[PD] Finding "$0" and dealing with it in messages

[Roman Haefeli]

Am 13.11.09 01:31 schrieb "Phil Stone" unter <pkstone at ucdavis.edu>:

> Mathieu Bouchard wrote:
>> On Fri, 13 Nov 2009, Frank Barknecht wrote:
>>> Alexandre Porres hat gesagt: // Alexandre Porres wrote:
>>>> But I totally disagree, I have been teaching a lot basic Pd around, and
>>>> people always get confused and think they can just throw "$0" in
>>>> messages.
>>> That may be because your students assume, that $1 in a message box is
>>> the same
>>> as $1 in an object box when in fact it's something different.
>> 
>> That may be because you assume that objectboxes' $0 must have
>> something to do with $1,$2,$3,... when in fact it's something different.
>> 
>>   $3 stands for ce_argv[2]
>>   $2 stands for ce_argv[1]
>>   $1 stands for ce_argv[0]
>>   $0 stands for ce_dollarzero
>> 
>> it's a special case no matter what.
> 
> Right.  Which neatly brings the question back around to "why can't $0 be
> used in message boxes?"  I've said this before (to no avail): it is well
> understood that $0 has no meaning in *messages* -- however, this is not
> a good reason why $0 can't be used in *message boxes.*
> 
> Since "1024-foo" (where "1024" represents the canvas-identifier), *does*
> have meaning in messages, why must we jump through (admittedly minor,
> but still quite annoying) hoops just to get that canvas-identifier into
> a message?
> 
> It probably belongs in the "some things will never change in Pd"
> category; therefore we must resign ourselves to this discussion
> re-appearing on a regular basis.

$0 in messages is only special in the sense, that it has no meaning at all.
it wouldn't make it less special to use it as a container for canvas
identifier in message boxes. $-variables in objects have a different meaning
from $-variables in message boxes, no matter what. I understand, that it
would make patching often a lot easier, but conceptually it would be
exceptional to make $0 in message-boxes be replaced by the
canvas-identifier, while all other $n-variables in message-boxes get
replaced by the n-th element of the incoming list. I wouldn't want to have
to pay attention to n in $n in order to determine its behaviour. And i also
don't support a change that would introduce an inconsistency like that. Why
don't people fight with the same effort to make $1 in message boxes be
replaced by the first argument of the patch?

Personally, i find it 'unecological' to just not use $0 at all in message
boxes.  I am haven't checked, but i think this idea must have been brought
up already:

Let's make $0 in message boxes be replaced by the selector of the incoming
messages. Currently, it is quite cumbersome to type check a pd message and
it requires a lot of patching. Using $0 to get the '0th' element of the
incoming message would be consistent with the way $-variables are currently
used in message boxes and it would be tremendously useful. Just to
illustrate the proposed use of $0:

the incoming message:       the respective $0
'hallo velo'                'hallo'
'list mein fahrrad'         'list'
'symbol bike'               'symbol'
'12 twentyfour'             'list'
'12'                        'float'
'bang'                      'bang'
'bla'                       'bla'

If this could be implemented, any future discussion about why $0 in message
boxes is not replaced by the canvas identifier would be lapsed.

roman




	
		
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