boost/python/docstring

Boost.Python supports user-defined docstrings with automatic appending of C++ signatures. These features are enabled by default. The class docstring_options is available to selectively suppress the user-defined docstrings, signatures, or both.

Class `docstring_options`

Controls the appearance of docstrings of wrapped functions and member functions for the life-time of the instance. The instances are noncopyable to eliminate the possibility of surprising side effects.

namespace boost { namespace python {

  class docstring_options : boost::noncopyable
  {
  public:
    docstring_options(bool show_all=true);
    docstring_options(bool show_user_defined, bool show_signatures);
    docstring_options(bool show_user_defined, bool show_py_signatures, bool show_cpp_signatures);
    ~docstring_options();
    void disable_user_defined();
    void enable_user_defined();
    void disable_signatures();
    void enable_signatures();
    void disable_py_signatures();
    void enable_py_signatures();
    void disable_cpp_signatures();
    void enable_cpp_signatures();
    void disable_all();
    void enable_all();
  };
}}

Class dostring_options constructors

docstring_options(bool show_all=true);

Effects: Constructs a docstring_options object which controls the appearance of function and member-function docstrings defined in the code that follows. If show_all is true, both the user-defined docstrings and the automatically generated Python and C++ signatures are shown. If show_all is false the __doc__ attributes are None.

docstring_options(bool show_user_defined, bool show_signatures);

Effects: Constructs a docstring_options object which controls the appearance of function and member-function docstrings defined in the code that follows. Iff show_user_defined is true, the user-defined docstrings are shown. Iff show_signatures is true, Python and C++ signatures are automatically added. If both show_user_defined and show_signatures are false, the __doc__ attributes are None.

docstring_options(bool show_user_defined, bool show_py_signatures, bool show_cpp_signatures);

Effects: Constructs a docstring_options object which controls the appearance of function and member-function docstrings defined in the code that follows. Iff show_user_defined is true, the user-defined docstrings are shown. Iff show_py_signatures is true, Python signatures are automatically added. Iff show_cpp_signatures is true, C++ signatures are automatically added. If all parameters are false, the __doc__ attributes are None.

Class docstring_options destructor

~docstring_options();

Effects: Restores the previous state of the docstring options. In particular, if docstring_options instances are in nested C++ scopes the settings effective in the enclosing scope are restored. If the last docstring_options instance goes out of scope the default "all on" settings are restored.

Class `docstring_options` modifier functions

void disable_user_defined();
void enable_user_defined();
void disable_signatures();
void enable_signatures();
void disable_py_signatures();
void enable_py_signatures();
void disable_cpp_signatures();
void enable_cpp_signatures();
void disable_all();
void enable_all();

These member functions dynamically change the appearance of docstrings in the code that follows. The *_user_defined() and *_signatures() member functions are provided for fine-grained control. The *_all() member functions are convenient shortcuts to manipulate all settings simultaneously.

Example

Docstring options defined at compile time
Selective suppressions
Wrapping from multiple C++ scopes

Docstring options defined at compile time

#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/docstring_options.hpp>

void foo() {}

BOOST_PYTHON_MODULE(demo)
{
    using namespace boost::python;
    docstring_options doc_options(DEMO_DOCSTRING_SHOW_ALL);
    def("foo", foo, "foo doc");
}

If compiled with -DDEMO_DOCSTRING_SHOW_ALL=true:

>>> import demo
>>> print demo.foo.__doc__
foo() -> None : foo doc
C++ signature:
    foo(void) -> void

If compiled with -DDEMO_DOCSTRING_SHOW_ALL=false:

>>> import demo
>>> print demo.foo.__doc__
None

Selective suppressions

#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/args.hpp>
#include <boost/python/docstring_options.hpp>

int foo1(int i) { return i; }
int foo2(long l) { return static_cast<int>(l); }
int foo3(float f) { return static_cast<int>(f); }
int foo4(double d) { return static_cast<int>(d); }

BOOST_PYTHON_MODULE(demo)
{
    using namespace boost::python;
    docstring_options doc_options;
    def("foo1", foo1, arg("i"), "foo1 doc");
    doc_options.disable_user_defined();
    def("foo2", foo2, arg("l"), "foo2 doc");
    doc_options.disable_signatures();
    def("foo3", foo3, arg("f"), "foo3 doc");
    doc_options.enable_user_defined();
    def("foo4", foo4, arg("d"), "foo4 doc");
    doc_options.enable_py_signatures();
    def("foo5", foo4, arg("d"), "foo5 doc");
    doc_options.disable_py_signatures();
    doc_options.enable_cpp_signatures();
    def("foo6", foo4, arg("d"), "foo6 doc");
}

Python code:

>>> import demo
>>> print demo.foo1.__doc__
foo1( (int)i) -> int : foo1 doc
C++ signature:
    foo1(int i) -> int
>>> print demo.foo2.__doc__
foo2( (int)l) -> int :
C++ signature:
    foo2(long l) -> int
>>> print demo.foo3.__doc__
None
>>> print demo.foo4.__doc__
foo4 doc
>>> print demo.foo5.__doc__
foo5( (float)d) -> int : foo5 doc
>>> print demo.foo6.__doc__
foo6 doc
C++ signature:
    foo6(double d) -> int

Wrapping from multiple C++ scopes

#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/args.hpp>
#include <boost/python/docstring_options.hpp>

int foo1(int i) { return i; }
int foo2(long l) { return static_cast<int>(l); }

int bar1(int i) { return i; }
int bar2(long l) { return static_cast<int>(l); }

namespace {

    void wrap_foos()
    {
        using namespace boost::python;
        // no docstring_options here
        //   -> settings from outer C++ scope are in effect
        def("foo1", foo1, arg("i"), "foo1 doc");
        def("foo2", foo2, arg("l"), "foo2 doc");
    }

    void wrap_bars()
    {
        using namespace boost::python;
        bool show_user_defined = true;
        bool show_signatures = false;
        docstring_options doc_options(show_user_defined, show_signatures);
        def("bar1", bar1, arg("i"), "bar1 doc");
        def("bar2", bar2, arg("l"), "bar2 doc");
    }
}

BOOST_PYTHON_MODULE(demo)
{
    boost::python::docstring_options doc_options(false);
    wrap_foos();
    wrap_bars();
}

Python code:

>>> import demo
>>> print demo.foo1.__doc__
None
>>> print demo.foo2.__doc__
None
>>> print demo.bar1.__doc__
bar1 doc
>>> print demo.bar2.__doc__
bar2 doc