Mailman 3 December 2007 - capi-sig

ANNOUNCE: PyBindGen 0.8
by Gustavo Carneiro March 10, 2022

March 10, 2022

The other day I released PyBindGen 0.8. Main news is that it features a new experimental header file scanner based on pygccxml (i.e., it's similar to py++ in scope, if not in maturity, but does not use boost.pythonunderneath). == What == PyBindGen is a Python module that is geared to generating C/C++ code that binds a C/C++ library for Python. It does so without extensive use of either C++ templates or C pre-processor macros. It has modular handling of C/C++ types, and can be easily extended with Python plugins. The generated code is almost as clean as what a human programmer would write, and does not depend on any library or header files besides Python itself. == Where == https://launchpad.net/pybindgen/ == NEWS == - Support C++ instance attributes through getter/setter methods - Support functions as methods of C++ classes - Support the PyObject* type - Support unsigned int, C strings (char*) (from Mark Lee) - Add basic support for enum types - New experimental automatic module generator based on C/C++ header file scanner and annotations in comments, using pygccxml - Some bug fixes -- Gustavo J. A. M. Carneiro INESC Porto, Telecommunications and Multimedia Unit "The universe is always one step beyond logic." -- Frank Herbert

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Deploying embedded Python
by Andreas Raab Jan. 3, 2008

Jan. 3, 2008

Hi - I'm currently looking into a few deployment issues with our embedded Python interpreter and I'm looking for any information about deploying embedded Python that people may have. Specifically, I'm looking for the following information: 1) How to define a useful subset of the stdlib that can serve as an initial basis for the installation but later allows upgrade to the "full" library if desirable. In other words, I'd like to deploy a small subset of the stdlib to begin with (simply because of size constraints) which may later be extended to a full stdlib if this is desirable. Has someone done this before? I'd love to have a small "Python.zip" cross-platform stdlib surrogate that just gets shipped with the product. If not, what is the right starting point for analyzing the dependencies inside the stdlib? 2) How to isolate the embedded interpreter from environmental effects. I have found that on occasion, the interpreter would pick up "stray" installations which can cause weird problems. Which environmental settings affect the startup of an embedded Python interpreter? How does one work around/remove those dependencies? Is there any information available about how exactly the startup works? What is being read/loaded in which order etc? 3) General advice about deploying embedded Python. Pointers to web sites, general experience (good or bad) etc. are all very welcome. Thanks, - Andreas

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Problem with a sub-module
by Remi K. Dec. 29, 2007

Dec. 29, 2007

Hi everybody, I have two modules: m1 = Py_InitModule3("PySFML", NULL, "Python binding for sfml (Simple Fast Media Library)"); m2 = Py_InitModule("sf", module_methods); Then I add a few classes, like Color, to m2. Then I make the first module contain the second one: PyModule_AddObject(m1, "sf", m2); This way I can do: from PySFML import * MyColor = sf.Color(0,0,0,255) I would like to be able to do this: from PySFML.sf import * MyColor = Color(0,0,0,255) However, it does not work: "ImportError: No module named sf" First, is what i want to do "correct"? I mean, is it non-standard? And if it is correct, how can I do it? Thanks in advance.

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Re: [capi-sig] Constants in classes?
by Remi K. Dec. 27, 2007

Dec. 27, 2007

Thanks for the answer. I did what you told me after the module's initialisation, it compiles well, however when I try to load my module with python it throws the error: TypeError: can't set attributes of built-in/extension type 'sfColor' Any idea? On Dec 27, 2007 12:53 PM, Gustavo Carneiro <gjcarneiro(a)gmail.com> wrote: > On 27/12/2007, Remi K. <remi.k2620(a)gmail.com> wrote: > > > Hello, > > I am currently writing a python wrapper for the C++ SFML library ( > > http://sfml.sourceforge.net). > > I know there is PyModule_AddIntConstant for adding constants to a > > module, > > but how can I add a constant to one of my module's classes? Is there an > > easy > > way to wrap enumerations? > > Any help is appreciated :) > > > Any type is an object: > > PyObject *enum_value = PyInt_FromLong(123); > PyObject_SetAttrString((PyObject *) &FooBar_Type, enum_value); > Py_DECREF(enum_value); > > -- > Gustavo J. A. M. Carneiro > INESC Porto, Telecommunications and Multimedia Unit > "The universe is always one step beyond logic." -- Frank Herbert

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Constants in classes?
by Remi K. Dec. 27, 2007

Dec. 27, 2007

Hello, I am currently writing a python wrapper for the C++ SFML library ( http://sfml.sourceforge.net). I know there is PyModule_AddIntConstant for adding constants to a module, but how can I add a constant to one of my module's classes? Is there an easy way to wrap enumerations? Any help is appreciated :)

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Re: [capi-sig] Deploying embedded Python
by Andreas Raab Dec. 20, 2007

Dec. 20, 2007

Martin Poirier wrote: > We do that for windows version of Blender ( > http://www.blender.org/ ) (other OSes are assumed to > have a full python distro already). > > What we did to select the different modules included > was very arbitrary. We picked the minimal set of > modules that was required by scripts we wanted to ship > with Blender at this point. With passing releases, we > added some more, trying to keep size low (one of the > reasons we don't include the xml parsing modules, > IIRC). > > Currently, this includes os (and its dependencies), > random, webbrowser, threading, struct, tokenize, ... That sounds quite like the approach we'll be taking ;-) I'll check Blender to see how your subset compares to what I have right now. > I really wouldn't recommend the method we used to get > dependency, which was (if memory serves right) a mix > of looking at the sources and trial/error on a test > machine, adding missing dependencies until it worked. Yes, this is one of the reasons why I'm asking. Despite the (rather nice) Python module system there doesn't seem to be much integrity checking for modules, i.e., whether the set of modules you have is logically consistent (if there is, please let me know). I think the only way to test this is to run a test suite and see if it works or not. >> 2) How to isolate the embedded interpreter from >> environmental effects. > > That's an excellent question. I'm not sure if we came > up with a viable solution for that problem either, so > if anybody else would like to pitch in an answer, we'd > appreciate too. I think Anthony's message addresses this problem quite well. >> 3) General advice about deploying embedded Python. >> Pointers to web >> sites, general experience (good or bad) etc. are all >> very welcome. > > From experience, unless you want to limit python input > to things included with the distribution of your > software, I'd say limit the included modules to the > bare minimum, otherwise it's easy to get to a point > where you're pretty much including the whole Python > distro anyway, so might as well ask your users to > install that directly. > > I hope that was a bit helpful. Indeed you were. Thanks a bunch! Cheers, - Andreas

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lamebrain
by Cowing Maslonka Dec. 14, 2007

Dec. 14, 2007

Hola, Virus found in this message, please delete it without futher reading A cheque and a signed photograph arrived on the anything for us. You see i've brought prog enough such circumstancesyelled at the top of their voices,.

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baptizables
by Lajoie Gouker Dec. 13, 2007

Dec. 13, 2007

Guten Tag, Virus found in this message, please delete it without futher reading He nodded. Keep quite quiet, though, and don't to expand into that territory to the north and here?' 'no murder ever took place here,' said.

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Re: [capi-sig] [C++-sig] ANNOUNCE: PyBindGen 0.8
by Gustavo Carneiro Dec. 8, 2007

Dec. 8, 2007

On 08/12/2007, Joseph Lisee <jlisee(a)gmail.com> wrote: > > That is very cool to here I have one concern and a few comments. I am not > sure > what to think of the annotations in the comments. It feel at same time > both a > hack because it replaces a API around your generator It does not really replace the API. Think of PyBindGen as two separate layers: 1. an low level API layer, and 2. header file scanning and annotations, which are built on top of that layer. The first layer would be needed anyway, for code modularity and readability. And the first layer can be used directly; I don't see any problem with that. and elegant because you > don't have to maintain a separate set of files to represent the > wrapping. The > downside of this is that you would have to modify the source of any code > you > would wish to wrap, and that will get quite cumbersome. It is very true. Sometimes you cannot modify the header files you're trying to wrap. On the other hand, experience tells me you can't fully automate wrapping C/C++ code without either 1) strict displine in the C/C++ code, to use certain memory management conventions (e.g. "callee should never take ownership of the objects in parameters"). or 2) the python bindings have extra information not explicit in the C language. Bottom line is, in the real world you cannot fully automate bindings; you need to give the bindings generator extra information besides the header files. Annotations is IMHO a nice way to give that extra information, when you can. Not only it's easier to follow the annotations since they're right next to the API declarations, but it gives information that even C/C++ coders will find useful. How to enter annotations when you can't modify the header files is, however, an open question. I don't have a clear answer yet, and suggestions are welcome. I am also wondering if you have decent support for standard containers? > Something like Boost.Python indexing suite version 2. Right again. PyBindGen does not have that as of yet. I would like to implement it some day. But I don't think it's as hard as it sounds, so don't lose hope just yet :) One question, though, if someone can answer. How does BP indexing suite map e.g. sequence containers? Just convert all elements to a python list? Or does it implement an object that supports iteration and sequence special methods? BTW, there are more limitations in PyBindGen that people should be aware of, such as: - Does not support multiple inheritance (I don't like MI and have no plans to implement it any time soon, unless a patch is brought to me); - Generates a single potentially big C/C++ file, no splitting done as of yet; - No support yet for one module importing definitions from another module; - Definitions nested inside class namespaces not supported (though should not be hard to implement); Thanks for the comments, -- Gustavo J. A. M. Carneiro INESC Porto, Telecommunications and Multimedia Unit "The universe is always one step beyond logic." -- Frank Herbert

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is there a tp_getattr equivalent for module?
by Anton Tropashko Dec. 7, 2007

Dec. 7, 2007

is there a tp_getattr equivalent for module? i want to dynamically check if an object exists in a module space dynamically and return it if it does. currently i have mymodule.getattr("foo") where getattr is my lookup function plugged thru PyMethodDef/Py_ModuleInit i want to be able to access foo directly, like so: mymodule.foo

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How to do C api testing with python
by Vijay Manohar Dec. 3, 2007

Dec. 3, 2007

Hi All, I have been working with python for a month, I have really loved using python for testing different tools and basically in automating the GUI related to windows, and also on web. Now I have a huge task to test in front of me, we are developing an API, and I feel like I have to test the API so that I have to make sure that how well it works in a given typical failure conditions. Can anyone suggest me how to do API testing of C using python. I have searched out in google and only found a link which creates a wrapper around the api and uses. But I would like to test the API in a pythonic way. Any help is really appreciated. with regards, Manohar Gujja

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Can you tell me how to launch Matlab and run M-files from Python?
by Guofu Chen Dec. 3, 2007

Dec. 3, 2007

Hi, I am now implementing a small Python project, what I am going to do is to lunch Matlab and run some M-files, and get some output from Matlab command prompt. This project will be used on both Windows 32 and Linux. I have no idea how to open Matlab from Python! Do I have to make Matlab C/C++ source codes to be Python modules so that they can be called by Python? Any suggestions would be appreciated!

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