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Implement PEP 572: Assignment Expressions #2636

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scoder opened this issue Sep 29, 2018 · 4 comments · Fixed by #3691
Closed

Implement PEP 572: Assignment Expressions #2636

scoder opened this issue Sep 29, 2018 · 4 comments · Fixed by #3691
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feature Python Semantics
Milestone
3.0

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@scoder
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scoder commented Sep 29, 2018

See https://www.python.org/dev/peps/pep-0572

For Cython, this has a couple of consequences:

  • The parser needs to be extended to support the new syntax.
  • Assignments can now happen inside of expressions, which was previously impossible. Several syntax tree transformations assume that they can stop at an ExprNode, which they cannot any more in the future.
  • The control flow analysis needs updating to detect assigned names in expressions and correctly track their usage.
  • An assignment expression would probably always move the assigned expression into a temp variable and continue from there. There may be expressions from that rule (for simple C types) since C also supports assignments in expressions, but that sounds more like an optimisation than a requirement.
@da-woods da-woods mentioned this issue Jun 1, 2020
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@scoder scoder mentioned this issue Jun 9, 2020
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@spmsh
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spmsh commented Jun 18, 2020

Hi Team, is there any update on this one ? is PEP572 supported anytime soon ? Thanks !

@scoder
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scoder commented Jun 18, 2020 via email

da-woods added a commit to da-woods/cython that referenced this issue Jun 18, 2020
@da-woods
Initial attempt at walrus operator/named expressions
39ff2c4 
Will eventually fix cython#2636

At the moment I think the parsing is far too lenient and
the error cases definitely aren't tested properly.

I also suspect (but don't know) that they don't work in fstrings.

Submitted mostly to see how much stuff it inadvertently breaks
da-woods added a commit to da-woods/cython that referenced this issue Jun 18, 2020
@da-woods
Initial attempt at walrus operator/named expressions
4d2724e 
Will eventually fix cython#2636

At the moment I think the parsing is far too lenient and
the error cases definitely aren't tested properly.

I also suspect (but don't know) that they don't work in fstrings.

Submitted mostly to see how much stuff it inadvertently breaks
@da-woods da-woods mentioned this issue Jun 18, 2020
Merged
@ghost ghost mentioned this issue Aug 28, 2020
Closed
@da-woods da-woods mentioned this issue Mar 29, 2021
Closed
cdrini added a commit to cdrini/openlibrary that referenced this issue Sep 15, 2021
@cdrini
Remove walrus operator in update_work.py
5c3f3ab 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Sep 16, 2021
@cdrini
Remove walrus operator in update_work.py
c6df33f 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Sep 24, 2021
@cdrini
Remove walrus operator in update_work.py
da0456f 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Oct 27, 2021
@cdrini
Remove walrus operator in update_work.py
3513379 
Breaking cython ; See cython/cython#2636
@cdrini cdrini mentioned this issue Oct 28, 2021
Merged
cdrini added a commit to cdrini/openlibrary that referenced this issue Oct 29, 2021
@cdrini
Remove walrus operator in update_work.py
a762614 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Oct 29, 2021
@cdrini
Remove walrus operator in update_work.py
2513271 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Nov 2, 2021
@cdrini
Remove walrus operator in update_work.py
533879c 
Breaking cython ; See cython/cython#2636
cdrini added a commit to cdrini/openlibrary that referenced this issue Nov 9, 2021
@cdrini
Remove walrus operator in update_work.py
0e07b83 
Breaking cython ; See cython/cython#2636
@scoder scoder added this to the 3.0 milestone Jan 27, 2022
scoder pushed a commit that referenced this issue Jan 27, 2022
@da-woods
Implement PEP 572: Named/Assignment Expressions (GH-3691)
fe0eeeb 
Closes #2636
@Borketh Borketh mentioned this issue Feb 25, 2022
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@UlrikHjort
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Hi All,
What is the current status regarding adding the assignment expression operator ? Seems to me that all PRs so far had been closed without a fix ?

@scoder
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scoder commented Mar 16, 2022

It's not released yet. Wait for 3.0a11.

@MatthieuDartiailh MatthieuDartiailh mentioned this issue Jul 12, 2022
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walrus operator/named expressions da-woods/cython
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