Re: random doesn't feel very random

[Simon Leinen <simon.leinen@gmail.com>]

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On Mon, Aug 27, 2012 at 2:50 AM, Stefan Monnier <monnier@iro.umontreal.ca>wrote:

> > Therefore the PRNG should be seeded once at start-up, from a good
> > source of entropy.
>
> IIRC Emacs fails to seed its PRNG at start (IOW it is seeded with
> a constant), which is why many packages use (random t).
>
> So I think the right thing to do now is to do seed it at startup, then
> make (random t) a no-op.
>
> We could consider adding a way to get the PRNG state and reset it later,
> but since the PRNG state is Emacs-wide and Emacs is more like an OS than
> like an application w.r.t its packages, such an interface would need to
> allow several named PRNGs, so you'd call (random N <id>) to get the next
> "random" number from <id>'s stream.


What about implementing the Common Lisp conventions for treating PRNG
state, i.e. an optional state argument to RANDOM, and a variable
*RANDOM-STATE*?
Instead of (RANDOM T), people could say something like (SETQ *RANDOM-STATE*
(MAKE-RANDOM-STATE T)) if they really want.
-- 
Simon.

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