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diff --git a/ext/pybind11/docs/intro.rst b/ext/pybind11/docs/intro.rst new file mode 100644 index 000000000..429a01cdd --- /dev/null +++ b/ext/pybind11/docs/intro.rst @@ -0,0 +1,93 @@ +.. image:: pybind11-logo.png + +About this project +================== +**pybind11** is a lightweight header-only library that exposes C++ types in Python +and vice versa, mainly to create Python bindings of existing C++ code. Its +goals and syntax are similar to the excellent `Boost.Python`_ library by David +Abrahams: to minimize boilerplate code in traditional extension modules by +inferring type information using compile-time introspection. + +.. _Boost.Python: http://www.boost.org/doc/libs/release/libs/python/doc/index.html + +The main issue with Boost.Python—and the reason for creating such a similar +project—is Boost. Boost is an enormously large and complex suite of utility +libraries that works with almost every C++ compiler in existence. This +compatibility has its cost: arcane template tricks and workarounds are +necessary to support the oldest and buggiest of compiler specimens. Now that +C++11-compatible compilers are widely available, this heavy machinery has +become an excessively large and unnecessary dependency. + +Think of this library as a tiny self-contained version of Boost.Python with +everything stripped away that isn't relevant for binding generation. Without +comments, the core header files only require ~2.5K lines of code and depend on +Python (2.7 or 3.x) and the C++ standard library. This compact implementation +was possible thanks to some of the new C++11 language features (specifically: +tuples, lambda functions and variadic templates). Since its creation, this +library has grown beyond Boost.Python in many ways, leading to dramatically +simpler binding code in many common situations. + +Core features +************* +The following core C++ features can be mapped to Python + +- Functions accepting and returning custom data structures per value, reference, or pointer +- Instance methods and static methods +- Overloaded functions +- Instance attributes and static attributes +- Arbitrary exception types +- Enumerations +- Callbacks +- Iterators and ranges +- Custom operators +- Single and multiple inheritance +- STL data structures +- Iterators and ranges +- Smart pointers with reference counting like ``std::shared_ptr`` +- Internal references with correct reference counting +- C++ classes with virtual (and pure virtual) methods can be extended in Python + +Goodies +******* +In addition to the core functionality, pybind11 provides some extra goodies: + +- It is possible to bind C++11 lambda functions with captured variables. The + lambda capture data is stored inside the resulting Python function object. + +- pybind11 uses C++11 move constructors and move assignment operators whenever + possible to efficiently transfer custom data types. + +- It's easy to expose the internal storage of custom data types through + Pythons' buffer protocols. This is handy e.g. for fast conversion between + C++ matrix classes like Eigen and NumPy without expensive copy operations. + +- pybind11 can automatically vectorize functions so that they are transparently + applied to all entries of one or more NumPy array arguments. + +- Python's slice-based access and assignment operations can be supported with + just a few lines of code. + +- Everything is contained in just a few header files; there is no need to link + against any additional libraries. + +- Binaries are generally smaller by a factor of at least 2 compared to + equivalent bindings generated by Boost.Python. A recent pybind11 conversion + of `PyRosetta`_, an enormous Boost.Python binding project, reported a binary + size reduction of **5.4x** and compile time reduction by **5.8x**. + +- When supported by the compiler, two new C++14 features (relaxed constexpr and + return value deduction) are used to precompute function signatures at compile + time, leading to smaller binaries. + +- With little extra effort, C++ types can be pickled and unpickled similar to + regular Python objects. + +.. _PyRosetta: http://graylab.jhu.edu/RosettaCon2016/PyRosetta-4.pdf + +Supported compilers +******************* + +1. Clang/LLVM (any non-ancient version with C++11 support) +2. GCC (any non-ancient version with C++11 support) +3. Microsoft Visual Studio 2015 or newer +4. Intel C++ compiler v15 or newer |