From: Stefan Kangas Date: Fri, 17 Sep 2021 08:35:13 +0000 (+0200) Subject: Add new sequence function 'seq-union' X-Git-Tag: emacs-28.0.90~910 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=0cf0a2b98671671bb7639a17639ef2552b772cbe;p=emacs.git Add new sequence function 'seq-union' * lisp/emacs-lisp/seq.el (seq-union): New function. * doc/lispref/sequences.texi (Sequence Functions): * lisp/emacs-lisp/shortdoc.el (sequence): Document above new function. * test/lisp/emacs-lisp/seq-tests.el (test-seq-union): New test. --- diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi index 20816ce8ca2..53d37199bf7 100644 --- a/doc/lispref/sequences.texi +++ b/doc/lispref/sequences.texi @@ -953,6 +953,22 @@ contain less elements than @var{n}. @var{n} must be an integer. If @end example @end defun +@defun seq-union sequence1 sequence2 &optional function +@cindex sequences, union of +@cindex union of sequences + This function returns a list of the elements that appear either in +@var{sequence1} or @var{sequence2}. If the optional argument +@var{function} is non-@code{nil}, it is a function of two arguments to +use to compare elements instead of the default @code{equal}. + +@example +@group +(seq-union [1 2 3] [3 5]) +@result{} (1 2 3 5) +@end group +@end example +@end defun + @defun seq-intersection sequence1 sequence2 &optional function @cindex sequences, intersection of @cindex intersection of sequences diff --git a/etc/NEWS b/etc/NEWS index eee6d2592bd..b1ad4dd1263 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -3855,6 +3855,11 @@ This function is like 'require', but searches 'custom-theme-load-path' instead of 'load-path'. It can be used by Custom themes to load supporting Lisp files when 'require' is unsuitable. ++++ +** New function 'seq-union'. +This function takes two sequences and returns a list of all elements +that appear in either of them. + +++ ** New function 'syntax-class-to-char'. This does almost the opposite of 'string-to-syntax' -- it returns the diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el index f0dc283f57d..b7dcde87f41 100644 --- a/lisp/emacs-lisp/seq.el +++ b/lisp/emacs-lisp/seq.el @@ -467,6 +467,17 @@ negative integer or 0, nil is returned." (setq sequence (seq-drop sequence n))) (nreverse result)))) +(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." + (let ((accum (lambda (acc elt) + (if (seq-contains-p acc elt testfn) + acc + (cons elt acc))))) + (seq-reverse + (seq-reduce accum sequence2 + (seq-reduce accum sequence1 '()))))) + ;;;###autoload (cl-defgeneric seq-intersection (sequence1 sequence2 &optional testfn) "Return a list of the elements that appear in both SEQUENCE1 and SEQUENCE2. diff --git a/lisp/emacs-lisp/shortdoc.el b/lisp/emacs-lisp/shortdoc.el index adee6be379d..3e0d5aef022 100644 --- a/lisp/emacs-lisp/shortdoc.el +++ b/lisp/emacs-lisp/shortdoc.el @@ -809,6 +809,8 @@ There can be any number of :example/:result elements." :eval (seq-remove #'numberp '(1 2 c d 5))) (seq-group-by :eval (seq-group-by #'cl-plusp '(-1 2 3 -4 -5 6))) + (seq-union + :eval (seq-union '(1 2 3) '(3 5))) (seq-difference :eval (seq-difference '(1 2 3) '(2 3 4))) (seq-intersection diff --git a/test/lisp/emacs-lisp/seq-tests.el b/test/lisp/emacs-lisp/seq-tests.el index 44e855e2cfa..bf79dd922bf 100644 --- a/test/lisp/emacs-lisp/seq-tests.el +++ b/test/lisp/emacs-lisp/seq-tests.el @@ -336,6 +336,38 @@ Evaluate BODY for each created sequence. (should (same-contents-p list vector)) (should (vectorp vector)))) +(ert-deftest test-seq-union () + (let ((v1 '(1 2 3)) + (v2 '(3 5))) + (should (same-contents-p (seq-union v1 v2) + '(1 2 3 5)))) + + (let ((v1 '(1 2 3 4 5 6)) + (v2 '(4 5 6 7 8 9))) + (should (same-contents-p (seq-union v1 v2) + '(1 2 3 4 5 6 7 8 9)))) + + (let ((v1 '(1 2 3 4 5 6)) + (v2 '(4 5 6 7 8 9))) + (should (same-contents-p (seq-union v1 v2) + '(1 2 3 4 5 6 7 8 9)))) + + (let ((v1 [1 2 3 4 5]) + (v2 [4 5 6 "a"])) + (should (same-contents-p (seq-union v1 v2) + '(1 2 3 4 5 6 "a")))) + + (let ((v1 '("a" "b" "c")) + (v2 '("f" "c" "e" "a"))) + (should (same-contents-p (seq-union v1 v2) + '("a" "b" "c" "f" "e")))) + + (let ((v1 '("a")) + (v2 '("a")) + (testfn #'eq)) + (should (same-contents-p (seq-union v1 v2 testfn) + '("a" "a"))))) + (ert-deftest test-seq-intersection () (let ((v1 [2 3 4 5]) (v2 [1 3 5 6 7]))