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PEP 572: Mention another rejected syntax

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Chris Angelico 2018-04-13 22:40:36 +10:00
parent ed718f5186
commit cf7e061167
1 changed files with 13 additions and 2 deletions
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pep-0572.rst
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@ -297,7 +297,18 @@ Broadly the same semantics as the current proposal, but spelled differently.
``with`` and ``except`` statements, where a nearly-identical syntax has ``with`` and ``except`` statements, where a nearly-identical syntax has
different semantics). different semantics).
2. Adorning statement-local names with a leading dot:: 2. ``EXPR -> NAME``::
stuff = [[f(x) -> y, x/y] for x in range(5)]
This syntax is inspired by languages such as R and Haskell, and some
programmable calculators. (Note that a left-facing arrow ``y <- f(x)`` is
not possible in Python, as it would be interpreted as less-than and unary
minus.) This syntax has a slight advantage over 'as' in that it does not
conflict with ``with`` and ``except`` statements, but otherwise is
equivalent.
3. Adorning statement-local names with a leading dot::
stuff = [[(f(x) as .y), x/.y] for x in range(5)] # with "as" stuff = [[(f(x) as .y), x/.y] for x in range(5)] # with "as"
stuff = [[(.y := f(x)), x/.y] for x in range(5)] # with ":=" stuff = [[(.y := f(x)), x/.y] for x in range(5)] # with ":="
@ -309,7 +320,7 @@ Broadly the same semantics as the current proposal, but spelled differently.
become the current recommendation if its advantages are found to outweigh become the current recommendation if its advantages are found to outweigh
its cost. its cost.
3. Adding a ``where:`` to any statement to create local name bindings:: 4. Adding a ``where:`` to any statement to create local name bindings::
value = x**2 + 2*x where: value = x**2 + 2*x where:
x = spam(1, 4, 7, q) x = spam(1, 4, 7, q)