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Synchronize glossary with py3k. 

This update includes new entries that apply to 2.7 too, mention of class
decorators, mention of nonlocal, notes about bytecode, markup fixes and
some rewrappings.  Future backports of changes should be slightly
easier.
This commit is contained in:
Éric Araujo 2011-08-19 01:27:00 +02:00
parent 52a5a03498
commit a8f66dd52c
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Doc/glossary.rst
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@ -58,11 +58,14 @@ Glossary
bytecode bytecode
Python source code is compiled into bytecode, the internal representation Python source code is compiled into bytecode, the internal representation
of a Python program in the interpreter. The bytecode is also cached in of a Python program in the CPython interpreter. The bytecode is also
``.pyc`` and ``.pyo`` files so that executing the same file is faster the cached in ``.pyc`` and ``.pyo`` files so that executing the same file is
second time (recompilation from source to bytecode can be avoided). This faster the second time (recompilation from source to bytecode can be
"intermediate language" is said to run on a :term:`virtual machine` avoided). This "intermediate language" is said to run on a
that executes the machine code corresponding to each bytecode. :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 A list of bytecode instructions can be found in the documentation for
:ref:`the dis module <bytecodes>`. :ref:`the dis module <bytecodes>`.
@ -128,8 +131,9 @@ Glossary
def f(...): def f(...):
... ...
See :ref:`the documentation for function definition <function>` for more The same concept exists for classes, but is less commonly used there. See
about decorators. the documentation for :ref:`function definitions <function>` and
:ref:`class definitions <class>` for more about decorators.
descriptor descriptor
Any *new-style* object which defines the methods :meth:`__get__`, Any *new-style* object which defines the methods :meth:`__get__`,
@ -165,8 +169,8 @@ Glossary
well-designed code improves its flexibility by allowing polymorphic well-designed code improves its flexibility by allowing polymorphic
substitution. Duck-typing avoids tests using :func:`type` or substitution. Duck-typing avoids tests using :func:`type` or
:func:`isinstance`. (Note, however, that duck-typing can be complemented :func:`isinstance`. (Note, however, that duck-typing can be complemented
with :term:`abstract base class`\ es.) Instead, it typically employs with :term:`abstract base classes <abstract base class>`.) Instead, it
:func:`hasattr` tests or :term:`EAFP` programming. typically employs :func:`hasattr` tests or :term:`EAFP` programming.
EAFP EAFP
Easier to ask for forgiveness than permission. This common Python coding Easier to ask for forgiveness than permission. This common Python coding
@ -178,17 +182,34 @@ Glossary
expression expression
A piece of syntax which can be evaluated to some value. In other words, A piece of syntax which can be evaluated to some value. In other words,
an expression is an accumulation of expression elements like literals, names, an expression is an accumulation of expression elements like literals,
attribute access, operators or function calls which all return a value. names, attribute access, operators or function calls which all return a
In contrast to many other languages, not all language constructs are expressions. value. In contrast to many other languages, not all language constructs
There are also :term:`statement`\s which cannot be used as expressions, are expressions. There are also :term:`statement`\s which cannot be used
such as :keyword:`print` or :keyword:`if`. Assignments are also statements, as expressions, such as :keyword:`print` or :keyword:`if`. Assignments
not expressions. are also statements, not expressions.
extension module extension module
A module written in C or C++, using Python's C API to interact with the A module written in C or C++, using Python's C API to interact with the
core and with user code. core and with user code.
file object
An object exposing a file-oriented API (with methods such as
:meth:`read()` or :meth:`write()`) to an underlying resource. Depending
on the way it was created, a file object can mediate access to a real
on-disk file or to another other type of storage or communication device
(for example standard input/output, in-memory buffers, sockets, pipes,
etc.). File objects are also called :dfn:`file-like objects` or
:dfn:`streams`.
There are actually three categories of file objects: raw binary files,
buffered binary files and text files. Their interfaces are defined in the
:mod:`io` module. The canonical way to create a file object is by using
the :func:`open` function.
file-like object
A synonym for :term:`file object`.
finder finder
An object that tries to find the :term:`loader` for a module. It must An object that tries to find the :term:`loader` for a module. It must
implement a method named :meth:`find_module`. See :pep:`302` for implement a method named :meth:`find_module`. See :pep:`302` for
@ -335,7 +356,7 @@ Glossary
slowly. See also :term:`interactive`. slowly. See also :term:`interactive`.
iterable 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 time. Examples of iterables include all sequence types (such as
:class:`list`, :class:`str`, and :class:`tuple`) and some non-sequence :class:`list`, :class:`str`, and :class:`tuple`) and some non-sequence
types like :class:`dict` and :class:`file` and objects of any classes you types like :class:`dict` and :class:`file` and objects of any classes you
@ -404,6 +425,12 @@ Glossary
the :term:`EAFP` approach and is characterized by the presence of many the :term:`EAFP` approach and is characterized by the presence of many
:keyword:`if` statements. :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 list
A built-in Python :term:`sequence`. Despite its name it is more akin 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 to an array in other languages than to a linked list since access to
@ -424,7 +451,8 @@ Glossary
mapping mapping
A container object that supports arbitrary key lookups and implements the A container object that supports arbitrary key lookups and implements the
methods specified in the :class:`Mapping` or :class:`MutableMapping` methods specified in the :class:`~collections.Mapping` or
:class:`~collections.MutableMapping`
:ref:`abstract base classes <collections-abstract-base-classes>`. Examples :ref:`abstract base classes <collections-abstract-base-classes>`. Examples
include :class:`dict`, :class:`collections.defaultdict`, include :class:`dict`, :class:`collections.defaultdict`,
:class:`collections.OrderedDict` and :class:`collections.Counter`. :class:`collections.OrderedDict` and :class:`collections.Counter`.
@ -448,6 +476,14 @@ Glossary
its first :term:`argument` (which is usually called ``self``). its first :term:`argument` (which is usually called ``self``).
See :term:`function` and :term:`nested scope`. 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
Mutable objects can change their value but keep their :func:`id`. See Mutable objects can change their value but keep their :func:`id`. See
also :term:`immutable`. also :term:`immutable`.
@ -480,10 +516,11 @@ Glossary
nested scope nested scope
The ability to refer to a variable in an enclosing definition. For The ability to refer to a variable in an enclosing definition. For
instance, a function defined inside another function can refer to instance, a function defined inside another function can refer to
variables in the outer function. Note that nested scopes work only for variables in the outer function. Note that nested scopes by default work
reference and not for assignment which will always write to the innermost only for reference and not for assignment. Local variables both read and
scope. In contrast, local variables both read and write in the innermost write in the innermost scope. Likewise, global variables read and write
scope. Likewise, global variables read and write to the global namespace. to the global namespace. The :keyword:`nonlocal` allows writing to outer
scopes.
new-style class new-style class
Any class which inherits from :class:`object`. This includes all built-in Any class which inherits from :class:`object`. This includes all built-in
@ -506,9 +543,9 @@ Glossary
:term:`argument`. :term:`argument`.
Python 3000 Python 3000
Nickname for the next major Python version, 3.0 (coined long ago Nickname for the Python 3.x release line (coined long ago when the release
when the release of version 3 was something in the distant future.) This of version 3 was something in the distant future.) This is also
is also abbreviated "Py3k". abbreviated "Py3k".
Pythonic Pythonic
An idea or piece of code which closely follows the most common idioms An idea or piece of code which closely follows the most common idioms
@ -531,7 +568,7 @@ Glossary
object drops to zero, it is deallocated. Reference counting is object drops to zero, it is deallocated. Reference counting is
generally not visible to Python code, but it is a key element of the generally not visible to Python code, but it is a key element of the
:term:`CPython` implementation. The :mod:`sys` module defines a :term:`CPython` implementation. The :mod:`sys` module defines a
:func:`getrefcount` function that programmers can call to return the :func:`~sys.getrefcount` function that programmers can call to return the
reference count for a particular object. reference count for a particular object.
__slots__ __slots__
@ -567,7 +604,15 @@ Glossary
statement statement
A statement is part of a suite (a "block" of code). A statement is either A statement is part of a suite (a "block" of code). A statement is either
an :term:`expression` or a one of several constructs with a keyword, such an :term:`expression` or a one of several constructs with a keyword, such
as :keyword:`if`, :keyword:`while` or :keyword:`print`. as :keyword:`if`, :keyword:`while` or :keyword:`for`.
struct sequence
A tuple with named elements. Struct sequences expose an interface similiar
to :term:`named tuple` in that elements can either be accessed either by
index or as an attribute. However, they do not have any of the named tuple
methods like :meth:`~collections.somenamedtuple._make` or
:meth:`~collections.somenamedtuple._asdict`. Examples of struct sequences
include :data:`sys.float_info` and the return value of :func:`os.stat`.
triple-quoted string triple-quoted string
A string which is bound by three instances of either a quotation mark A string which is bound by three instances of either a quotation mark