From bd22beb6e4054c659e8c31931c421f60e9719c65 Mon Sep 17 00:00:00 2001 From: Damien Cassou Date: Fri, 21 Oct 2016 07:53:08 +0200 Subject: Add seq-random-elt to seq.el * lisp/emacs-lisp/seq.el (seq-random-elt): Add function to return a random element from it's sequence parameter. * test/lisp/emacs-lisp/seq-tests.el (test-seq-random-elt-take-all test-seq-random-elt-return-nil): Test the new function * doc/lispref/sequences.texi: Document the new function --- lisp/emacs-lisp/seq.el | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'lisp/emacs-lisp/seq.el') diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index 85702f4a64d..5c89d2b3007 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -4,7 +4,7 @@ ;; Author: Nicolas Petton ;; Keywords: sequences -;; Version: 2.18 +;; Version: 2.19 ;; Package: seq ;; Maintainer: emacs-devel@gnu.org @@ -476,6 +476,13 @@ 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. +Return nil if SEQUENCE is nil." + (if (seq-empty-p sequence) + (error "Sequence cannot be empty") + (seq-elt sequence (random (seq-length sequence))))) ;;; Optimized implementations for lists -- cgit v1.2.3