[MLton-commit] r5934

[Vesa Karvonen]

Combined generic value hash with the generic type hash.  This should
reduce collisions when using a universal type with a hash function like in
the pickling generic.  Previously, hashing an int 0 and a word 0w0
produced the same hash value.  Now they produce different hash values.

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U   mltonlib/trunk/com/ssh/generic/unstable/detail/value/hash.sml
U   mltonlib/trunk/com/ssh/generic/unstable/public/value/hash.sig

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Modified: mltonlib/trunk/com/ssh/generic/unstable/detail/value/hash.sml
===================================================================
--- mltonlib/trunk/com/ssh/generic/unstable/detail/value/hash.sml	2007-08-23 09:29:55 UTC (rev 5933)
+++ mltonlib/trunk/com/ssh/generic/unstable/detail/value/hash.sml	2007-08-23 09:46:45 UTC (rev 5934)
@@ -28,7 +28,7 @@
    fun hashParam t p =
        if #totWidth p < 0 orelse #maxDepth p < 0
        then raise Domain
-       else fn v => getT t v p
+       else fn v => Word.xorb (Word32.toWord (Arg.typeHash t), getT t v p)
 
    fun hash t = hashParam t {totWidth = 200, maxDepth = 10}
 

Modified: mltonlib/trunk/com/ssh/generic/unstable/public/value/hash.sig
===================================================================
--- mltonlib/trunk/com/ssh/generic/unstable/public/value/hash.sig	2007-08-23 09:29:55 UTC (rev 5933)
+++ mltonlib/trunk/com/ssh/generic/unstable/public/value/hash.sig	2007-08-23 09:46:45 UTC (rev 5934)
@@ -44,4 +44,7 @@
    sharing Rep = Hash
 end
 
-signature WITH_HASH_DOM = TYPE_INFO_CASES
+signature WITH_HASH_DOM = sig
+   include OPEN_CASES TYPE_HASH TYPE_INFO
+   sharing Rep = TypeHash = TypeInfo
+end