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GeezerVison is showing github.com — gh-135676: Reword the f-string (and t-string) section by encukou · Pull Request #137469 · python/cpython

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@encukou

@encukou encukou commented Aug 6, 2025 •
edited by github-actions Bot
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Continuing from #135942, this tackles the f-string section.

Much of the information was duplicated in stdtypes.rst; this PR keeps lexical/syntactical details in Lexical Analysis and the evaluation & runtime behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the grammar for the two is equivalent, that section was moved to Standard types almost entirely.

  • Issue: Reword the Lexical Analysis chapter of the docs #135676

📚 Documentation preview 📚: https://cpython-previews--137469.org.readthedocs.build/

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encukou and others added 18 commits June 25, 2025 16:27
@encukou @blaisep
WIP: String literals
d4381aa 
Co-authored-by: Blaise Pabon <[email protected]>
@encukou
Use correct Pygments lexer for plain text
80ad85c
@encukou
WIP
e44fa66
@encukou
More WIP
86bf94b
@encukou
Byte strings, raw strings; f-string stub
faf05a1
@encukou
Remove outdated comment
687fe58
@encukou
Fix ReST errors
9f9d29c
@encukou
TMP
1e0c84a
@encukou
Continue with f-strings
e7b57b5
@encukou
Merge in the main branch
3733e0c
@encukou
Work on the f-string semantics
d593940
@encukou
Work on f-strings
0d8a917
@encukou
Merge in the main branch
366ecfc
@encukou @AA-Turner @blaisep
Details & start on the formal grammar
5fdb129 
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Blaise Pabon <[email protected]>
@encukou
Improve text on whitespace in f-string debug expressions
e88843c
@encukou
Merge in the main branch
394f835
@encukou
Comment on the funkiness of the t-string grammar
f2db8f9
@encukou
Adjust t-string docs: move evaluation rules out, add a note on grammar
6468a97
@encukou
encukou requested review from AA-Turner and willingc as code owners August 6, 2025 15:20
@bedevere-app bedevere-app Bot added awaiting core review docs Documentation in the Doc dir skip news labels Aug 6, 2025
@github-project-automation github-project-automation Bot added this to Docs PRs Aug 6, 2025
@github-project-automation github-project-automation Bot moved this to Todo in Docs PRs Aug 6, 2025
@bedevere-app bedevere-app Bot mentioned this pull request Aug 6, 2025
Reword the Lexical Analysis chapter of the docs #135676
Open
StanFromIreland
StanFromIreland reviewed Aug 6, 2025
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Comment thread Doc/library/stdtypes.rst Resolved

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StanFromIreland
StanFromIreland reviewed Aug 6, 2025
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Comment thread Doc/library/stdtypes.rst Resolved

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Comment thread Doc/library/stdtypes.rst Resolved

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@encukou encukou mentioned this pull request Aug 12, 2025
f-string documentation not fully accurate #81997
Closed
@StanFromIreland StanFromIreland linked an issue Aug 12, 2025 that may be closed by this pull request
f-string documentation not fully accurate #81997
Closed
@bedevere-app bedevere-app Bot added awaiting changes and removed awaiting core review labels Oct 8, 2025
@bedevere-app

bedevere-app Bot commented Oct 8, 2025

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When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

And if you don't make the requested changes, you will be put in the comfy chair!
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@encukou

encukou commented Oct 8, 2025

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The question is: Does this PR bring the docs closer to the desired state? Would you be OK with basing your PR on this rather than the status quo?

I did try to move runtime stuff to stdtypes and lexical stuff to lexical_analysis, but yeah, this can always be improved.
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@ericvsmith

ericvsmith commented Oct 8, 2025

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This PR addresses #125496. I've closed that issue in preference to this one.
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@encukou

encukou commented Oct 29, 2025

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@AA-Turner: Would it make sense for you to work on top of this PR?
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@encukou

encukou commented Nov 26, 2025

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I plan to to merge this next week if there are no objections.
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willingc
willingc reviewed Nov 26, 2025
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Comment thread Doc/library/stdtypes.rst
>>> nationality = 'Spanish'
>>> f'The {nationality} Inquisition!'
'The Spanish Inquisition!'
Whitespace before, inside and after the expression, as well as whitespace

@willingc willingc Nov 26, 2025

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Perhaps highlight a bit. I didn't realize that the whitespace was significant before and after within the {}.

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@encukou encukou Nov 27, 2025

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Do you have a suggestion on how to highlight this?

FWIW, I don't think this is a very important detail, since it only affects formatting of debug output.

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@encukou
encukou dismissed AA-Turner’s stale review December 3, 2025 12:48

Let's not have the perfect be the enemy of the good. Follow-up PRs are always welcome.

@bedevere-app bedevere-app Bot added awaiting review and removed awaiting changes labels Dec 3, 2025
@encukou
Merge branch 'main' into lex-analysis-fstrings
ebe2a6b
@encukou
encukou merged commit aea5531 into python:main Dec 3, 2025
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@github-project-automation github-project-automation Bot moved this from Todo to Done in Docs PRs Dec 3, 2025
@miss-islington-app

miss-islington-app Bot commented Dec 3, 2025

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Thanks @encukou for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖
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@bedevere-app bedevere-app Bot removed the awaiting review label Dec 3, 2025
miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Dec 3, 2025
@encukou @blaisep
@AA-Turner @StanFromIreland @miss-islington
pythongh-135676: Reword the f-string (and t-string) section (pythonGH…
1886791 
…-137469)

Much of the information was duplicated in stdtypes.rst; this PR keeps lexical/syntactical details in Lexical Analysis and the evaluation & runtime behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the grammar for the two is equivalent, that section was moved to Standard types almost entirely.
(cherry picked from commit aea5531)

Co-authored-by: Petr Viktorin <[email protected]>
Co-authored-by: Blaise Pabon <[email protected]>
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Stan Ulbrych <[email protected]>
@bedevere-app

bedevere-app Bot commented Dec 3, 2025

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GH-142227 is a backport of this pull request to the 3.14 branch.
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@bedevere-app bedevere-app Bot removed the needs backport to 3.14 bugs and security fixes label Dec 3, 2025
@encukou encukou added the needs backport to 3.14 bugs and security fixes label Dec 3, 2025
@miss-islington-app

miss-islington-app Bot commented Dec 3, 2025

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Thanks @encukou for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖
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miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Dec 3, 2025
@encukou @blaisep
@AA-Turner @StanFromIreland @miss-islington
pythongh-135676: Reword the f-string (and t-string) section (pythonGH…
baa16b9 
…-137469)

Much of the information was duplicated in stdtypes.rst; this PR keeps lexical/syntactical details in Lexical Analysis and the evaluation & runtime behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the grammar for the two is equivalent, that section was moved to Standard types almost entirely.
(cherry picked from commit aea5531)

Co-authored-by: Petr Viktorin <[email protected]>
Co-authored-by: Blaise Pabon <[email protected]>
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Stan Ulbrych <[email protected]>
@miss-islington-app

miss-islington-app Bot commented Dec 3, 2025

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Sorry @encukou, I had trouble completing the backport.
Please retry by removing and re-adding the "needs backport to 3.14" label.
Please backport backport using cherry_picker on the command line.

cherry_picker aea5531583aaa8bfdf3ebca914e9c694617c3489 3.14
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@miss-islington-app miss-islington-app Bot assigned encukou Dec 3, 2025
@StanFromIreland

StanFromIreland commented Dec 3, 2025 •
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The fail must have due to the GH outage I heard about in the Discord, it successfully cherry-picked but failed to add the comment.
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@StanFromIreland StanFromIreland removed the needs backport to 3.14 bugs and security fixes label Dec 3, 2025
StanFromIreland added a commit to StanFromIreland/cpython that referenced this pull request Dec 3, 2025
@encukou @blaisep
@AA-Turner @StanFromIreland
[3.14] pythongh-135676: Reword the f-string (and t-string) section (p…
dab6cb5 
…ythonGH-137469)

Much of the information was duplicated in stdtypes.rst; this PR keeps lexical/syntactical details in Lexical Analysis and the evaluation & runtime behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the grammar for the two is equivalent, that section was moved to Standard types almost entirely.
(cherry picked from commit aea5531)

Co-authored-by: Petr Viktorin <[email protected]>
Co-authored-by: Blaise Pabon <[email protected]>
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Stan Ulbrych <[email protected]>
@StanFromIreland

StanFromIreland commented Dec 3, 2025

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GH-142227 is a backport of this pull request to the 3.14 branch.
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encukou added a commit that referenced this pull request Dec 4, 2025
@miss-islington @encukou
@blaisep @AA-Turner @StanFromIreland
[3.14] gh-135676: Reword the f-string (and t-string) section (GH-137469…
5611e08 
…) (GH-142227)

Much of the information was duplicated in stdtypes.rst; this PR keeps
lexical/syntactical details in Lexical Analysis and the evaluation & runtime
behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the
grammar for the two is equivalent, that section was moved to Standard types
almost entirely.
(cherry picked from commit aea5531)

Co-authored-by: Petr Viktorin <[email protected]>
Co-authored-by: Blaise Pabon <[email protected]>
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Stan Ulbrych <[email protected]>
StanFromIreland added a commit to StanFromIreland/cpython that referenced this pull request Dec 6, 2025
@encukou @blaisep
@AA-Turner @StanFromIreland
pythongh-135676: Reword the f-string (and t-string) section (pythonGH…
eb4688e 
…-137469)

Much of the information was duplicated in stdtypes.rst; this PR keeps lexical/syntactical details in Lexical Analysis and the evaluation & runtime behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the grammar for the two is equivalent, that section was moved to Standard types almost entirely.

Co-authored-by: Blaise Pabon <[email protected]>
Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Stan Ulbrych <[email protected]>
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@willingc willingc willingc left review comments
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Update the grammar for f-strings on "Lexical analysis" page f-string documentation not fully accurate

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@encukou @ericvsmith @StanFromIreland @willingc @AA-Turner
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