From 0a93877d4be683159f61c050283ef8d37ad21876 Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Mon, 2 Jun 2014 08:40:38 -0700
Subject: [PATCH] sequences: make sum-lengths generic.

---
 core/sequences/sequences.factor | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/core/sequences/sequences.factor b/core/sequences/sequences.factor
index 3c5c8f992b..f27444df3f 100644
--- a/core/sequences/sequences.factor
+++ b/core/sequences/sequences.factor
@@ -819,9 +819,14 @@ PRIVATE>
         [ 0 swap copy-unsafe ] keep reverse!
     ] keep like ;
 
-: sum-lengths ( seq -- n )
+GENERIC: sum-lengths ( seq -- n )
+
+M: object sum-lengths
     0 [ length + ] reduce ;
 
+M: repetition sum-lengths
+    [ len>> ] [ elt>> length ] bi * ;
+
 : concat-as ( seq exemplar -- newseq )
     swap [ { } ] [
         [ sum-lengths over new-resizable ] keep