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

From: Andreas Röhler <[email-masked]>
Date: Wed, 12 Oct 2016 09:10:42 +0200

On 12.10.2016 06:58, Tino Calancha wrote:
> Andreas Röhler <[email-masked]> writes:
>
>> Hmm, what if cursor is inside a string or comment?
> The list will be returned anyway as thingatpt always does.
> AFAICT, skipping lists inside comments/strings would be a new feature
> for this lib: better request that in a separated bug report.
>
>
>> BTW "list" might be more universal if understood syntactically
>> What about writing
>>
>> (eq 4 (car (syntax-after (point))))
> Agreed.  Thank you!
> Here is the new patch:
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>  From 71da9ad4f6bbc307c5fb3f8bd0c6621312b2d4f4 Mon Sep 17 00:00:00 2001
> From: Tino Calancha <[email-masked]>
> Date: Wed, 12 Oct 2016 13:49:32 +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 '[' 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..421dcde 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 (eq 4 (car (syntax-after (point))))
> +                   (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
>   

beg still needs a check like

(not (nth 8 (parse-partial-sexp (point-min) (point))))

otherwise it could match inside a string or comment