From ed4781435be1222424c6a364ac12a3fa8813bf9b Mon Sep 17 00:00:00 2001
From: Magnar Sveen <magnars@gmail.com>
Date: Tue, 23 Oct 2012 08:58:24 +0200
Subject: [PATCH] Add -dotimes

---
 README.md   | 10 ++++++++++
 dash.el     | 11 +++++++++++
 examples.el |  4 ++++
 3 files changed, 25 insertions(+)

diff --git a/README.md b/README.md
index 15725a3..8dfb7e4 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ Or you can just dump `dash.el` in your load path somewhere.
 * [-none?](#-none-fn-list) `(fn list)`
 * [-each](#-each-list-fn) `(list fn)`
 * [-each-while](#-each-while-list-pred-fn) `(list pred fn)`
+* [-dotimes](#-dotimes-num-fn) `(num fn)`
 * [-take](#-take-n-list) `(n list)`
 * [-drop](#-drop-n-list) `(n list)`
 * [-take-while](#-take-while-fn-list) `(fn list)`
@@ -238,6 +239,15 @@ Returns nil, used for side-effects only.
 (let (s) (--each-while '(1 2 3 4) (< it 3) (!cons it s)) s) ;; => '(2 1)
 ```
 
+### -dotimes `(num fn)`
+
+Repeatedly calls `fn` (presumably for side-effects) passing in integers from 0 through n-1.
+
+```cl
+(let (s) (-dotimes 3 (lambda (n) (!cons n s))) s) ;; => '(2 1 0)
+(let (s) (--dotimes 5 (!cons it s)) s) ;; => '(4 3 2 1 0)
+```
+
 ### -take `(n list)`
 
 Returns a new list of the first `n` items in `list`, or all items if there are fewer than `n`.
diff --git a/dash.el b/dash.el
index 7a81131..18ebb54 100644
--- a/dash.el
+++ b/dash.el
@@ -64,6 +64,17 @@
 Returns nil, used for side-effects only."
   (--each-while list (funcall pred it) (funcall fn it)))
 
+(defmacro --dotimes (num &rest body)
+  "Repeatedly executes BODY (presumably for side-effects) with `it` bound to integers from 0 through n-1."
+  `(let ((it 0))
+     (while (< it ,num)
+       ,@body
+       (setq it (1+ it)))))
+
+(defun -dotimes (num fn)
+  "Repeatedly calls FN (presumably for side-effects) passing in integers from 0 through n-1."
+  (--dotimes num (funcall fn it)))
+
 (defun -map (fn list)
   "Returns a new list consisting of the result of applying FN to the items in LIST."
   (mapcar fn list))
diff --git a/examples.el b/examples.el
index a0aca3a..e5eb0f5 100644
--- a/examples.el
+++ b/examples.el
@@ -87,6 +87,10 @@
   (let (s) (-each-while '(2 4 5 6) 'even? (lambda (item) (!cons item s))) s) => '(4 2)
   (let (s) (--each-while '(1 2 3 4) (< it 3) (!cons it s)) s) => '(2 1))
 
+(defexamples -dotimes
+  (let (s) (-dotimes 3 (lambda (n) (!cons n s))) s) => '(2 1 0)
+  (let (s) (--dotimes 5 (!cons it s)) s) => '(4 3 2 1 0))
+
 (defexamples -take
   (-take 3 '(1 2 3 4 5)) => '(1 2 3)
   (-take 17 '(1 2 3 4 5)) => '(1 2 3 4 5))