[PySide] PySide is Dead?

Joel B. Mohler jmohler at gamry.com
Mon Dec 10 18:55:35 CET 2012

On 12/10/2012 12:42 PM, John Ehresman wrote:
> On 12/10/12 12:32 PM, Hugo Parente Lima wrote:
>>> My thought on the code generator was to have the C++ parser write
>>> the parse tree out to some xml file that could then be read by a
>>> code generator written in python.  Then the C++ parser could
>>> possibly be replaced with something else and the generator could
>>> be more quickly improved since it's now implemented in python.
>>> Changing it would still require C++ knowledge, though, because
>>> it's emitting C++ code.
>> There's GCCXML[1], so the python program just read the output of
>> GCC XML plus some other file with meta information equivalent to
>> the current typesystem but less verbose and outputs the binding
>> code, seems easy, but it's a looooonnng task.
> As a first small step, I would modify shiboken to output the parse
> tree from its internal C++ parser.  I would do this mainly to minimize
> the changes to the generator and the goal here is to get the generator
> code converted to python and not to replace the C++ parser.
> Later, alternative parsers could be investigated and perhaps used --
> something based on gcc worries me though because it may not be easy to
> install and use on Windows.

I've had some very good luck auto-generating things based on clang using 
advice written at 
.   It was pretty straightforward to get the needed clang tool chain 
running on windows in spite of some negative comments somewhere about 
that.  I actually was generating cython code from mako templates and 
generating each function by iterating over parsed functions which met 
the desired criteria.  The major elements of PySide which I did not 
cover were the ability to override c++ virtual functions in python and 
the python/c++ object lifespan synchronization.  Both of these are 
non-trivial elements which no naive cython wrapper will resolve.

One annoying issue I had (which may or may not matter) is that compiling 
a certain .h file in our code was an order of magnitude slower with 
clang than with MSVC.  The obvious caveat is that MSVC was likely using 
pre-compiled headers somehow, but I'm 95% certain it was not.  I suspect 
this speed issue is resolvable.

In a nut-shell:  I still working this project, but I'm left very 
impressed with the clang-parser and associated python bindings.  But 
it's a lot of work to recreate PySide based on those notions. (Caveat:  
technically I was iterating over c-structs with function pointers, but I 
believe the clang c++ support is sufficient to iterate over real classes.)


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