 
libraries for years, each with the same purpose but doing it slightly 
differently.  As an example from other languages, Python provides the 
random.shuffle function for sequences.  It would seem natural for 
Emacs's seq library to provide a similar function.

It's not a big deal, but if I had a vote, it would be to include such a 
function in seq.el.

--Adam