[Haskell-cafe] Hangman game

Yitzchak Gale gale at sefer.org
Mon Jan 21 18:41:45 EST 2008


I wrote:
>> Generating an infinite list from a random generator "burns up"
>> the generator, making it unusable for any further calculations.

Jake McArthur wrote:
> That's what the split function is for. ^_^

Yes, that is a nice approach. I have been avoiding it due to
the following comment in the docs for System.Random:

"This is very useful in functional programs... but very little
work has been done on statistically robust implementations
of split ([System.Random#Burton, System.Random#Hellekalek]
are the only examples we know of)."

And my own experience has been that cases where I need split
tend to be in a state monad anyway, where there isn't any
real advantage to split.

That said, looking around briefly, I came up with this paper
by L'Ecuyer et al that does seem to describe a decent
random generator with properties of split worked out:

http://citeseer.ist.psu.edu/493863.html

L'Ecuyer's implementations in C, C++ and Java are here:

http://www.iro.umontreal.ca/~lecuyer/myftp/streams00/

If we had something like that in Haskell, I might use
split more often.

Regards,
Yitz


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