From 51530700f406f2effe8ff1f6cde953a10d7a0665 Mon Sep 17 00:00:00 2001
From: Aaron Schaefer <aaron@elasticdog.com>
Date: Wed, 7 Jan 2009 18:47:32 -0500
Subject: [PATCH] Add number-length word and clean cartesian-product

---
 extra/project-euler/common/common.factor | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/extra/project-euler/common/common.factor b/extra/project-euler/common/common.factor
index 1a57a91e5e..49eb730632 100644
--- a/extra/project-euler/common/common.factor
+++ b/extra/project-euler/common/common.factor
@@ -56,7 +56,7 @@ PRIVATE>
     >lower [ CHAR: a - 1+ ] sigma ;
 
 : cartesian-product ( seq1 seq2 -- seq1xseq2 )
-    swap [ swap [ 2array ] with map ] with map concat ;
+    [ [ 2array ] with map ] curry map concat ;
 
 : log10 ( m -- n )
     log 10 log / ;
@@ -74,6 +74,9 @@ PRIVATE>
 : number>digits ( n -- seq )
     [ dup 0 = not ] [ 10 /mod ] [ ] produce reverse nip ;
 
+: number-length ( n -- m )
+    log10 floor 1+ >integer ;
+
 : nth-triangle ( n -- n )
     dup 1+ * 2 / ;