[MLton-commit] r5534

[Vesa Karvonen]

Simplified and optimized nubByEq.  The optimization is that equality tests
are only made against the accumulated list of unique elements.

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U   mltonlib/trunk/com/ssh/extended-basis/unstable/detail/sequence/list.sml

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Modified: mltonlib/trunk/com/ssh/extended-basis/unstable/detail/sequence/list.sml
===================================================================
--- mltonlib/trunk/com/ssh/extended-basis/unstable/detail/sequence/list.sml	2007-04-19 17:44:27 UTC (rev 5533)
+++ mltonlib/trunk/com/ssh/extended-basis/unstable/detail/sequence/list.sml	2007-04-21 16:33:32 UTC (rev 5534)
@@ -116,18 +116,7 @@
    in
      fun divideByEq eq xs = divideByEqTail eq xs []
    end
-
-   local
-     fun nubByEqTail eq xs accum = 
-         case xs
-           of [] => accum
-            | x::xs' =>
-                if exists (Fn.curry eq x) xs' then
-                  nubByEqTail eq xs' accum
-                else 
-                  nubByEqTail eq xs' (x::accum)   
-   in
-     fun nubByEq eq xs = nubByEqTail eq (rev xs) []
-   end
-
+   fun nubByEq eq =
+       rev o foldl (fn (x, ys) =>
+                       if exists (Fn.curry eq x) ys then ys else x::ys) []
 end