>What is wrong with [my_selector(--[list]--[$1(

for instance, [42(--[list]--[$1( will give 42 not float,
similarly [symbol crabs(--[list]--[$1( will give crabs not symbol
Also it seems reasonable to just have 1 object box for querying a selector, which is a main element of the pd
message environment.

>> On the other hand, having $0 represent the selector would be the most consistent solution, because you can not get other patch-local variables
or arguments in message boxes, [...]

>I don't understand what the word "solution" means here. If users
have repeatedly requested msg box $0 to expand to glist's
ce_dollarzero, why would Pd Vanilla give $0 in msg boxes a
different function that is incompatible with object box $0?

here "solution" means a good way to resolve $0 in message boxes..
I don't think what users request is necessarily the end all of reasons to implement a feature in a language..
and again, the reason that $0 would be different in object boxes and message boxes is because everything else already is
different in object and message boxes