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PEP 505: mention late-stage proposals for similar additions to Javascript (#1237)

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Tal Einat 2019-12-02 18:58:11 +02:00 committed by Steve Dower
parent 8910a90d15
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pep-0505.rst
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@ -14,8 +14,9 @@ Abstract
Several modern programming languages have so-called "``null``-coalescing" or
"``null``- aware" operators, including C# [1]_, Dart [2]_, Perl, Swift, and PHP
(starting in version 7). These operators provide syntactic sugar for common
patterns involving null references.
(starting in version 7). There are also stage 3 draft proposals for their
addition to ECMAScript (a.k.a. JavaScript) [3]_ [4]_. These operators provide
syntactic sugar for common patterns involving null references.
* The "``null``-coalescing" operator is a binary operator that returns its left
operand if it is not ``null``. Otherwise it returns its right operand.
@ -91,7 +92,7 @@ operators, the right-hand side is not evaluated until the left-hand side is
determined to be ``None``.
The ``??`` operator binds more tightly than other binary operators as most
existing implementations of these do not propagate ``None``s (they will
existing implementations of these do not propagate ``None`` values (they will
typically raise ``TypeError``). Expressions that are known to potentially
result in ``None`` can be substituted for a default value without needing
additional parentheses.
@ -235,7 +236,7 @@ conversion to use ``None``-aware operators may look like.
Standard Library
----------------
Using the ``find-pep505.py`` script[3]_ an analysis of the Python 3.7 standard
Using the ``find-pep505.py`` script[5]_ an analysis of the Python 3.7 standard
library discovered up to 678 code snippets that could be replaced with use of
one of the ``None``-aware operators::
@ -848,7 +849,13 @@ References
.. [2] A Tour of the Dart Language: Operators
(https://www.dartlang.org/docs/dart-up-and-running/ch02.html#operators)
.. [3] Associated scripts
.. [3] Proposal: Nullish Coalescing for JavaScript
(https://github.com/tc39/proposal-nullish-coalescing)
.. [4] Proposal: Optional Chaining for JavaScript
(https://github.com/tc39/proposal-optional-chaining)
.. [5] Associated scripts
(https://github.com/python/peps/tree/master/pep-0505/)
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