[C++-SIG] [ANN] Boost Python Library (formerly py_cpp)

David Abrahams abrahams at mediaone.net
Mon Dec 11 01:39:28 CET 2000

I am proud to announce the re-release of py_cpp as the Boost Python Library
at www.boost.org.

Among its many features:

* Automatic function argument type checking and conversion
* Subclassing wrapped C++ types in Python
* [Member] Function overloading
* Automatic wrapping of numeric operators
* Pickling support
* Support for C++ smart pointers

For those who have been following py_cpp, significant improvements have
occurred since the last release. An excerpt from the release notes follows:

2000-11-22 10:00
    Ullrich fixed bug in operator_dispatcher<op_long>.

2000-11-21 10:00
    Changed all class and function names into lower_case.

    Ullrich updated documentation for operator wrapping.

2000-11-20 10:00
    Ullrich renamed ExtensionClass:register_coerce() into
    ExtensionClass:def_standard_coerce() and made it public

    Ullrich improved shared_pod_manager.

2000-11-17 15:04
    Changed allocation strategy of shared_pod_manager to make it portable.

    Added pickling support + tests thanks to "Ralf W. Grosse-Kunstleve"
    <rwgk at cci.lbl.gov>

    Added a specialization of Callback<const char*> to prevent unsafe usage.

    Fixed Ullrich's operator_dispatcher refcount bug

    Removed const char* return values from virtual functions in tests; that
    usage was unsafe.

    Ullrich changed Module::add() so that it steals a reference (fix of
refcount bug)

    Ullrich added operator_dispatcher::create() optimization

    Ullrich changed design and implementation of TypeObjectBase::enable()
(to eliminate low-level
    code) and added shared_pod_manager optimization.

2000-11-15 12:01
    Fixed refcount bugs in operator calls.

    Added callback_adjust_refcount(PyObject*, Type<T>) to account for
different ownership
    semantics of Callback's return types and Caller's arguments (which both
use from_python())
    This bug caused refcount errors during operator calls.

    Moved operator_dispatcher into extclass.cpp
    Gave it shared ownership of the objects it wraps

    Introduced sequence points in extension_class_coerce for


    MixedCase template type argument names

    Changed internal error reporting to use Python exceptions so we don't
force the
    user to link in iostreams code

    Changed error return value of call_cmp to -1

    Moved unwrap_* functions out of operator_dispatcher. This was
transitional: when
    I realized they didn't need to be declared in extclass.h I moved them
out, but
    now that operator_dispatcher itself is in extclass.cpp they could go
back in.

    Numerous formatting tweaks

    Updated the BoundFunction::create() optimization and enabled it so it
could actually be used!

2000-11-15 00:26

    Made Ullrich's operators support work with MSVC

    Cleaned up operators.h such that invalid define_operator<0> is no longer

    Ullrich created operators.h to support wrapping of C++ operators
(including the "__r*__" forms).
    He added several auxiliary classes to extclass.h and extclass.cpp (most
    py::detail::operator_dispatcher and py::operators)

2000-11-13 22:29

    removed obsolete ExtensionClassFromPython for good.

    removed unused class ExtensionType forward declaration

2000-11-12 13:08

    Added enum_as_int_converters for easier enum wrapping

    Introduced new conversion namespace macros:

    callback.h, gen_callback.py:
        Added call() function so that a regular python function (as opposed
         method or other function-as-attribute) can be called.

         Added newlines for readability.

        Fixed a bug in add(), which allows non-method class attributes

    Ullrich has added def_raw for simple varargs and keyword support.

    Fixed version number check for __MWERKS__

    Added tests for enums and non-method class attributes

        Added py::String operator*= and operator* for repetition

        Change Dict::items(), keys(), and values() to return a List

        Added template versions of set_item, etc., methods so that users can
        use C++ types that have to_python() functions as parameters.

        Changed various Ptr by-value parameters to const Ptr&

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