[Haskell-cafe] Re: Pickling a finite map (Binary + zlib) [was: Data.Binary poor read performance]

Christian Maeder Christian.Maeder at dfki.de
Tue Feb 24 13:46:28 EST 2009

>> fromDistinctAscList :: [(k,a)] -> Map k a
>> fromDistinctAscList xs
>>   = build const (length xs) xs
>>   where
>>     -- 1) use continutations so that we use heap space instead of stack space.
>>     -- 2) special case for n==5 to build bushier trees.
>>     build c 0 xs'  = c Tip xs'
>>     build c 5 xs'  = case xs' of
>>                        ((k1,x1):(k2,x2):(k3,x3):(k4,x4):(k5,x5):xx)
>>                             -> c (bin k4 x4 (bin k2 x2 (singleton k1
>> x1) (singleton k3 x3)) (singleton k5 x5)) xx

By the way, did anyone test if (or when) this n==5 case "bushier trees"
gains something?

Thanks Christian

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