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Date: Mon, 30 Jan 2017 16:29:43 +0000
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Subject: Re: Reseeding rand()/mt_rand()
From: ajf@ajf.me (Andrea Faulds)

Hi Christoph,

Christoph M. Becker wrote:

> Just a quick idea:
>
> <?php
>
> class PNRG {
>     public function __construct($seed = null) {…}
>     public function get() {…}
> }
>

I've long favoured an API along these lines. One size does not fit all, 
you need two APIs for (non-crytographic) random numbers:
- automatically-seeded, non-reproducible numbers (a global function like 
rand())
- manually-seeded, reproducible number sequences (objects)

Currently we mix these two, and it's a mess. The easy solution would be 
a random number-generating object like you propose, to cover the second 
use-case. We could also introduce a non-manually-seedable global PRNG 
also, if desired. Perhaps as a static method of that class.

One thought: it'd be nice if you had two different methods, one that 
mutates in places, and one that doesn't, i.e.:

$prng1 = new PRNG(SEED);
[$randomNumber, $prng2] = $prng2->getWithNewPRNG();

v.s.:

$prng = new PRNG(SEED);
$randomNumber = $prng->get();
$randomNumber2 = $prng->get();

Thanks!

-- 
Andrea Faulds
https://ajf.me/