diff --git a/trees/cb/cb.factor b/trees/cb/cb.factor
index 69d306f..df0186d 100644
--- a/trees/cb/cb.factor
+++ b/trees/cb/cb.factor
@@ -14,9 +14,10 @@
 ! critical bit) in a length field (encoded as an integer and a mask) and two
 ! successor pointers. Arbitrary data objects make up its leaves.
 
-USING: accessors arrays assocs combinators.short-circuit fry kernel locals make
-math namespaces parser prettyprint.custom sequences serialize trees
-trees.private vectors ;
+USING: accessors alien arrays assocs byte-arrays combinators.short-circuit fry
+io.binary io.encodings.binary io.encodings.private io.encodings.string
+io.encodings.utf8 kernel layouts locals make math math.private namespaces parser
+prettyprint.custom sequences serialize strings trees trees.private vectors ;
 IN: trees.cb
 
 TUPLE: cb < tree ;
@@ -63,15 +64,35 @@ TUPLE: cb-node { byte# integer } { bits integer } left right ;
         [ 1 255 ] 2dip shorter length 1 -
     ] if* ;
 
+PRIVATE>
+
+GENERIC: key>bytes* ( key -- bytes )
+
+M: object key>bytes*
+    object>bytes ;
+
+M: byte-array key>bytes* ;
+
+M: string key>bytes* utf8 encode ;
+
+M: fixnum key>bytes* cell >le ;
+
+M: bignum key>bytes* dup (log2) 8 /i 1 + >le ;
+
+! Assumes that a double is never larger than a pointer
+M: float key>bytes* double>bits cell >le ;
+
+<PRIVATE
+
+: key>bytes ( key -- bytes )
+    key>bytes* ;
+
 ! Keep the byte sequence of the current key in =key-bytes= and provide a working
 ! environment for it with =with-key=.
 SYMBOL: key-bytes
 SYMBOL: current-key
 SYMBOL: new-side
 
-: key>bytes ( key -- bytes )
-    object>bytes ;
-
 : with-key ( key quot -- )
     [
         { current-key key-bytes new-side } swap