From 314dc05ab0075e14227352eed7522a3853043b74 Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Tue, 19 Jun 2012 14:23:00 -0700
Subject: [PATCH] math.extras: adding nonzero.

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

diff --git a/extra/math/extras/extras-tests.factor b/extra/math/extras/extras-tests.factor
index 5514932025..aa33351d59 100644
--- a/extra/math/extras/extras-tests.factor
+++ b/extra/math/extras/extras-tests.factor
@@ -20,3 +20,6 @@ IN: math.extras.test
 [ 10 [1,b] 2 exponential-moving-average ] unit-test
 
 { { 2 5 5 4 3 } } [ { 1 2 5 6 1 4 3 } 3 moving-median ] 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 9bc4d4409c..812de63c47 100644
--- a/extra/math/extras/extras.factor
+++ b/extra/math/extras/extras.factor
@@ -94,3 +94,6 @@ PRIVATE>
 
 : moving-median ( u n -- v )
     <clumps> [ median ] map ;
+
+: nonzero ( seq -- seq' )
+    [ zero? not ] filter ;