[Haskell] System.Random

Simon Marlow simonmar at microsoft.com
Tue Mar 2 15:16:08 EST 2004

> Now, I don't understand this at all...
> All the development of the Random stuff in all languages has nothing
> of random whatsoever. Perhaps *some* people like to seed the generator
> with the clock time, but most *real* developers *known to me* 
> usually choose
> the seed deterministically, in order to reproduce the sequence, until
> the program is ready to run in the end-user environment.

I suspect that developers requiring a good source of randomness for
security would disagree with you.  Not to say that there aren't lots of
good reasons for having a deterministic pseudo-random generator too (eg.
random test generation), but let's not say that one is more important
than the other.

However, the current System.Random doesn't provide a good interface for
those requiring true randomness.  You have to reseed all the time, and
the implementation is pretty weedy (seeding from /dev/random where
available would be better).

The Random library *could* be split into its pure and IO-ish parts.
It's probably only worth doing if someone were to undertake a
redesign/rewrite of the library.


PS. why on earth did I let myself get dragged into this thread?  I have
no interest in it whatsoever :-S

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