Kaydet (Commit) 410d3207 authored tarafından R David Murray's avatar R David Murray

whatsnew: XMLPullParser, plus some doc updates.

I was confused by the text saying that read_events "iterated", since it
actually returns an iterator (that's what a generator does) that the
caller must then iterate.  So I tidied up the language.  I'm not sure
what the sentence "Events provided in a previous call to read_events()
will not be yielded again." is trying to convey, so I didn't try to fix that.

Also fixed a couple more news items.
üst aed5b22e
......@@ -105,12 +105,15 @@ Children are nested, and we can access specific child nodes by index::
>>> root[0][1].text
'2008'
.. _elementtree-pull-parsing:
Pull API for non-blocking parsing
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Most parsing functions provided by this module require to read the whole
document at once before returning any result. It is possible to use a
:class:`XMLParser` and feed data into it incrementally, but it's a push API that
Most parsing functions provided by this module require the whole document
to be read at once before returning any result. It is possible to use an
:class:`XMLParser` and feed data into it incrementally, but it is a push API that
calls methods on a callback target, which is too low-level and inconvenient for
most needs. Sometimes what the user really wants is to be able to parse XML
incrementally, without blocking operations, while enjoying the convenience of
......@@ -119,7 +122,7 @@ fully constructed :class:`Element` objects.
The most powerful tool for doing this is :class:`XMLPullParser`. It does not
require a blocking read to obtain the XML data, and is instead fed with data
incrementally with :meth:`XMLPullParser.feed` calls. To get the parsed XML
elements, call :meth:`XMLPullParser.read_events`. Here's an example::
elements, call :meth:`XMLPullParser.read_events`. Here is an example::
>>> parser = ET.XMLPullParser(['start', 'end'])
>>> parser.feed('<mytag>sometext')
......@@ -1038,15 +1041,17 @@ XMLPullParser Objects
.. method:: read_events()
Iterate over the events which have been encountered in the data fed to the
parser. This method yields ``(event, elem)`` pairs, where *event* is a
Return an iterator over the events which have been encountered in the
data fed to the
parser. The iterator yields ``(event, elem)`` pairs, where *event* is a
string representing the type of event (e.g. ``"end"``) and *elem* is the
encountered :class:`Element` object.
Events provided in a previous call to :meth:`read_events` will not be
yielded again. As events are consumed from the internal queue only as
they are retrieved from the iterator, multiple readers calling
:meth:`read_events` in parallel will have unpredictable results.
yielded again. Events are consumed from the internal queue only when
they are retrieved from the iterator, so multiple readers iterating in
parallel over iterators obtained from :meth:`read_events` will have
unpredictable results.
.. note::
......
......@@ -1088,9 +1088,10 @@ Richard Oudkerk in :issue:`15528`)
xml.etree
---------
Add an event-driven parser for non-blocking applications,
:class:`~xml.etree.ElementTree.XMLPullParser`.
(Contributed by Antoine Pitrou in :issue:`17741`.)
A new parser, :class:`~xml.etree.ElementTree.XMLPullParser`, allows a
non-blocking applications to parse XML documents. An example can be
seen at :ref:`elementtree-pull-parsing`. (Contributed by Antoine
Pitrou in :issue:`17741`.)
The :mod:`xml.etree.ElementTree` :func:`~xml.etree.ElementTree.tostring` and
:func:`~xml.etree.ElementTree.tostringlist` functions, and the
......
......@@ -1251,7 +1251,7 @@ class XMLPullParser:
self._close_and_return_root()
def read_events(self):
"""Iterate over currently available (event, elem) pairs.
"""Return an iterator over currently available (event, elem) pairs.
Events are consumed from the internal event queue as they are
retrieved from the iterator.
......
......@@ -2193,14 +2193,14 @@ Library
- Issue #17555: Fix ForkAwareThreadLock so that size of after fork
registry does not grow exponentially with generation of process.
- Issue #17707: multiprocessing.Queue's get() method does not block for short
timeouts.
- Issue #17707: fix regression in multiprocessing.Queue's get() method where
it did not block for short timeouts.
- Isuse #17720: Fix the Python implementation of pickle.Unpickler to correctly
- Issue #17720: Fix the Python implementation of pickle.Unpickler to correctly
process the APPENDS opcode when it is used on non-list objects.
- Issue #17012: shutil.which() no longer fallbacks to the PATH environment
variable if empty path argument is specified. Patch by Serhiy Storchaka.
- Issue #17012: shutil.which() no longer falls back to the PATH environment
variable if an empty path argument is specified. Patch by Serhiy Storchaka.
- Issue #17710: Fix pickle raising a SystemError on bogus input.
......
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