Re: [boost] C++ classes passed to Python (was Re: Detachable objects in BPL)

From: Karl Bellve (Karl.Bellve_at_[hidden])
Date: 2001-03-26 14:43:11

Phlip: 

Thanks,

But it appears that BPL must first create a python class in the first
line before you can use the second line (m = n.getWorld(1)). In your
example, you have hello::world, which has a function to construct a new
hello::world (getWorld). But, using BPL, how do you load a preexisting
c++ object, already contructed, into python? I assume you just can't do
a "import object\n" and then use its functions? Basically, can you skip
line one in your python code, and go straight to line 2?

Phlip wrote:
> 
> 
> We demonstrate three behaviors here:
> 
>  - Python calls 'new' (the first line would have a 'new' if Python created
> objects like that) and gets a C++ object thru BPL
> 
>  - A C++ method (getWorld) calls 'new' & returns a Pythonized pointer to it
> 
>  - A C++ object does not call new & returns a None, so Python can detect this
> 
> I ended that thread when I figured out how to safely return a None. Boost
> does not (yet) translate a C++ NULL into a None. But I can't remember what
> the thread said - we implemented BPL in our project (replacing SWIG
> [yay!]) and moved on.
> 
> --
>   Phlip                          phlip_cpp_at_[hidden]
> ============== http://phlip.webjump.com ==============
>   --  Whoever dies with the most features wins  --
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-- 
Cheers,
Karl Bellve, Ph.D.                   ICQ # 13956200
Biomedical Imaging Group             TLCA# 7938 		
University of Massachusetts
Email: Karl.Bellve_at_[hidden]
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