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PEP 617: Mark as Final (#3596)

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Hugo van Kemenade 2023-12-18 23:25:40 +02:00 committed by GitHub
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@ -4,13 +4,14 @@ Author: Guido van Rossum <guido@python.org>,
Pablo Galindo <pablogsal@python.org>,
Lysandros Nikolaou <lisandrosnik@gmail.com>
Discussions-To: python-dev@python.org
Status: Accepted
Status: Final
Type: Standards Track
Content-Type: text/x-rst
Created: 24-Mar-2020
Python-Version: 3.9
Post-History: 02-Apr-2020
.. canonical-doc:: `the full grammar specification <https://docs.python.org/3/reference/grammar.html>`__
.. highlight:: PEG
========
@ -184,7 +185,7 @@ is, the collection of all valid Python programs).
Similar workarounds appear in multiple other rules of the current grammar.
Sometimes this problem is unsolvable. For instance, `bpo-12782: Multiple context
expressions do not support parentheses for continuation across lines
<http://bugs.python.org/issue12782>`_ shows how making an LL(1) rule that supports
<https://github.com/python/cpython/issues/56991>`_ shows how making an LL(1) rule that supports
writing::
with (
@ -254,7 +255,7 @@ the code in the CST production is reused in the module). Which is worse: the who
tree is kept in memory, keeping many branches that consist of chains of nodes with
a single child. This has been shown to consume a considerable amount of memory (for
instance in `bpo-26415: Excessive peak memory consumption by the Python
parser <https://bugs.python.org/issue26415>`_).
parser <https://github.com/python/cpython/issues/70603>`_).
Having to produce an intermediate result between the grammar and the AST is not only
undesirable but also makes the AST generation step much more complicated, raising
@ -715,7 +716,9 @@ taking the median of three runs. No particular care was taken to stop
other applications running on the same machine.
The first timings are for our canonical test file, which has 100,000
lines endlessly repeating the following three lines::
lines endlessly repeating the following three lines:
.. code-block:: python
1 + 2 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + ((((((11 * 12 * 13 * 14 * 15 + 16 * 17 + 18 * 19 * 20))))))
2*3 + 4*5*6