diff options
Diffstat (limited to 'lisp/emacs-lisp')
| -rw-r--r-- | lisp/emacs-lisp/seq.el | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index 0d9483aecb6..1b8d86563a1 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -168,21 +168,25 @@ if positive or too small if negative)." ((or (stringp sequence) (vectorp sequence)) (substring sequence start end)) ((listp sequence) (let (len - (errtext (format "Bad bounding indices: %s, %s" start end))) + (orig-start start) + (orig-end end)) (and end (< end 0) (setq end (+ end (setq len (length sequence))))) (if (< start 0) (setq start (+ start (or len (setq len (length sequence)))))) (unless (>= start 0) - (error "%s" errtext)) + (error "Start index out of bounds: %s" orig-start)) (when (> start 0) (setq sequence (nthcdr (1- start) sequence)) - (or sequence (error "%s" errtext)) + (unless sequence + (error "Start index out of bounds: %s" orig-start)) (setq sequence (cdr sequence))) (if end - (let ((res nil)) - (while (and (>= (setq end (1- end)) start) sequence) - (push (pop sequence) res)) - (or (= (1+ end) start) (error "%s" errtext)) - (nreverse res)) + (let ((n (- end start))) + (when (or (< n 0) + (if len + (> end len) + (and (> n 0) (null (nthcdr (1- n) sequence))))) + (error "End index out of bounds: %s" orig-end)) + (take n sequence)) (copy-sequence sequence)))) (t (error "Unsupported sequence: %s" sequence)))) |