diff options
Diffstat (limited to 'lisp/emacs-lisp/seq.el')
| -rw-r--r-- | lisp/emacs-lisp/seq.el | 54 |
1 files changed, 46 insertions, 8 deletions
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index 904aad0afef..5ddc5a53a32 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -4,7 +4,7 @@ ;; Author: Nicolas Petton <nicolas@petton.fr> ;; Keywords: sequences -;; Version: 2.3 +;; Version: 2.19 ;; Package: seq ;; Maintainer: emacs-devel@gnu.org @@ -87,7 +87,7 @@ given, and the match does not fail." ARGS can also include the `&rest' marker followed by a variable name to be bound to the rest of SEQUENCE." - (declare (indent 2) (debug t)) + (declare (indent 2) (debug (sexp form body))) `(pcase-let ((,(seq--make-pcase-patterns args) ,sequence)) ,@body)) @@ -117,6 +117,16 @@ Return SEQUENCE." (defalias 'seq-each #'seq-do) +(defun seq-do-indexed (function sequence) + "Apply FUNCTION to each element of SEQUENCE and return nil. +Unlike `seq-map', FUNCTION takes two arguments: the element of +the sequence, and its index within the sequence." + (let ((index 0)) + (seq-do (lambda (elt) + (funcall function elt index) + (setq index (1+ index))) + sequence))) + (cl-defgeneric seqp (sequence) "Return non-nil if SEQUENCE is a sequence, nil otherwise." (sequencep sequence)) @@ -144,6 +154,18 @@ if positive or too small if negative)." sequence) (nreverse result))) +(defun seq-map-indexed (function sequence) + "Return the result of applying FUNCTION to each element of SEQUENCE. +Unlike `seq-map', FUNCTION takes two arguments: the element of +the sequence, and its index within the sequence." + (let ((index 0)) + (seq-map (lambda (elt) + (prog1 + (funcall function elt index) + (setq index (1+ index)))) + sequence))) + + ;; faster implementation for sequences (sequencep) (cl-defmethod seq-map (function (sequence sequence)) (mapcar function sequence)) @@ -206,6 +228,16 @@ The result is a sequence of the same type as SEQUENCE." (cl-defmethod seq-sort (pred (list list)) (sort (seq-copy list) pred)) +(defun seq-sort-by (function pred sequence) + "Sort SEQUENCE using PRED as a comparison function. +Elements of SEQUENCE are transformed by FUNCTION before being +sorted. FUNCTION must be a function of one argument." + (seq-sort (lambda (a b) + (funcall pred + (funcall function a) + (funcall function b))) + sequence)) + (cl-defgeneric seq-reverse (sequence) "Return a sequence with elements of SEQUENCE in reverse order." (let ((result '())) @@ -284,7 +316,8 @@ If SEQUENCE is empty, return INITIAL-VALUE and FUNCTION is not called." t)) (cl-defgeneric seq-some (pred sequence) - "Return the first value for which if (PRED element) is non-nil for in SEQUENCE." + "Return non-nil if PRED is satisfied for at least one element of SEQUENCE. +If so, return the first non-nil value returned by PRED." (catch 'seq--break (seq-doseq (elt sequence) (let ((result (funcall pred elt))) @@ -317,7 +350,8 @@ found or not." "Return the first element in SEQUENCE that is equal to ELT. Equality is defined by TESTFN if non-nil or by `equal' if nil." (seq-some (lambda (e) - (funcall (or testfn #'equal) elt e)) + (when (funcall (or testfn #'equal) elt e) + e)) sequence)) (cl-defgeneric seq-position (sequence elt &optional testfn) @@ -443,16 +477,20 @@ SEQUENCE must be a sequence of numbers or markers." "Return element of SEQUENCE at the index N. If no element is found, return nil." (ignore-errors (seq-elt sequence n))) + +(cl-defgeneric seq-random-elt (sequence) + "Return a random element from SEQUENCE. +Signal an error if SEQUENCE is empty." + (if (seq-empty-p sequence) + (error "Sequence cannot be empty") + (seq-elt sequence (random (seq-length sequence))))) ;;; Optimized implementations for lists (cl-defmethod seq-drop ((list list) n) "Optimized implementation of `seq-drop' for lists." - (while (and list (> n 0)) - (setq list (cdr list) - n (1- n))) - list) + (nthcdr n list)) (cl-defmethod seq-take ((list list) n) "Optimized implementation of `seq-take' for lists." |