Re: Instead of pcase

[João Távora]

On Fri, Dec 1, 2023 at 8:10 AM Eli Zaretskii <eliz@gnu.org> wrote:

> Exactly my point: these periods and other special characters are
> "magic" in pcase, but not elsewhere in Lisp.  Sometimes they are just
> for better readability, sometimes they are significant in other ways.

What you're saying isn't correct, Eli.  That period you are pointing to
has _exactly_ the same magic "elsewhere in Lisp" as it does in "pcase".

Forget pcase for a minute.  "Elsewhere in Lisp", if all those 5 symbols
are bound, then your example (now corrected):

  `(,hookfun . (,start ,end ,collection . ,plist))

produces a list made up with four cons cells.

If you take out the periods:

  `(,hookfun (,start ,end ,collection ,plist))

This still produces a list, but now it's made up of six cons cells!
That's a world of difference.

In a different email, I've explained how, both in 'pcase' and "elsewhere
in Lisp", your example can be rewritten with one less period to still use
four cons cells exactly.

João