[PD] here I go again..dynamic abstractions

Frank Barknecht fbar at footils.org
Sat Feb 7 12:32:06 CET 2009

Georg Werner hat gesagt: // Georg Werner wrote:

> can somebody explain why there is a "3rd rule of $-expansion: 'there is 
> no $0 in message-boxes'".
> i stumble every now and then about it and it is IMHO not 
> self-explanatory. it is not hard to implement and wouldn't make problems 
> with existing patches - because $0 is never used in messages. and would 
> make things easier not only for beginners.

Actually this topic is discussed about once or twice a year on pd-list
and pd-dev, so for deeper info check the archive.

Anyway: $0 is a property of the surrounding abstraction or canvas, as
are $1,...  in object arguments. The $1,... in message boxes however
are properties of the messages sent around and reaching a message box.
While the value of dollar variable in message boxes changes all the
time, the value of the canvas-dollars never change.

Messages don't have anything comparable to the canvas' $0. 

A possible alternative use for $0 in messages would be the selector
("list", "symbol", ...) as that is the thing before $1, but
implementing that could be even more confusing to beginners.

 Frank Barknecht            Do You RjDj.me?          _ ______footils.org__

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