[PD] Understanding Selectors, Atoms, Lists ...

Frank Barknecht fbar at footils.org
Wed Apr 19 13:11:37 CEST 2006

Sciss hat gesagt: // Sciss wrote:

> this may be related to a thread last week about the nature lists ?
> as a experienced max-user i'm having problems to understand the  
> nature of PD atoms. there seems to be the possibility that an atom is  
> neither a symbol, nor a number nor a list ? like in this patch some  
> inputs leave [route] through the rightmost outlet:

Check http://puredata.info/dev/PdDefinitions 
and http://puredata.info/dev/PdMessages
and http://puredata.info/dev/HansDataTypeDefinitions

Being the author of http://puredata.info/dev/PdMessages I would just
repeat myself here with text from there.

> there seems to be no logic whether one has can use a message "as  
> such" and when one has to prepend the "symbol" selector. also there  
> seems to be no logic whether an object outputs a list "as such" or  
> with a prepended "list" selector ; like [pack] accepts a symbol  
> without "symbol" in the left inlet, but not in the right inlet ; it  
> will output a list prepended by "list" ; if i put this list into  
> [zl], the list-prefix is stripped.

I consider this a bug of [zl]. With newer Pd's you should use [list]
instead for basic operations on lists. [list] *always* outputs a
list-message with list-selector for messages with more than one
element, except [list trim] which trims the selector.

> also, what kind of atom is this [alpha beta gamma( if not a list?

It's something Miller calls a "meta-message". The most common example
is the "set"-meta-message.

 Frank Barknecht                 _ ______footils.org_ __goto10.org__

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