bpo-32117: Allow tuple unpacking in return and yield statements by dacut · Pull Request #4509 · python/cpython · GitHub
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bpo-32117: Allow tuple unpacking in return and yield statements #4509

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Merged
gvanrossum merged 6 commits into from
Sep 22, 2018
Merged

bpo-32117: Allow tuple unpacking in return and yield statements #4509

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53ffbdd
Fix return statements to allow unpacking without parenthesis.
dacut Nov 16, 2017
02bd4f0
Fix yield statements to allow unpacking without parenthesis.
dacut Nov 22, 2017
47e3ac3
Add test for yield tuple unpacking.
dacut Nov 22, 2017
31a0c8f
Add news blurb for yield and return tuple unpacking.
dacut Nov 22, 2017
f84da46
Add equality test for tuple unpacking in yield
jChapman Sep 16, 2018
67303ca
Touch up news entry
brettcannon Sep 21, 2018
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4 changes: 2 additions & 2 deletions Grammar/Grammar
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11 changes: 10 additions & 1 deletion Lib/test/test_grammar.py
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Original file line number Diff line number Diff line change
Expand Up @@ -824,11 +824,17 @@ def test_inner(extra_burning_oil = 1, count=0):
test_inner()

def test_return(self):
# 'return' [testlist]
# 'return' [testlist_star_expr]
def g1(): return
def g2(): return 1
def g3():
z = [2, 3]
return 1, *z

g1()
x = g2()
y = g3()
self.assertEqual(y, (1, 2, 3), "unparenthesized star expr return")
check_syntax_error(self, "class foo:return 1")

def test_break_in_finally(self):
Expand Down Expand Up @@ -981,6 +987,9 @@ def g(): f((yield 1))
def g(): f((yield 1), 1)
def g(): f((yield from ()))
def g(): f((yield from ()), 1)
# Do not require parenthesis for tuple unpacking
def g(): rest = 4, 5, 6; yield 1, 2, 3, *rest

@gvanrossum gvanrossum Sep 15, 2018

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I would add another test here to validate that this works, e.g. self.assertEqual(list(g()), [(1, 2, 3, 4, 5, 6)]).

@jChapman jChapman Sep 16, 2018

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I was tempted to do self.assertEqual(*g(), (1, 2, 3, 4, 5, 6)), but I think we're testing enough unpacking

self.assertEquals(list(g()), [(1, 2, 3, 4, 5, 6)])
check_syntax_error(self, "def g(): f(yield 1)")
check_syntax_error(self, "def g(): f(yield 1, 1)")
check_syntax_error(self, "def g(): f(yield from ())")
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2017-11-22-15-43-14.bpo-32117.-vloh8.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Iterable unpacking is now allowed without parenthesis in yield and return
statements, e.g. ``yield 1, 2, 3, *rest``. Thanks to David Cuthbert for the
change and jChapman for added tests.
6 changes: 3 additions & 3 deletions Python/graminit.c
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