Is there anything out there for repeatedly reading...

# coroutines

[Casey Brooks]

Is there anything out there for repeatedly reading input from stdin, something like a suspending version of readLine() in a while loop?

[trevjones]

seems like you could create a flow that reads from stdin and yields once per line?

[Zach Klippenstein (he/him) [MOD]]

val File.lines: Flow<String>
    get() = flow<String> {
      useLines { lines ->
        emitAll(lines.asFlow())
      }
    }.flowOn(<http://Dispatchers.IO|Dispatchers.IO>)

[octylFractal]

that might close the source too early, perhaps reader.lineSequence().asFlow().onCompletion { reader.close() }.flowOn(<http://Dispatchers.IO|Dispatchers.IO>)

[Zach Klippenstein (he/him) [MOD]]

Why would it close the source too early? useLines won’t close the source until the block exits, which won’t happen until the collector finishes processing the last line. If anything it will close the source too late, which I think is what your solution fixes.

[trevjones]

asFlow().onCompletion seems suspect to leak on anything but the happy path?

[octylFractal]

I'm not sure what you mean by that Trevor? onCompletion is called upon exception as well iirc

[trevjones]

copy that, rx brain leaking through. not yet a flow user myself

[octylFractal]

zach, yes, I apologize for that. Your version works as well.

[Zach Klippenstein (he/him) [MOD]]

@octylFractal Yours is objectively better, with mine if the last emit call suspends for a long time the file handle is effectively leaked. Could happen if a buffer(RENDEZVOUS) was chained right after the flowOn.