[PD] PDDP meeting?

Krzysztof Czaja czaja at chopin.edu.pl
Tue May 9 01:59:22 CEST 2006

Frank Barknecht wrote:
>>So I think that in the message-vs-list case, if there are obscure 
>>problems, they should be transformed into clear problems by teaching them 
>>to every pd user.
> And also to developers: Some of the annoyances with list- vs.
> "meta"-messages are introduced by externals like those inherited from
> Max: [prepend] in all or most of its versions except [list prepend] or
> the zl-family or - in a different way - [OSCroute], because these
> output a meta-message even when they receive a proper list-message and
> thus may introduce unwanted side effects later in the processing chain
> if users aren't aware of this. 

hmm...  I tried to explain this in another thread.  Let me try

1. It is probably fair to say that the Pd rules of message typing
are better than the old rules still preserved in Max.
Nevertheless, Pd is just as unsuitable for list processing as Max.

2. One of the old rules defines lists as multi-atom messages that
start with a number, and declares that messages starting with
a symbol after the 'list' selector are illegal (although Max does
not enforce it fully).  Therefore, [list] cannot be used in
max-compatible patches.

3. Regardless of the rules, [zl]'s and [prepend]'s way of
conversion, i.e. discarding of the 'list' selector of symbolic
list messages is just as bad, good, or irrelevant as the [list]'s
way of conversion, i.e. prepending of the 'list' selector to
non-list messages -- the same bit of information is lost.

4. In nearly all cases when [prepend] is really needed, it is used
for assigning a selector to a message.  Inserting [prepend add]
before a [textfile] is more natural, than inserting
[list prepend add] -> [list trim].  Differentiating a 'list to be
stored' from a 'non-list to be stored' requires a [route list]
anyway, with either [prepend add list] or [list prepend add
list] in one of the branches.


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