Sv: Suggestion: two new commands: beginning-of-list and end-of-list

[arthur miller]

>> but actually not the one that places the cursor at the beginning of a list.

>

>I think we do have it: C-M-u, backward-up-list.  What's more, it works

>not only in Lisp.  I use it all the time.

Yes you have. It works slightly differently when you are in a string, and it

places cursor before the opening parenthesis, not after.

>So I wonder why we need another function that does basically the same.

I think it makes sense to keep backward-up-list as it is, since it handles

literal strings as it does. But the behaviour is controlled via special vars

esape-strings and no-syntax-crossing. If we want similar command as

beginning-of-string, we have to wrap it and let-bind those variables to

change how it works.

I am not sure, what is a symmetric function to move cursor to the end of list?

But as said in the previous mail: this function is *already* in Emacs, so it is

already taking the memory in the process.  It is just not used more than

once, and have *potential* to be used more. In other words, I suggest these

two functions as a convenience, not because it is impossible to do something

similar via some combination of other commands and variables.

By the way, why did all occasions of the word "_expression_" ended up surroneded

with underscores in the online archive?

---

Från: Eli Zaretskii <eliz@gnu.org>
Skickat: den 9 september 2024 21:11
Till: arthur miller <arthur.miller@live.com>
Kopia: emacs-devel@gnu.org <emacs-devel@gnu.org>
Ämne: Re: Suggestion: two new commands: beginning-of-list and end-of-list

 

> From: arthur miller <arthur.miller@live.com>
> Date: Mon, 9 Sep 2024 18:32:33 +0000
>
> In elisp-mode.el, there is a function, IMO somewhat unfortunately named
> "elisp--beginning-of-sexp".  What this function does is to place cursor at the
> beginning of the innermost list, which we can perhaps call more conveniently,
> "current list".
>
> The function does so always, and is relatively well written, minor the case when
> the cursor is placed in a literal string or outside a symbolic _expression_, say
> between two top-level forms. In those cases, it jumps into the first string
> before the current string, which might be anywhere in the file prior to the
> current string, or to the beginning of the file.
>
> I took me a liberty to rename this function and update the doc to a more
> appropriate wording, and turn it into a command. I have also patched the
> above mentioned cases when it is invoked in a literal string or outside of
>  an _expression_.
>
> As another consideration, I have moved this function into lisp.el (in
> lisp/emacs-lisp/) in the sources.  It does not look like it has nothing
> particularly specific to EmacsLisp per se, seems like it should work on any
> "parenthesis"-language. I have tested it successfully in both CommonLisp and
> EmacsLisp files.
>
> I found only one user of elisp--beginning-of-sexp in the entire Emacs, and that
> is the function directly above: elisp--fnsym-in-current-sexp.
>
> Emacs already has few functions for motion over lists and symbolic expressions,
> but actually not the one that places the cursor at the beginning of a list.

I think we do have it: C-M-u, backward-up-list.  What's more, it works
not only in Lisp.  I use it all the time.

So I wonder why we need another function that does basically the same.

Thanks.