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Allow named expressions in generator comprehensions#4109

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youknowone merged 2 commits into
RustPython:mainfrom
astral-sh:charlie/named-expr-generator
Aug 21, 2022
Merged

Allow named expressions in generator comprehensions#4109
youknowone merged 2 commits into
RustPython:mainfrom
astral-sh:charlie/named-expr-generator

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@charliermarsh
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@charliermarsh charliermarsh commented Aug 20, 2022

Summary

See: #4108.

I noticed this when trying to parse the CPython codebase itself, which has this test (on which RustPython throws a syntax error):

def test_named_expression_scope_in_genexp(self):
    a = 1
    b = [1, 2, 3, 4]
    genexp = (c := i + a for i in b)

    self.assertNotIn("c", locals())
    for idx, elem in enumerate(genexp):
        self.assertEqual(elem, b[idx] + a)

youknowone
youknowone reviewed Aug 21, 2022
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Looks great! Because we don't have related cpython unittest for this grammer,
Adding a test under extra_tests/snippets/syntax_generator.py will ensure both CPython and RustPython have same behavior

@charliermarsh charliermarsh force-pushed the charlie/named-expr-generator branch from 55cf065 to 32030a0 Compare August 21, 2022 15:07
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charliermarsh commented Aug 21, 2022

Done!

...
test_snippets.py::SampleTestCase::test_rustpython_syntax_generator PASSED
...

youknowone
youknowone approved these changes Aug 21, 2022
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Thank you!

@youknowone youknowone merged commit 1b58f00 into RustPython:main Aug 21, 2022
@youknowone youknowone linked an issue Aug 21, 2022 that may be closed by this pull request
Syntax error with named expressions in generators #4108
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Syntax error with named expressions in generators

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@charliermarsh @youknowone