Feature request: Allow arbitrary message input to expr

[danfuzz]

I'd love to be able to perform computation on arbitrary messages coming into an expr. E.g. maybe I could have an inlet which takes messages of the form get X Y or set X Y V, and I could use functions in expr to extract the symbol, and count / extract arguments.

Or, if nothing else, I could send an incoming message as-is onward to an outlet.

Related issue: #783

[Spacechild1]

again, [expr] is meant for computing mathematical expressions, it's not a general purpose scripting language. just use regular Pd objects.