[#99] Add -take-last and -drop-last

README.md

@@ -99,7 +99,9 @@ Functions returning a sublist of the original list.
 * [-non-nil](#-non-nil-list) `(list)`
 * [-slice](#-slice-list-from-optional-to-step) `(list from &optional to step)`
 * [-take](#-take-n-list) `(n list)`
+* [-take-last](#-take-last-n-list) `(n list)`
 * [-drop](#-drop-n-list) `(n list)`
+* [-drop-last](#-drop-last-n-list) `(n list)`
 * [-take-while](#-take-while-pred-list) `(pred list)`
 * [-drop-while](#-drop-while-pred-list) `(pred list)`
 * [-select-by-indices](#-select-by-indices-indices-list) `(indices list)`
@@ -535,20 +537,47 @@ section is returned.  Defaults to 1.
 
 Return a new list of the first `n` items in `list`, or all items if there are fewer than `n`.
 
+See also: [`-take-last`](#-take-last-n-list)
+
 ```el
 (-take 3 '(1 2 3 4 5)) ;; => '(1 2 3)
 (-take 17 '(1 2 3 4 5)) ;; => '(1 2 3 4 5)
 ```
 
+#### -take-last `(n list)`
+
+Return the last `n` items of `list` in order.
+
+See also: [`-take`](#-take-n-list)
+
+```el
+(-take-last 3 '(1 2 3 4 5)) ;; => '(3 4 5)
+(-take-last 17 '(1 2 3 4 5)) ;; => '(1 2 3 4 5)
+(-take-last 1 '(1 2 3 4 5)) ;; => '(5)
+```
+
 #### -drop `(n list)`
 
 Return the tail of `list` without the first `n` items.
 
+See also: [`-drop-last`](#-drop-last-n-list)
+
 ```el
 (-drop 3 '(1 2 3 4 5)) ;; => '(4 5)
 (-drop 17 '(1 2 3 4 5)) ;; => '()
 ```
 
+#### -drop-last `(n list)`
+
+Remove the last `n` items of `list` and return a copy.
+
+See also: [`-drop`](#-drop-n-list)
+
+```el
+(-drop-last 3 '(1 2 3 4 5)) ;; => '(1 2)
+(-drop-last 17 '(1 2 3 4 5)) ;; => '()
+```
+
 #### -take-while `(pred list)`
 
 Return a new list of successive items from `list` while (`pred` item) returns a non-nil value.

dash.el

@@ -673,7 +673,9 @@ section is returned.  Defaults to 1."
     (nreverse new-list)))
 
 (defun -take (n list)
-  "Return a new list of the first N items in LIST, or all items if there are fewer than N."
+  "Return a new list of the first N items in LIST, or all items if there are fewer than N.
+
+See also: `-take-last'"
   (let (result)
     (--dotimes n
       (when list
@@ -681,7 +683,23 @@ section is returned.  Defaults to 1."
         (!cdr list)))
     (nreverse result)))
 
-(defalias '-drop 'nthcdr "Return the tail of LIST without the first N items.")
+(defun -take-last (n list)
+  "Return the last N items of LIST in order.
+
+See also: `-take'"
+  (copy-sequence (last list n)))
+
+(defalias '-drop 'nthcdr
+  "Return the tail of LIST without the first N items.
+
+See also: `-drop-last'")
+
+(defun -drop-last (n list)
+  "Remove the last N items of LIST and return a copy.
+
+See also: `-drop'"
+  ;; No alias because we don't want magic optional argument
+  (butlast list n))
 
 (defmacro --take-while (form list)
   "Anaphoric form of `-take-while'."

dev/examples.el

@@ -168,10 +168,22 @@ new list."
     (-take 3 '(1 2 3 4 5)) => '(1 2 3)
     (-take 17 '(1 2 3 4 5)) => '(1 2 3 4 5))
 
+  (defexamples -take-last
+    (-take-last 3 '(1 2 3 4 5)) => '(3 4 5)
+    (-take-last 17 '(1 2 3 4 5)) => '(1 2 3 4 5)
+    (-take-last 1 '(1 2 3 4 5)) => '(5)
+    (let ((l '(1 2 3 4 5)))
+      (setcar (-take-last 2 l) 1)
+      l) => '(1 2 3 4 5))
+
   (defexamples -drop
     (-drop 3 '(1 2 3 4 5)) => '(4 5)
     (-drop 17 '(1 2 3 4 5)) => '())
 
+  (defexamples -drop-last
+    (-drop-last 3 '(1 2 3 4 5)) => '(1 2)
+    (-drop-last 17 '(1 2 3 4 5)) => '())
+
   (defexamples -take-while
     (-take-while 'even? '(1 2 3 4)) => '()
     (-take-while 'even? '(2 4 5 6)) => '(2 4)