[PD] definitions of data types

Hans-Christoph Steiner hans at eds.org
Mon Feb 6 22:11:43 CET 2006


On Feb 6, 2006, at 3:25 PM, Martin Peach wrote:

> Hans-Christoph Steiner wrote:
>
>>
>> On Feb 6, 2006, at 2:05 PM, Martin Peach wrote:
>>
>>> Hans-Christoph Steiner wrote:
>>>
>>>> Here are some attempts at definitions:
>>>>
>>>> list:  a series of 2 or more elements whose first element is either  
>>>>  the  selector "list", or a float, which causes the "list" selector  
>>>> to  be  implied.  A 0-element list is a bang, a 1-element list is  
>>>> either  a  float or a symbol, are there any exceptions where a 0-  
>>>> or  1-element  lists actually exists?  I suppose only in a message  
>>>> box.
>>>>
>>> ...
>>>
>>>> selector series: a series of 2 or more elements whose first element  
>>>>  is  neither the selector "list" nor a numeric element.  But it  
>>>> needs  a  better term.
>>>>
>>> I would call that an implicit list, and to be consistent with the  
>>> way  float works, it should have list prepended to it by pd and  
>>> otherwise  become indistinguishable from list.
>>
>>
>> But its not a list because objects that deal with lists say so.   
>> "list"  is a keyword in Pd, so we need to define these things using  
>> other  words.  Try this to see what I mean:
>>
>> [one 2 three four(
>> |
>> [route list]
>>
>
> Yes but to me
> [1 two three four(
> and
> [one two three four(
> are both lists and pd shouldn't treat them differently as it now does.

This is one of the sources of confusion, but its a difficult question  
of how _should_ Pd do it.  So for now, I am trying to document all the  
details of Pd actually does it from within Pd.

> From m_pd.h these are all the atom types:
>
> typedef enum
> {
>    A_NULL,
>    A_FLOAT,
>    A_SYMBOL,
>    A_POINTER,
>    A_SEMI,
>    A_COMMA,
>    A_DEFFLOAT,
>    A_DEFSYM,
>    A_DOLLAR,
>    A_DOLLSYM,
>    A_GIMME,
>    A_CANT
> }  t_atomtype;
>
> There is no list atom-type. A list is just a list of atoms. The  
> existence of more than one atom in a message implies that it is a  
> list.
>
> Martin

I put the atom types any other things into this wiki page.  Please add  
anything that's missing, especially documentation of odd cases of  
message/data handling.  At the bottom are links to Frank's and my stabs  
at definitions.

http://puredata.org/dev/PdDefinitions

.hc



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