diff options
Diffstat (limited to 'lisp/emacs-lisp/seq.el')
| -rw-r--r-- | lisp/emacs-lisp/seq.el | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index 918b0dcd390..9a5872c094b 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -57,7 +57,6 @@ ;;; Code: (eval-when-compile (require 'cl-generic)) -(require 'cl-lib) ;; for cl-subseq (defmacro seq-doseq (spec &rest body) "Loop over a sequence. @@ -151,7 +150,27 @@ If END is omitted, it defaults to the length of the sequence. If START or END is negative, it counts from the end. Signal an error if START or END are outside of the sequence (i.e too large if positive or too small if negative)." - (cl-subseq sequence start end)) + (cond + ((or (stringp sequence) (vectorp sequence)) (substring sequence start end)) + ((listp sequence) + (let (len + (errtext (format "Bad bounding indices: %s, %s" start 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)) + (when (> start 0) + (setq sequence (nthcdr (1- start) sequence)) + (or sequence (error "%s" errtext)) + (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)) + (copy-sequence sequence)))) + (t (error "Unsupported sequence: %s" sequence)))) (cl-defgeneric seq-map (function sequence) |