Generate UUID - Polysemy

Which builtin effect(s) are recommended for use when generating UUIDs?

@Sridhar Ratnakumar do you have concrete initial seed? If not, you'll probably need source of randomness = IO

Would it be a bad idea to have a single seed for the entire lifecycle of a backend process when it comes to generating UUIDs (triggered by different app users)?

Probably not.

So I could just use Input to pass around this seed from main

Wait, that won't work.

But if it restarts for some reason, it will start assigning the same UUIDs, won't it?

I need to update it as well.

The initial seed will be generated in IO and random.

Guess I need to track the seed in Polysemy.State

I just wonder whether it makes sense to pass seed around in pure State or whether you could just create mutable var once you're already using IO

The later is probably better. So Polysemy.Random is out of core?

Wait wait, I misread

It's in polysemy-zoo - if you don't mind dependencies, you can use it

Last time I tried it I had trouble with making deps happy in nix. It is called a zoo after all.

I suppose I could just create a UUID effect.

/me looks at https://github.com/polysemy-research/polysemy-zoo/pull/60

Well, there is always unsafePerformIO lol

Running nextRandom into IO seems reasonable - you probably have it in your stack somewhere anyway, so I don't think there's any reason to lie about purity :slight_smile:

Oh yea, I can do IO. But you have to create a whole new GADT with one constructor nextUUID just for this right?

You need new effect if you don't want to use Embed IO directly

if it's going to be an effect with only one constructor that gives a value you might as well use Input, or am I missing something?