From 0e5acda7a5a6034d3eb0bd42ca17206dff51964b Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <contovob@tcd.ie>
Date: Mon, 18 Jan 2021 09:03:57 +0000
Subject: [PATCH] Simplify -non-nil

* dash.el (-non-nil): Use --filter for speed.
* dev/examples.el (-non-nil): Extend tests.

* README.md:
* dash.texi: Regenerate docs.
---
 README.md       |  6 ++++--
 dash.el         |  4 ++--
 dash.texi       | 12 ++++++++++--
 dev/examples.el |  7 ++++++-
 4 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 135bc88..036cbcd 100644
--- a/README.md
+++ b/README.md
@@ -586,10 +586,12 @@ The comparison is done with `equal`.
 
 #### -non-nil `(list)`
 
-Return all non-nil elements of `list`.
+Return a copy of `list` with all nil items removed.
 
 ```el
-(-non-nil '(1 nil 2 nil nil 3 4 nil 5 nil)) ;; => '(1 2 3 4 5)
+(-non-nil '(nil 1 nil 2 nil nil 3 4 nil 5 nil)) ;; => '(1 2 3 4 5)
+(-non-nil '((nil))) ;; => '((nil))
+(-non-nil '()) ;; => '()
 ```
 
 #### -slice `(list from &optional to step)`
diff --git a/dash.el b/dash.el
index 449b53a..a800a1d 100644
--- a/dash.el
+++ b/dash.el
@@ -530,9 +530,9 @@ If you want to select the original items satisfying a predicate use `-filter'."
   (--keep (funcall fn it) list))
 
 (defun -non-nil (list)
-  "Return all non-nil elements of LIST."
+  "Return a copy of LIST with all nil items removed."
   (declare (pure t) (side-effect-free t))
-  (-remove 'null list))
+  (--filter it list))
 
 (defmacro --map-indexed (form list)
   "Anaphoric form of `-map-indexed'."
diff --git a/dash.texi b/dash.texi
index e55522b..1d2ac44 100644
--- a/dash.texi
+++ b/dash.texi
@@ -603,13 +603,21 @@ The comparison is done with @code{equal}.
 
 @anchor{-non-nil}
 @defun -non-nil (list)
-Return all non-nil elements of @var{list}.
+Return a copy of @var{list} with all nil items removed.
 
 @example
 @group
-(-non-nil '(1 nil 2 nil nil 3 4 nil 5 nil))
+(-non-nil '(nil 1 nil 2 nil nil 3 4 nil 5 nil))
     @result{} '(1 2 3 4 5)
 @end group
+@group
+(-non-nil '((nil)))
+    @result{} '((nil))
+@end group
+@group
+(-non-nil '())
+    @result{} '()
+@end group
 @end example
 @end defun
 
diff --git a/dev/examples.el b/dev/examples.el
index ebe616b..eb813f3 100644
--- a/dev/examples.el
+++ b/dev/examples.el
@@ -209,7 +209,12 @@ new list."
     (let ((l (list 1 2))) (setcar (-remove-item 2 l) 0) l) => '(1 2))
 
   (defexamples -non-nil
-    (-non-nil '(1 nil 2 nil nil 3 4 nil 5 nil)) => '(1 2 3 4 5))
+    (-non-nil '(nil 1 nil 2 nil nil 3 4 nil 5 nil)) => '(1 2 3 4 5)
+    (-non-nil '((()))) => '((()))
+    (-non-nil '()) => '()
+    (let ((l (list 1 2))) (setcar (-non-nil l) 0) l) => '(1 2)
+    (let ((l (list nil 1))) (setcar (-non-nil l) 0) l) => '(nil 1)
+    (let ((l (list 1 nil))) (setcar (-non-nil l) 0) l) => '(1 nil))
 
   (defexamples -slice
     (-slice '(1 2 3 4 5) 1) => '(2 3 4 5)