[issue20739] PEP 463 (except expression) implementation

Changes by Berker Peksag : -- resolution: -> rejected stage: patch review -> resolved status: open -> closed ___ Python tracker ___ _

[issue20739] PEP 463 (except expression) implementation

Berker Peksag added the comment: Guido's comment about the PEP is at https://mail.python.org/pipermail/python-dev/2014-March/133118.html Can we close this and mark PEP 463 as rejected now? -- nosy: +berker.peksag ___ Python tracker

[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

Thomas Wouters added the comment: The implementation in the patch preserves the exception context. It's probably the thing that took the most code, and it's why there's two new opcodes in the patch :) It's covered in the tests, too. -- ___ Python tr

[issue20739] PEP 463 (except expression) implementation

Josh Rosenberg added the comment: It's not part of the PEP, but what happens with the new syntax if there is an existing exception context? Some utilities (e.g. functools.lru_cache) use dict.get over a try/except because they operate under the assumption that they may be invoked within an exce

[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

Chris Angelico added the comment: I've applied all the changes my script can find, including ones that are actually quite inappropriate, like: try: some_function_call() except some_exception: some_other_function_call() All tests pass except for one, which I don't fully

[issue20739] PEP 463 (except expression) implementation

Chris Angelico added the comment: One test failing, due to Tools/parser/unparse.py not knowing how to unparse an except expression. Otherwise, test suite passes (with most of the stdlib unchanged). I'm about to try writing an actual conversion script which will rewrite the stdlib, and then see

[issue20739] PEP 463 (except expression) implementation

Changes by Thomas Wouters : Added file: http://bugs.python.org/file34205/5c078eb8da39.diff ___ Python tracker ___ ___ Python-bugs-list mailing

[issue20739] PEP 463 (except expression) implementation

Thomas Wouters added the comment: http://hg.python.org/features/pep-463-except-expr now contains a version of the patch that makes the parentheses mandatory, similar to generator expressions. (Leaving the old patch for reference.) -- hgrepos: +218 _

[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

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[issue20739] PEP 463 (except expression) implementation

New submission from Thomas Wouters: Here is a preliminary implementation of PEP 463, minus mandatory parentheses and with the most straightforward precedence rule: equal to if-expr -- which means this: A if C else B except E: D is parsed as A if C else (B except E: D) (because of associativ