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| author | Lars Ingebrigtsen <larsi@gnus.org> | 2022-08-09 19:18:55 +0200 |
|---|---|---|
| committer | Lars Ingebrigtsen <larsi@gnus.org> | 2022-08-09 19:21:36 +0200 |
| commit | 5269842833471c960352ced3c60ce2329660b8cf (patch) | |
| tree | 714d09b0548bc57c2f5b7d0a8d492cea452cafcc | |
| parent | b92e88875802724af9e08201ea65a96dd5f20ff1 (diff) | |
| download | emacs-5269842833471c960352ced3c60ce2329660b8cf.tar.gz | |
Add a faster seq-uniq for lists
* lisp/emacs-lisp/seq.el (seq-uniq): Add a faster method for lists
(bug#57079).
| -rw-r--r-- | lisp/emacs-lisp/seq.el | 17 | ||||
| -rw-r--r-- | test/lisp/emacs-lisp/seq-tests.el | 13 |
2 files changed, 30 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index 1b8d86563a1..6ddd8de6e8d 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -455,6 +455,23 @@ TESTFN is used to compare elements, or `equal' if TESTFN is nil." (setq result (cons elt result)))) (nreverse result))) +(cl-defmethod seq-uniq ((sequence list) &optional testfn) + (let ((result nil)) + (if (not testfn) + ;; Fast path. + (while sequence + (unless (member (car sequence) result) + (push (car sequence) result)) + (pop sequence)) + ;; Slower path. + (while sequence + (unless (seq-find (lambda (elem) + (funcall testfn elem (car sequence))) + result) + (push (car sequence) result)) + (pop sequence))) + (nreverse result))) + (cl-defgeneric seq-mapcat (function sequence &optional type) "Concatenate the result of applying FUNCTION to each element of SEQUENCE. The result is a sequence of type TYPE, or a list if TYPE is nil." diff --git a/test/lisp/emacs-lisp/seq-tests.el b/test/lisp/emacs-lisp/seq-tests.el index 3b22e42df24..a655377e6cc 100644 --- a/test/lisp/emacs-lisp/seq-tests.el +++ b/test/lisp/emacs-lisp/seq-tests.el @@ -559,5 +559,18 @@ Evaluate BODY for each created sequence. (should (equal (seq-split seq 3) '("012" "345" "678" "9"))))) +(ert-deftest test-seq-uniq-list () + (let ((list '(1 2 3))) + (should (equal (seq-uniq (append list list)) '(1 2 3)))) + (let ((list '(1 2 3 2 1))) + (should (equal (seq-uniq list) '(1 2 3)))) + (let ((list (list (substring "1") + (substring "2") + (substring "3") + (substring "2") + (substring "1")))) + (should (equal (seq-uniq list) '("1" "2" "3"))) + (should (equal (seq-uniq list #'eq) '("1" "2" "3" "2" "1"))))) + (provide 'seq-tests) ;;; seq-tests.el ends here |