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diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst index fd221fc..db5f374 100644 --- a/Doc/library/sys.rst +++ b/Doc/library/sys.rst @@ -616,6 +616,44 @@ always available. Thus ``2.1.0a3`` is hexversion ``0x020100a3``. + +.. data:: implementation + + An object containing the information about the implementation of the + currently running Python interpreter. Its attributes are the those + that all Python implementations must implement. They are described + below. + + *name* is the implementation's identifier, like ``'cpython'``. + + *version* is a named tuple, in the same format as + :data:`sys.version_info`. It represents the version of the Python + *implementation*. This has a distinct meaning from the specific + version of the Python *language* to which the currently running + interpreter conforms, which ``sys.version_info`` represents. For + example, for PyPy 1.8 ``sys.implementation.version`` might be + ``sys.version_info(1, 8, 0, 'final', 0)``, whereas ``sys.version_info`` + would be ``sys.version_info(1, 8, 0, 'final', 0)``. For CPython they + are the same value, since it is the reference implementation. + + *hexversion* is the implementation version in hexadecimal format, like + :data:`sys.hexversion`. + + *cache_tag* is the tag used by the import machinery in the filenames of + cached modules. By convention, it would be a composite of the + implementation's name and version, like ``'cpython-33'``. However, a + Python implementation may use some other value if appropriate. If + ``cache_tag`` is set to ``None``, it indicates that module caching should + be disabled. + + Regardless of its contents, :data:`sys.implementation` will not + change during a run of the interpreter, nor between implementation + versions. (It may change between Python language versions, + however.) See `PEP 421` for more information. + + .. versionadded:: 3.3 + + .. data:: int_info A :term:`struct sequence` that holds information about Python's internal |