A default `Flow` isn't closable because it's cold?

# coroutines

[reactormonk]

A default Flow isn't closable because it's cold?

[Sam]

Correct, a cold flow doesn't do anything except when you collect it, so there would be nothing to "close".

[reactormonk]

Tried making it hot via shareIn, apparently I need something different?

[Sam]

What are you trying to achieve?

[reactormonk]

I have a flow that's got an end (if the hardware it's represented gets disconnected), and I wanna model that

[Sam]

How is the flow created? Is it a regular flow { ... } builder or something more complex?

[Sam]

In a flow builder you can end the flow just like you would end regular function invocation, i.e. by throwing an exception, reaching the end of the function, or returning early

[reactormonk]

It's a channelFlow, but how do I send something into that scope from the outside? Is there something like an MVar in Haskell where I can wait for a single value to be set?

[ephemient]

CompletableDeferred is kinda like a one-time MVar, but I'm still not clear what you're representing

[ephemient]

a flow representing hardware sounds like it should be hot

[itnoles]

https://medium.com/mobile-app-development-publication/kotlins-flow-channelflow-and-callbackflow-made-easy-5e82ce2e27c0

[reactormonk]

So just make a flow hot somewhere along the chain and it's gonna be hot forever? The hot <-> cold is a bit elusive to me, looks like push/pull based streaming?

[ephemient]

yes. cold flow = subscribers pull from producers, hot flow = producers push to subscribers. you can make a cold flow hot by starting a coroutine which pulls from the producer and pushes to its subscribers (that's what .stateIn(scope) and .shareIn(scope) do) but you can't go the other way around