[PD-dev] Re: [PD] VASP future

[Krzysztof Czaja]

Thomas Grill wrote:
...
> I have to investigate whether it's feasible with two-level references to 
> also reuse PD symbols for PyObject pointers.

yes, one way to do that might be picking unique global symbols,
different for every wrappee.  These symbols could be bound to
t_pd objects of a class that defines a dummy 'anything' method.
In order to deal with accidental alien bindings, the objects
would have to be accessed by a pd_findbyclass() call.

The plustot way is different, since it does not pollute the
global symbol table.  The current version is only experimental.
It seems possible to make it robust, although no obvious way to
avoid leaking small portions of memory with every new symbol.
This is not a very big deal, since for each [+tot] object the
number of wrapped tcl objects is small and constant.

> PS. I wonder how an appropriate t_atom type would look like - it seems 
> like additionally to a void *pointer there should also be some namespace 
> ID (the generator instance of the pointer) - that means a new structure 
> like t_symbol and a respective pointer as a union member into t_atom.

some sort of identification will be needed for sure, at least if
this is to be a single blob-like type (still a very vague idea
for me...)

> PPS. In this respect quite unrelated - i can't really express how i like 
> Mathieu's idea of local symbol tables - i wish someone takes the time to 
> implement a draft into devel_0_38 - to my mind this would be a big leap 
> forwards

I have missed that one, I am afraid.  Is it about keeping
$0-symbols in local hash tables, or about introducing a new
special syntax?  How a local symbol would be prevented from
spilling out of local context?

Krzysztof