$0 is not a symbol. It is internally rendered to a number.
OK, got it.
Is this documented anywhere?
You can also give preset values to many objects, i.e. [pack 10 $0].
Ah, that's very nice. It hasn't entered my vocabulary yet. Maybe it will sink in now.
If you want that preset value to be a constant you should always precede the left inlet with something which will keep out accidental lists...
In fact, I have two of them:
[f], and a
f outlet of a trigger.
Also, when naming things with $0, it seems best to always do name-$0 instead of $0-name as most every example does,
Understood, but... again, is this documented anywhere? "13.locality.pd" demonstrates $0 as a prefix -- if this is out of date, shouldn't somebody put in a pull request to update the help file?
Anyway, with that, I was able to wrap up this moving-average abstraction: