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

[Tino Calancha]

Andreas Röhler <andreas.roehler@easy-emacs.de> 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:

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>From 71da9ad4f6bbc307c5fb3f8bd0c6621312b2d4f4 Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
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
 
-- 
2.9.3

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In GNU Emacs 26.0.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.1)
 of 2016-10-12
Repository revision: 9640e9f4e95cd95c04875e90a4ff638e1e51f977