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Diffstat (limited to 'Doc/glossary.rst')
| -rw-r--r-- | Doc/glossary.rst | 43 |
1 files changed, 32 insertions, 11 deletions
diff --git a/Doc/glossary.rst b/Doc/glossary.rst index 7431545..ec8af62 100644 --- a/Doc/glossary.rst +++ b/Doc/glossary.rst @@ -27,7 +27,7 @@ Glossary :ref:`2to3-reference`. abstract base class - Abstract Base Classes (abbreviated ABCs) complement :term:`duck-typing` by + :ref:`abstract-base-classes` complement :term:`duck-typing` by providing a way to define interfaces when other techniques like :func:`hasattr` would be clumsy. Python comes with many built-in ABCs for data structures (in the :mod:`collections` module), numbers (in the @@ -57,11 +57,14 @@ Glossary bytecode Python source code is compiled into bytecode, the internal representation - of a Python program in the interpreter. The bytecode is also cached in - ``.pyc`` and ``.pyo`` files so that executing the same file is faster the - second time (recompilation from source to bytecode can be avoided). This - "intermediate language" is said to run on a :term:`virtual machine` - that executes the machine code corresponding to each bytecode. + of a Python program in the CPython interpreter. The bytecode is also + cached in ``.pyc`` and ``.pyo`` files so that executing the same file is + faster the second time (recompilation from source to bytecode can be + avoided). This "intermediate language" is said to run on a + :term:`virtual machine` that executes the machine code corresponding to + each bytecode. Do note that bytecodes are not expected to work between + different Python virtual machines, nor to be stable between Python + releases. A list of bytecode instructions can be found in the documentation for :ref:`the dis module <bytecodes>`. @@ -234,6 +237,8 @@ Glossary performs garbage collection via reference counting and a cyclic garbage collector that is able to detect and break reference cycles. + .. index:: single: generator + generator A function which returns an iterator. It looks like a normal function except that it contains :keyword:`yield` statements for producing a series @@ -247,7 +252,7 @@ Glossary .. index:: single: generator expression generator expression - An expression that returns a generator. It looks like a normal expression + An expression that returns an iterator. It looks like a normal expression followed by a :keyword:`for` expression defining a loop variable, range, and an optional :keyword:`if` expression. The combined expression generates values for an enclosing function:: @@ -327,7 +332,7 @@ Glossary slowly. See also :term:`interactive`. iterable - A container object capable of returning its members one at a + An object capable of returning its members one at a time. Examples of iterables include all sequence types (such as :class:`list`, :class:`str`, and :class:`tuple`) and some non-sequence types like :class:`dict` and :class:`file` and objects of any classes you @@ -397,6 +402,12 @@ Glossary the :term:`EAFP` approach and is characterized by the presence of many :keyword:`if` statements. + In a multi-threaded environment, the LBYL approach can risk introducing a + race condition between "the looking" and "the leaping". For example, the + code, ``if key in mapping: return mapping[key]`` can fail if another + thread removes *key* from *mapping* after the test, but before the lookup. + This issue can be solved with locks or by using the EAFP approach. + list A built-in Python :term:`sequence`. Despite its name it is more akin to an array in other languages than to a linked list since access to @@ -417,9 +428,11 @@ Glossary :class:`importlib.abc.Loader` for an :term:`abstract base class`. mapping - A container object (such as :class:`dict`) which supports arbitrary key - lookups using the special method :meth:`__getitem__`. Mappings also - support :meth:`__len__`, :meth:`__iter__`, and :meth:`__contains__`. + A container object that supports arbitrary key lookups and implements the + methods specified in the :class:`Mapping` or :class:`MutableMapping` + :ref:`abstract base classes <abstract-base-classes>`. Examples include + :class:`dict`, :class:`collections.defaultdict`, + :class:`collections.OrderedDict` and :class:`collections.Counter`. metaclass The class of a class. Class definitions create a class name, a class @@ -440,6 +453,14 @@ Glossary its first :term:`argument` (which is usually called ``self``). See :term:`function` and :term:`nested scope`. + method resolution order + Method Resolution Order is the order in which base classes are searched + for a member during lookup. See `The Python 2.3 Method Resolution Order + <http://www.python.org/download/releases/2.3/mro/>`_. + + MRO + See :term:`method resolution order`. + mutable Mutable objects can change their value but keep their :func:`id`. See also :term:`immutable`. |