From a454b2e38414bb61fb5dc5b8c91e8bc64f72fcf1 Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Fri, 31 Aug 2012 11:04:12 -0700
Subject: [PATCH] math.extras: adding moving-count.

---
 extra/math/extras/extras-tests.factor | 4 +++-
 extra/math/extras/extras.factor       | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/extra/math/extras/extras-tests.factor b/extra/math/extras/extras-tests.factor
index fe797d916e..1f979ffaa0 100644
--- a/extra/math/extras/extras-tests.factor
+++ b/extra/math/extras/extras-tests.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2012 John Benediktsson
 ! See http://factorcode.org/license.txt for BSD license
 
-USING: math.extras math.ranges tools.test ;
+USING: math math.extras math.ranges tools.test ;
 
 IN: math.extras.test
 
@@ -21,6 +21,8 @@ IN: math.extras.test
 
 { { 2 5 5 4 3 } } [ { 1 2 5 6 1 4 3 } 3 moving-median ] unit-test
 
+{ { 2 1 1 2 1 1 } } [ { 1 1 2 3 5 8 13 } 2 [ odd? ] moving-count ] unit-test
+
 { { } } [ { 0 0 } nonzero ] unit-test
 { { 1 2 3 } } [ { 0 1 0 2 0 3 0 } nonzero ] unit-test
 
diff --git a/extra/math/extras/extras.factor b/extra/math/extras/extras.factor
index 5d48e35181..556549e3b9 100644
--- a/extra/math/extras/extras.factor
+++ b/extra/math/extras/extras.factor
@@ -105,6 +105,9 @@ PRIVATE>
 : moving-sum ( u n -- v )
     <clumps> [ sum ] map ;
 
+: moving-count ( ... u n quot: ( ... elt -- ... ? ) -- ... v )
+    [ <clumps> ] [ [ count ] curry map ] bi* ; inline
+
 : nonzero ( seq -- seq' )
     [ zero? not ] filter ;