XDress 0.3 Release Notes

XDress is an automatic wrapper generator for C/C++ written in pure Python. Currently, xdress may generate Python bindings (via Cython) for C++ classes, functions, and certain variable types. It also contains idiomatic wrappers for C++ standard library containers (sets, vectors, maps). In the future, other tools and bindings will be supported.

The main enabling feature of xdress is a dynamic type system that was designed with the purpose of API generation in mind.

Release highlights:

• C++ template class & function support
• Automatic docstring generation via dOxygen
• A complete type system implementation refactor
• Wrapped names may be different than source names, allowing automatic PEP-8-ification
• A plethora of useful bug fixes

Please visit the website for more information: http://xdress.xyz/

Ask questions on the mailing list: xdress@googlegroups.com

Download the code from GitHub: http://github.com/xdress/xdress

XDress is free & open source (BSD 2-clause license) and requires Python 2.7, NumPy 1.5+, Cython 0.19+, and optionally GCC-XML, pycparser, dOxygen, and lxml.

New Features

C++ Template Support

The most requested feature following SciPy 2013 was full and complete support for C++ templates. It is here! Template instantiations are now automatically discovered, described, and wrapped. The only exception to this is that template member functions are not automatically discovered due to a defect in GCC-XML. Template methods must, therefore, be added by hand in a sidecar file. See the FAQ for more details.

dOxygen Docstrings

A new plugin called xdress.doxygen has been added which automatically scrapes the source code for documentation using dOxygen. These are then automatically inserted as docstrings into the wrappers that are generated. These docstrings follow the numpydoc convention.

Type System Refactor

The type system has undergone a complete reactor to make it more user-friendly and expose a lot of its internals. Previously, the type system was a collection of functions and module-level private containers. All of this has been moved into a new TypeSystem class whose attributes and methods are almost all public. This enables a number of potentially useful features.

• Type systems may be customized in the xdressrc.py file.
• Type systems may be customized in side car files.
• Type systems can now persist and load themselves. This enables saving a type system when wrapping one project and loading it in as a dependency in future projects.
• Easier testing

As a consequence, most other parts of xdress must now hold a reference to a type system object. Before, it was sufficient to import the type system module.

API Named Tuple

A new named tuple class apiname has been added. This allows for a broader selection of how users can choose to write names in the classes, functions, and variables list in the run control file. Possible options now include:

from xdress.utils import apiname
classes = [
    (srcname, srcfile,),
    (srcname, srcfile, tarfile,),
    (srcname, srcfile, tarfile, tarname),
    [srcname, srcfile, tarfile, tarname],
    {'srcname': a, 'srcfile': b, 'tarfile': c, 'tarname': d},
    apiname(srcname, srcfile, tarfile, tarname),
    ]

This allows the target name (ie the name in the wrapper) to be distinct from the name that is in the C/C++ source code (ie the source name). This is very useful for customizing APIs because xdress takes care of the mapping for you!

PEP-8 Compliance Plugin

A new plugin called xdress.pep8names has been added which ensures that all target names for API elements are PEP-8 compliant for that type. If the target name is not PEP-8 complaint then it converts it to a compliant version for you. Subversive? That’s the point! Functions and variables are converted to lowercase_with_underscores while classes are converted to CapCase.

Description Filtering Plugin

Sometimes autoall will expose too much. To avoid certain API elements while still automatically finding other names, the xdress.descfilter plugin allows you to skip methods, attributes, and types that the you doesn’t feel are appropriate to expose. This is also a useful stop-gap for data types that have not yet been implemented into the xdress type system.

Tab Completion in BASH

Through the power and magic of the argcomplete package, all arguments and options for all plugins now have tab-completion enabled in BASH. Install argcomplete and then add the following lines to your ~/.bashrc file:

# Enable completion for xdress
eval "$(register-python-argcomplete xdress)"

Major Bug Fixes

• Enums and functions pointers were noticeably absent from the GCC-XML describer. This has been rectified.
• Classes and structs are now registered into the type system earlier. This allows them to be used in other plugins. This includes stlwrap. It is now possible and easy to create custom numpy dtypes for any struct or C++ class.
• Fixed segfaults with custom dtypes
• Fixed build issue when only vectors were present in stlcontainers.
• The global namespace is now correctly represented by None, rather than ‘::’, when using GCC-XML.

Join in the Fun!

If you are interested in using xdress on your project (and need help), contributing back to xdress, starting up a development team, or writing your own code generation plugin tool, please let us know. Participation is very welcome!

Authors

• Anthony Scopatz
• Spencer Lyon
• John Wiggins *
• Matt McCormick *
• Brad Buran

An * indicates a first time contributor.

Links

1. Homepage - http://xdress.xyz/
2. Mailing List - xdress@googlegroups.com
3. GitHub Organization - https://github.com/xdress
4. numpydoc - https://pypi.python.org/pypi/numpydoc
5. argcomplete - https://argcomplete.readthedocs.org/en/latest/