From 454bffc14eea4569416539fad26a15e0b5e4dc56 Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Thu, 12 Sep 2013 12:47:04 -0700
Subject: [PATCH] sequences.extras: adding nth* which is nth from the end.

---
 extra/sequences/extras/extras-tests.factor | 2 ++
 extra/sequences/extras/extras.factor       | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/extra/sequences/extras/extras-tests.factor b/extra/sequences/extras/extras-tests.factor
index 0ee8e5242f..d01f60752e 100644
--- a/extra/sequences/extras/extras-tests.factor
+++ b/extra/sequences/extras/extras-tests.factor
@@ -169,3 +169,5 @@ IN: sequences.extras.tests
 { "foo" " " } [ "foo " [ blank? ] cut-when ] unit-test
 { "" " foo" } [ " foo" [ blank? ] cut-when ] unit-test
 { "foo" " bar" } [ "foo bar" [ blank? ] cut-when ] unit-test
+
+{ { 4 0 3 1 2 } } [ { 0 4 1 3 2 } 5 iota [ nth* ] curry map ] unit-test
diff --git a/extra/sequences/extras/extras.factor b/extra/sequences/extras/extras.factor
index fc6e90744a..03b1fcda5c 100644
--- a/extra/sequences/extras/extras.factor
+++ b/extra/sequences/extras/extras.factor
@@ -486,3 +486,6 @@ PRIVATE>
 : cut-when ( ... seq quot: ( ... elt -- ... ? ) -- ... before after )
     [ find drop ] 2keep drop swap
     [ cut ] [ f over like ] if* ; inline
+
+: nth* ( n seq -- elt )
+    [ length 1 - swap - ] [ nth ] bi ; inline