From 3014b1828a75103d2036fde318fb82638e4bef09 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Mon, 10 Sep 2012 08:52:42 -0700
Subject: [PATCH] math.transforms.bwt: Simplify two places in bwt.

---
 extra/math/transforms/bwt/bwt.factor | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/extra/math/transforms/bwt/bwt.factor b/extra/math/transforms/bwt/bwt.factor
index 4415c5136c..0b1340a3fd 100644
--- a/extra/math/transforms/bwt/bwt.factor
+++ b/extra/math/transforms/bwt/bwt.factor
@@ -7,9 +7,9 @@ IN: math.transforms.bwt
 ! Inefficient versions of Burrows-Wheeler Transform
 
 : bwt ( seq -- newseq )
-    { 0 } swap append all-rotations natural-sort [ last ] map ;
+    0 suffix all-rotations natural-sort [ last ] map ;
 
 : ibwt ( newseq -- seq )
     [ length [ { } <array> ] keep ] keep
     '[ _ [ prefix ] 2map natural-sort ] times
-    [ { 0 } tail? ] find nip 1 head* ;
+    [ { 0 } tail? ] find nip but-last ;