io.random: bit faster using set-nth-unsafe.

extra/io/random/random.factor

@@ -2,7 +2,7 @@
 ! See http://factorcode.org/license.txt for BSD license
 
 USING: combinators fry io kernel locals math math.order random
-sequences ;
+sequences sequences.private ;
 
 IN: io.random
 
@@ -19,10 +19,10 @@ PRIVATE>
 :: random-lines ( n -- lines )
     V{ } clone :> accum
     [| line line# |
-        line# n <=> {
-            { +lt+ [ line accum push ] }
-            { +eq+ [ line accum [ push ] [ randomize drop ] bi ] }
-            { +gt+ [ line# random :> r
-                     r n < [ line r accum set-nth ] when ] }
-        } case
+        line# n <= [
+            line accum push
+        ] [
+            line# random :> r
+            r n < [ line r accum set-nth-unsafe ] when
+        ] if
     ] each-numbered-line accum ;