Subject: bug#24627: 24.5; (thing-at-point 'list) may return a non-empty string without a list

From: Andreas Röhler <[email-masked]>
Date: Tue, 11 Oct 2016 20:40:12 +0200

On 11.10.2016 18:29, Tino Calancha wrote:
> Andreas Röhler <[email-masked]> writes:
>
>> With
>>
>> (defun foo ())
>>
>> at first open paren
>>
>> M-: (thing-at-point 'list t) RET
>>
>> returns the whole thing, right.
>>
>> But at second open paren returns the whole function too - where it
>> should return the empty arg-list
> Following patch do the right thing in my example and your example.
> Feel free to check it with some other examples that you may have:
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>  From dc2703a43a7b5dae60f7e88805971472253d4600 Mon Sep 17 00:00:00 2001
> From: Tino Calancha <[email-masked]>
> Date: Wed, 12 Oct 2016 01:16:52 +0900
> Subject: [PATCH] (thing-at-point 'list) return nil if no list at point
>
> * lisp/thingatpt.el (thing-at-point-bounds-of-list-at-point):
> Check first if we are at the beginning of a top-level sexp (Bug#24627).
> Escape '[' and ']' in doc string.
> ---
>   lisp/thingatpt.el | 22 +++++++++-------------
>   1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/lisp/thingatpt.el b/lisp/thingatpt.el
> index 6d1014b..acacff2 100644
> --- a/lisp/thingatpt.el
> +++ b/lisp/thingatpt.el
> @@ -219,22 +219,18 @@ 'beginning-of-sexp
>   
>   (defun thing-at-point-bounds-of-list-at-point ()
>     "Return the bounds of the list at point.
> -[Internal function used by `bounds-of-thing-at-point'.]"
> +\[Internal function used by `bounds-of-thing-at-point'.\]"
>     (save-excursion
>       (let ((opoint (point))
> -	  (beg (ignore-errors
> -		 (up-list -1)
> -		 (point))))
> +          (beg (if (looking-at-p "(")
> +                   (point)
> +                 (ignore-errors
> +                   (up-list -1)
> +                   (point)))))
>         (ignore-errors
> -	(if beg
> -	    (progn (forward-sexp)
> -		   (cons beg (point)))
> -	  ;; Are we are at the beginning of a top-level sexp?
> -	  (forward-sexp)
> -	  (let ((end (point)))
> -	    (backward-sexp)
> -	    (if (>= opoint (point))
> -		(cons opoint end))))))))
> +        (when beg
> +          (forward-sexp)
> +          (cons beg (point)))))))
>   
>   ;; Defuns
>   

Hmm, what if cursor is inside a string or comment?

BTW "list" might be more universal if understood syntactically
What about writing

(eq 4 (car (syntax-after (point))))