[PD-dev] string type for pd

[Martin Peach]

Bryan Jurish wrote:
> moin Martin,
>
> On 2007-02-04 00:40:03, Martin Peach <martin.peach at sympatico.ca> appears
> to have written:
>   
>> Bryan Jurish wrote:
>>     
>>> at any rate, a thousand thanks for your work, and I'm looking forward to
>>> playing with real strings in pd!
>>>
>>>   
>>>       
>> Good to know I've done something useful for once!
>> I guess my question now is whether it's best to have a single [str]
>> object with lots of selectors for different functions a la [list] as I
>> did in str.c, or a bunch of objects like [str_join] [str_split] all in a
>> str library, or individual objects in "flatspace".
>>     
>
> I myself am partial to multiple objects, for semantic and
> coding-aesthetic reasons, but I can see that the parallel to [list]
> could be a motivation for the single-object approach.  As to the
> question of library vs. a flat collection of single-object externals, I
> suppose the question is just how much of a common codebase would the
> various objects need?  you could also even make multiple build targets
> (ext13 style) for the library and the flat collection, leaving the
> choice up to the user...
>
>   
The only common codebase is what's exposed in m_pd.h and implemented in 
the patch, which is the minimum that enables pd to pass strings through 
inlets and outlets. How you allocate and destroy string space and how 
big the strings are is up to you, so you need to take that into account 
when processing string messages. IOW the string atom itself only 
contains a pointer to the string data, pd doesn't know anything about 
the data itself. In the [str] object I found it easier to use a common 
set of functions for the various selectors than to repeat them once for 
each type, but I think it would be too constraining to force everyone to 
use those (basically just the allocation and freeing of the string data).
I also experimented with dynamically resizing the strings using 
resizebytes, but found that it would inevitably crash pd, so I settled 
on allocating a large block for each string and using a private variable 
to hold the current length of the string.
Martin