diff options
Diffstat (limited to 'lisp/emacs-lisp/seq.el')
| -rw-r--r-- | lisp/emacs-lisp/seq.el | 69 |
1 files changed, 44 insertions, 25 deletions
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index b6f0f66e5b1..82ade0ac0c3 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -347,6 +347,20 @@ list." sequence)) ;;;###autoload +(cl-defgeneric seq-remove-at-position (sequence n) + "Return a copy of SEQUENCE where the element at N got removed. + +N is the (zero-based) index of the element that should not be in +the result. + +The result is a sequence of the same type as SEQUENCE." + (seq-concatenate + (let ((type (type-of sequence))) + (if (eq type 'cons) 'list type)) + (seq-subseq sequence 0 n) + (seq-subseq sequence (1+ n)))) + +;;;###autoload (cl-defgeneric seq-reduce (function sequence initial-value) "Reduce the function FUNCTION across SEQUENCE, starting with INITIAL-VALUE. @@ -409,7 +423,7 @@ found or not." (cl-defgeneric seq-contains (sequence elt &optional testfn) "Return the first element in SEQUENCE that is equal to ELT. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (declare (obsolete seq-contains-p "27.1")) (seq-some (lambda (e) (when (funcall (or testfn #'equal) elt e) @@ -418,7 +432,7 @@ Equality is defined by TESTFN if non-nil or by `equal' if nil." (cl-defgeneric seq-contains-p (sequence elt &optional testfn) "Return non-nil if SEQUENCE contains an element equal to ELT. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (catch 'seq--break (seq-doseq (e sequence) (let ((r (funcall (or testfn #'equal) e elt))) @@ -429,14 +443,14 @@ Equality is defined by TESTFN if non-nil or by `equal' if nil." (cl-defgeneric seq-set-equal-p (sequence1 sequence2 &optional testfn) "Return non-nil if SEQUENCE1 and SEQUENCE2 contain the same elements. This does not depend on the order of the elements. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (and (seq-every-p (lambda (item1) (seq-contains-p sequence2 item1 testfn)) sequence1) (seq-every-p (lambda (item2) (seq-contains-p sequence1 item2 testfn)) sequence2))) ;;;###autoload (cl-defgeneric seq-position (sequence elt &optional testfn) - "Return the index of the first element in SEQUENCE that is equal to ELT. -Equality is defined by TESTFN if non-nil or by `equal' if nil." + "Return the (zero-based) index of the first element in SEQUENCE equal to ELT. +Equality is defined by the function TESTFN, which defaults to `equal'." (let ((index 0)) (catch 'seq--break (seq-doseq (e sequence) @@ -446,6 +460,23 @@ Equality is defined by TESTFN if non-nil or by `equal' if nil." nil))) ;;;###autoload +(cl-defgeneric seq-positions (sequence elt &optional testfn) + "Return indices for which (TESTFN (seq-elt SEQUENCE index) ELT) is non-nil. + +TESTFN is a two-argument function which is passed each element of +SEQUENCE as first argument and ELT as second. TESTFN defaults to +`equal'. + +The result is a list of (zero-based) indices." + (let ((result '())) + (seq-do-indexed + (lambda (e index) + (when (funcall (or testfn #'equal) e elt) + (push index result))) + sequence) + (nreverse result))) + +;;;###autoload (cl-defgeneric seq-uniq (sequence &optional testfn) "Return a list of the elements of SEQUENCE with duplicates removed. TESTFN is used to compare elements, or `equal' if TESTFN is nil." @@ -502,7 +533,7 @@ negative integer or 0, nil is returned." ;;;###autoload (cl-defgeneric seq-union (sequence1 sequence2 &optional testfn) "Return a list of all elements that appear in either SEQUENCE1 or SEQUENCE2. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (let* ((accum (lambda (acc elt) (if (seq-contains-p acc elt testfn) acc @@ -514,7 +545,7 @@ Equality is defined by TESTFN if non-nil or by `equal' if nil." ;;;###autoload (cl-defgeneric seq-intersection (sequence1 sequence2 &optional testfn) "Return a list of the elements that appear in both SEQUENCE1 and SEQUENCE2. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (seq-reduce (lambda (acc elt) (if (seq-contains-p sequence2 elt testfn) (cons elt acc) @@ -524,7 +555,7 @@ Equality is defined by TESTFN if non-nil or by `equal' if nil." (cl-defgeneric seq-difference (sequence1 sequence2 &optional testfn) "Return a list of the elements that appear in SEQUENCE1 but not in SEQUENCE2. -Equality is defined by TESTFN if non-nil or by `equal' if nil." +Equality is defined by the function TESTFN, which defaults to `equal'." (seq-reduce (lambda (acc elt) (if (seq-contains-p sequence2 elt testfn) acc @@ -618,13 +649,7 @@ Signal an error if SEQUENCE is empty." (cl-defmethod seq-take ((list list) n) "Optimized implementation of `seq-take' for lists." - (if (eval-when-compile (fboundp 'take)) - (take n list) - (let ((result '())) - (while (and list (> n 0)) - (setq n (1- n)) - (push (pop list) result)) - (nreverse result)))) + (take n list)) (cl-defmethod seq-drop-while (pred (list list)) "Optimized implementation of `seq-drop-while' for lists." @@ -655,16 +680,6 @@ Signal an error if SEQUENCE is empty." sequence (concat sequence))) -(defun seq--activate-font-lock-keywords () - "Activate font-lock keywords for some symbols defined in seq." - (font-lock-add-keywords 'emacs-lisp-mode - '("\\<seq-doseq\\>" "\\<seq-let\\>"))) - -(unless (fboundp 'elisp--font-lock-flush-elisp-buffers) - ;; In Emacsā„25, (via elisp--font-lock-flush-elisp-buffers and a few others) - ;; we automatically highlight macros. - (add-hook 'emacs-lisp-mode-hook #'seq--activate-font-lock-keywords)) - (defun seq-split (sequence length) "Split SEQUENCE into a list of sub-sequences of at most LENGTH. All the sub-sequences will be of LENGTH, except the last one, @@ -680,5 +695,9 @@ which may be shorter." result)) (nreverse result))) +(defun seq-keep (function sequence) + "Apply FUNCTION to SEQUENCE and return all non-nil results." + (delq nil (seq-map function sequence))) + (provide 'seq) ;;; seq.el ends here |