Understanding "unit" returned from some functions

[vrtisworks]

I am in the process of upgrading from 1.x to 2.0

This worked in 1.x
localOut = ref output.dummy(blank())
...
some code that eventually sets localOut to a real value
...
source.shutdown(!localOut)

I have tried various combinations of parentheses and :source in different places. I get various syntax messages. So, apparently I haven't got a good enough understanding of how this works in 2.0

Can somebody point me in the righth direction or help figure out how to get this working?
Thanks a bunch

[rrolla]

I think this is related to
https://www.liquidsoap.info/doc-dev/migrating.html#returned-types-from-output-operators

[vrtisworks]

I read that, and it sounds sort of reasonable. except the following "works".

localAudio=output.alsa(....,id="localID")
print(localAudio.id())

will print out "localID"
So I think I am missing some basic concept.

[toots]

I discovered this id method thing recently,. It is kind of an oversight but this is fine.

With 2.x we decided to switch output returned type to unit. This is because outputs should really be leaf nodes in the streaming graph and not be re-used for other purposes.

The attached methods were kept without realizing it, tho this is perfectly fine. In liquisoap 2.x, any type can have attached methods, for instance an int with a square method returning its root square.

Lastly, to shutdown an output, I believe you should be able to simply shutdown the source attached to it, for instance:

s = single("/path/to/bla.ogg")
output.xxx(..., s)

# Later:
source.shutdown(s)

This should also shutdown the output.