branch: externals/compat
commit 694647ff667706812d8b3e3c0cd795541673f765
Author: Daniel Mendler <m...@daniel-mendler.de>
Commit: Daniel Mendler <m...@daniel-mendler.de>
compat-30: Add drop
---
NEWS.org | 1 +
compat-30.el | 2 ++
compat-tests.el | 6 ++++++
compat.texi | 7 +++++++
4 files changed, 16 insertions(+)
diff --git a/NEWS.org b/NEWS.org
index c7ca3bef14..15e5e7b576 100644
--- a/NEWS.org
+++ b/NEWS.org
@@ -7,6 +7,7 @@
- compat-30: Add extended =copy-tree= with support for copying records with
non-nil optional second argument.
- compat-30: New macro =static-if=.
+- compat-30: New alias =drop=.
- compat-30: New function =merge-ordered-lists=.
- compat-30: New variables =completion-lazy-hilit= and
=completion-lazy-hilit-fn=
and new function =completion-lazy-hilit=.
diff --git a/compat-30.el b/compat-30.el
index cd9ad76ea1..4d9c5b1e74 100644
--- a/compat-30.el
+++ b/compat-30.el
@@ -136,6 +136,8 @@ details."
;;;; Defined in subr.el
+(compat-defalias drop nthcdr) ;; <compat-tests:drop>
+
(compat-defun merge-ordered-lists (lists &optional error-function) ;;
<compat-tests:merge-ordered-lists>
"Merge LISTS in a consistent order.
LISTS is a list of lists of elements.
diff --git a/compat-tests.el b/compat-tests.el
index d88542526b..6270f8c227 100644
--- a/compat-tests.el
+++ b/compat-tests.el
@@ -957,6 +957,12 @@
(should-equal '(1 2) (take 5 '(1 2)))
(should-equal '(1 2 3) (take 3 '(1 2 3 4))))
+(ert-deftest compat-drop ()
+ (static-if (< emacs-major-version 30) ;; TODO reenable if available on CI
+ (progn
+ (should-not (drop 5 nil))
+ (should-equal '(3 4 5) (drop 2 '(1 2 3 4 5))))))
+
(ert-deftest compat-format-message ()
(should-equal (format-message "a=%s b=%s" 1 2) "a=1 b=2"))
diff --git a/compat.texi b/compat.texi
index 68ae8766b9..825f348e8e 100644
--- a/compat.texi
+++ b/compat.texi
@@ -3350,6 +3350,13 @@ older than 30.1. Note that due to upstream changes, it
might happen
that there will be the need for changes, so use these functions with
care.
+@c based on lispref/lists.texi
+@defun drop n list
+This function is an alias for @code{nthcdr}. It returns the @var{n}th
+@sc{cdr} of @var{list}. In other words, it skips past the first
+@var{n} links of @var{list} and returns what follows.
+@end defun
+
@defun get-truename-buffer filename
Return the buffer with @code{file-truename} equal to @var{filename} (a string).
If there is no such live buffer, return nil.
