ext/pybind11/README.md

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   2
   3 # pybind11 — Seamless operability between C++11 and Python
   4
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  10
  11 **pybind11** is a lightweight header-only library that exposes C++ types in Python
  12 and vice versa, mainly to create Python bindings of existing C++ code. Its
  13 goals and syntax are similar to the excellent
  14 [Boost.Python](http://www.boost.org/doc/libs/1_58_0/libs/python/doc/) library
  15 by David Abrahams: to minimize boilerplate code in traditional extension
  16 modules by inferring type information using compile-time introspection.
  17
  18 The main issue with Boost.Python—and the reason for creating such a similar
  19 project—is Boost. Boost is an enormously large and complex suite of utility
  20 libraries that works with almost every C++ compiler in existence. This
  21 compatibility has its cost: arcane template tricks and workarounds are
  22 necessary to support the oldest and buggiest of compiler specimens. Now that
  23 C++11-compatible compilers are widely available, this heavy machinery has
  24 become an excessively large and unnecessary dependency.
  25
  26 Think of this library as a tiny self-contained version of Boost.Python with
  27 everything stripped away that isn't relevant for binding generation. Without
  28 comments, the core header files only require ~4K lines of code and depend on
  29 Python (2.7 or 3.x, or PyPy2.7 >= 5.7) and the C++ standard library. This
  30 compact implementation was possible thanks to some of the new C++11 language
  31 features (specifically: tuples, lambda functions and variadic templates). Since
  32 its creation, this library has grown beyond Boost.Python in many ways, leading
  33 to dramatically simpler binding code in many common situations.
  34
  35 Tutorial and reference documentation is provided at
  36 [http://pybind11.readthedocs.org/en/master](http://pybind11.readthedocs.org/en/master).
  37 A PDF version of the manual is available
  38 [here](https://media.readthedocs.org/pdf/pybind11/master/pybind11.pdf).
  39
  40 ## Core features
  41 pybind11 can map the following core C++ features to Python
  42
  43 - Functions accepting and returning custom data structures per value, reference, or pointer
  44 - Instance methods and static methods
  45 - Overloaded functions
  46 - Instance attributes and static attributes
  47 - Arbitrary exception types
  48 - Enumerations
  49 - Callbacks
  50 - Iterators and ranges
  51 - Custom operators
  52 - Single and multiple inheritance
  53 - STL data structures
  54 - Smart pointers with reference counting like ``std::shared_ptr``
  55 - Internal references with correct reference counting
  56 - C++ classes with virtual (and pure virtual) methods can be extended in Python
  57
  58 ## Goodies
  59 In addition to the core functionality, pybind11 provides some extra goodies:
  60
  61 - Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.7) are supported with an
  62   implementation-agnostic interface.
  63
  64 - It is possible to bind C++11 lambda functions with captured variables. The
  65   lambda capture data is stored inside the resulting Python function object.
  66
  67 - pybind11 uses C++11 move constructors and move assignment operators whenever
  68   possible to efficiently transfer custom data types.
  69
  70 - It's easy to expose the internal storage of custom data types through
  71   Pythons' buffer protocols. This is handy e.g. for fast conversion between
  72   C++ matrix classes like Eigen and NumPy without expensive copy operations.
  73
  74 - pybind11 can automatically vectorize functions so that they are transparently
  75   applied to all entries of one or more NumPy array arguments.
  76
  77 - Python's slice-based access and assignment operations can be supported with
  78   just a few lines of code.
  79
  80 - Everything is contained in just a few header files; there is no need to link
  81   against any additional libraries.
  82
  83 - Binaries are generally smaller by a factor of at least 2 compared to
  84   equivalent bindings generated by Boost.Python. A recent pybind11 conversion
  85   of PyRosetta, an enormous Boost.Python binding project,
  86   [reported](http://graylab.jhu.edu/RosettaCon2016/PyRosetta-4.pdf) a binary
  87   size reduction of **5.4x** and compile time reduction by **5.8x**.
  88
  89 - Function signatures are precomputed at compile time (using ``constexpr``),
  90   leading to smaller binaries.
  91
  92 - With little extra effort, C++ types can be pickled and unpickled similar to
  93   regular Python objects.
  94
  95 ## Supported compilers
  96
  97 1. Clang/LLVM 3.3 or newer (for Apple Xcode's clang, this is 5.0.0 or newer)
  98 2. GCC 4.8 or newer
  99 3. Microsoft Visual Studio 2015 Update 3 or newer
 100 4. Intel C++ compiler 17 or newer (16 with pybind11 v2.0 and 15 with pybind11 v2.0 and a [workaround](https://github.com/pybind/pybind11/issues/276))
 101 5. Cygwin/GCC (tested on 2.5.1)
 102
 103 ## About
 104
 105 This project was created by [Wenzel Jakob](http://rgl.epfl.ch/people/wjakob).
 106 Significant features and/or improvements to the code were contributed by
 107 Jonas Adler,
 108 Lori A. Burns,
 109 Sylvain Corlay,
 110 Trent Houliston,
 111 Axel Huebl,
 112 @hulucc,
 113 Sergey Lyskov
 114 Johan Mabille,
 115 Tomasz Miąsko,
 116 Dean Moldovan,
 117 Ben Pritchard,
 118 Jason Rhinelander,
 119 Boris Schäling,
 120 Pim Schellart,
 121 Henry Schreiner,
 122 Ivan Smirnov, and
 123 Patrick Stewart.
 124
 125 ### License
 126
 127 pybind11 is provided under a BSD-style license that can be found in the
 128 ``LICENSE`` file. By using, distributing, or contributing to this project,
 129 you agree to the terms and conditions of this license.