[issue42128] Structural Pattern Matching (PEP 634)

[Andrei Kulakov]

Change by Andrei Kulakov :


--
nosy: +andrei.avk
nosy_count: 13.0 -> 14.0
pull_requests: +25916
pull_request: https://github.com/python/cpython/pull/27384

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Saiyang Gou]

Change by Saiyang Gou :


--
nosy: +gousaiyang
nosy_count: 12.0 -> 13.0
pull_requests: +24335
pull_request: https://github.com/python/cpython/pull/25642

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Change by Brandt Bucher :


--
stage: patch review -> resolved
status: open -> closed

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Batuhan Taskaya  added the comment:

> Actually, I didn't see that there are still 2 open linked PRs. I'll wait 
> until those are merged.

I've moved the AST validator to its own separate issue so feel free to close 
this Brandt!

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Change by Batuhan Taskaya :


--
pull_requests:  -23539

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:


New changeset f84d5a113680c5a6aaaf9130aed7a34d611748ff by Brandt Bucher in 
branch 'master':
bpo-42128: __match_args__ can't be a list anymore (GH-25203)
https://github.com/python/cpython/commit/f84d5a113680c5a6aaaf9130aed7a34d611748ff


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Change by Brandt Bucher :


--
pull_requests: +23942
pull_request: https://github.com/python/cpython/pull/25203

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Ken Jin]

Change by Ken Jin :


--
pull_requests: +23927
pull_request: https://github.com/python/cpython/pull/25185

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Pablo Galindo Salgado  added the comment:


New changeset 08fb8ac99ab03d767aa0f1cfab3573eddf9df018 by Pablo Galindo in 
branch 'master':
bpo-42128: Add 'missing :' syntax error message to match statements (GH-24733)
https://github.com/python/cpython/commit/08fb8ac99ab03d767aa0f1cfab3573eddf9df018


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Actually, I didn't see that there are still 2 open linked PRs. I'll wait until 
those are merged.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

Yeah, feel free to close this issue.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Also, given that pattern matching is now shipped and documented, perhaps this 
issue should be closed? At this point I think dedicated issues are probably 
better for any new bugs/enhancements/etc.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Cool. Today or tomorrow I'll create an issue in Guido's patma repo and we can 
move our discussion there. I'll also create a branch and add you to my fork.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Batuhan Taskaya  added the comment:

> @BTaskaya, do you have any interest in helping me iterate on new AST nodes?

Sure!

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

@BTaskaya, do you have any interest in helping me iterate on new AST nodes?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Yup, I agree we should explore this area further. See my comment here on 
Adrian’s mypy PR:

https://github.com/python/mypy/pull/10191#issuecomment-797841945

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

This does point out that the ast structure is a liability, and we won't be
able to easily change it, since mypy and IIRC many linters use the ast
module. So I think that maybe we need to think more carefully about what
the *proper* ast structure is, rather than what was most convenient for the
initial implementation. (Brandt, I know you are reluctant to change this,
and I don't blame you, but nevertheless I think we should at least think
about this some more so we're not stuck with a sub-optimal "default"
solution. We've already won the war. Let's not lose the battle. :-)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Not a much thought went into that decision, honestly.

The main reason I chose an identifier there was because "as" always stores a 
simple name, so allowing it to potentially be other contexts or expressions 
(which are illegal) just seemed to create complexity. I saw we used simple 
identifiers in many similar places and just went with it.

(As a related note, if mapping patterns had their own AST nodes, I would 
probably choose to represent "**rest" as an optional identifier, rather than a 
keyless value or optional Name.)

If it causes problems for clients of the AST, it's easy to change. But I sort 
of like it a bit better how it is now.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Adrian Freund]

Adrian Freund  added the comment:

Thanks for the response. Looks like I overlooked the imports, global, nonlocal, 
... because I only searched for usages of identifier, but they use lists of 
identifiers.

In that case I agree that it isn't inconsistent.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Batuhan Taskaya  added the comment:

> This seams really inconsistent with the rest of the ast, where identifiers 
> are always wrapped in a ast.Name object. The only other exception to this is 
> ast.Attribute.

import ... as 
from ... import ... as 
try:
   ...
except ... as :
   ...

global 
nonlocal 
x(=...)

All s above are represented as strings. If  is 
guaranteed to be a single name, then it makes sense to just use an identifier 
instead of wrapping it with Name(). The reason that other stuff like "with ... 
as " uses  instead of  is that you can use extended 
assignment targets (such as unpacking a tuple) over there. 

This rule applies to all other stuff, except for NamedExprs. Which I believe it 
is because the restriction might lift in the future, but now they are limited 
to only keep Name()s. 

I don't personally know why Brandt choosed to use identifier, though I'm a +1 
on the current approach.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Adrian Freund]

Adrian Freund  added the comment:

For the last few days I've been working with pattern matching and it's ast for 
a bit, while trying to add support for it to mypy.

During this I noticed an inconsistency in the ast:

ast.MatchAs has an attribute name which is of type identifier (in C) and type 
str (in python).

This seams really inconsistent with the rest of the ast, where identifiers are 
always wrapped in a ast.Name object. The only other exception to this is 
ast.Attribute.

Judging from Grammar/python.gram this seems deliberate:

as_pattern[expr_ty]:
| pattern=or_pattern 'as' target=capture_pattern {
_Py_MatchAs(pattern, target->v.Name.id, EXTRA) }

Could someone shed some light on why MatchAs directly references an identifier 
instead of an ast.Name?

--
nosy: +freundTech

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Change by Batuhan Taskaya :


--
pull_requests: +23539
pull_request: https://github.com/python/cpython/pull/24771

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Pablo Galindo Salgado  added the comment:


New changeset 0632b1012d4dfa81ffef0d686a4710f6134f77a8 by Pablo Galindo in 
branch 'master':
bpo-42128: Add __match_args__ to structseq-based classes (GH-24732)
https://github.com/python/cpython/commit/0632b1012d4dfa81ffef0d686a4710f6134f77a8


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Change by Pablo Galindo Salgado :


--
pull_requests: +23504
pull_request: https://github.com/python/cpython/pull/24733

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Pablo Galindo Salgado  added the comment:

Opened https://github.com/python/cpython/pull/24732

> I'm also not entirely sure how "unnamed fields" work, or what they're used 
> for. Presumably, we'd want to end the __match_args__ tuple upon hitting one 
> of these?

AFAIK, they should be just excluded from __match_args__

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Change by Pablo Galindo Salgado :


--
pull_requests: +23503
pull_request: https://github.com/python/cpython/pull/24732

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Yeah, probably.

I'm not too familiar with the design of those objects... would it make more 
sense to have the implementation be a single descriptor shared by all derived 
types, or should we precompute the tuple of strings when each new type is 
defined?

I'm also not entirely sure how "unnamed fields" work, or what they're used for. 
Presumably we'd want to end the __match_args__ tuple upon hitting one of these?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Raymond Hettinger]

Raymond Hettinger  added the comment:

Should __match_args__ be added to Objects/structseq.c ?

--
nosy: +rhettinger

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

I'm currently working on some performance benchmarks for PEP 634:

https://github.com/brandtbucher/patmaperformance

Hopefully they will help inform future improvements. I already have benchmarks 
for class patterns and mapping patterns, and am still searching for a good 
problem that really stresses all of the different variations of sequence 
patterns. Maybe a generalized Tower of Hanoi or something?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:


New changeset a22bca6b1e2f3dc11a58f3e5ef5c22e26b8a2d80 by Daniel F Moisset in 
branch 'master':
bpo-42128: Add documentation for pattern matching (PEP 634) (#24664)
https://github.com/python/cpython/commit/a22bca6b1e2f3dc11a58f3e5ef5c22e26b8a2d80


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Carol Willing]

Carol Willing  added the comment:


New changeset a8e2615aa885a121b8cf8e9cd07696207356a25a by Pablo Galindo in 
branch 'master':
bpo-42128: Add documentation for the new match-based AST nodes (GH-24673)
https://github.com/python/cpython/commit/a8e2615aa885a121b8cf8e9cd07696207356a25a


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Change by Pablo Galindo Salgado :


--
pull_requests: +23458
pull_request: https://github.com/python/cpython/pull/24673

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Thanks Pablo!

> If you'd like to take it on feel free, if not I'll create a PR next weekend 
> with tests (probably after release, though I believe it is not a blocker as 
> is).

No problem, I'm pretty busy too. Next weekend is fine.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Pablo Galindo Salgado]

Pablo Galindo Salgado  added the comment:

I can pick up the AST docs PR

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Batuhan Taskaya]

Batuhan Taskaya  added the comment:

> @BTaskaya, do you think you'll have time to open a PR with your AST validator 
> this weekend? It looks good to me (assuming tests pass).

Unfortunately not. I believe it still lacks tests for invalid cases, but other 
than that should work. If you'd like to take it on feel free, if not I'll 
create a PR next weekend with tests (probably after release, though I believe 
it is not a blocker as is).

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

@BTaskaya, do you think you'll have time to open a PR with your AST validator 
this weekend? It looks good to me (assuming tests pass).

Also, we should add the AST docs to our documentation to-do list (should be 
just adding entries for ast.Match, ast.MatchAs, ast.MatchOr, and 
ast.match_case).

I'll try to find time to review the open doc PRs today.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Carol Willing]

Carol Willing  added the comment:

Folks, The What's New PR is open now. I've tried to focus more on the data 
type/shape examples over literal example.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Carol Willing]

Change by Carol Willing :


--
pull_requests: +23452
pull_request: https://github.com/python/cpython/pull/24667

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Change by Daniel Moisset :


--
pull_requests: +23450
pull_request: https://github.com/python/cpython/pull/24664

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Daniel Moisset  added the comment:

Thanks @xtreak, I'll make some changes in these sections too. 

The docs are coming along well, there's still some refinement to do in the 
compound statements section (it's there, but looks to big), I'll submit a draft 
PR during the weekend so interested people can review

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Karthikeyan Singaravelan]

Karthikeyan Singaravelan  added the comment:

I am not sure if this was mentioned. There are a couple of places where 
switch/case is mentioned in the docs and it will be good if these places were 
updated to the tutorial or PEP.

https://docs.python.org/3/faq/design.html#why-isn-t-there-a-switch-or-case-statement-in-python
https://docs.python.org/3/tutorial/controlflow.html#if-statements (This is a 
tutorial so linking PEP 634 might be little advanced topic)

Thanks for all the effort into docs.

--
nosy: +xtreak

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:


New changeset 145bf269df3530176f6ebeab1324890ef7070bf8 by Brandt Bucher in 
branch 'master':
bpo-42128: Structural Pattern Matching (PEP 634) (GH-22917)
https://github.com/python/cpython/commit/145bf269df3530176f6ebeab1324890ef7070bf8


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Daniel Moisset  added the comment:

Note: I will NOT write something for "What's New in 3.10" seeing that's in 
progress

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Daniel Moisset  added the comment:

Fyi, I'm looking into the documentation. I think I can have something basic for 
the middle of this week, so it should be ok for March 1st.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Carol Willing]

Carol Willing  added the comment:

Absolutely, I can help do that.

On Fri, Feb 19, 2021 at 9:14 PM Guido van Rossum 
wrote:

>
> Guido van Rossum  added the comment:
>
> Carol, the most urgent thing we have going is to come up with text for
> what's new. I posted a PR that adds my standard "quick" tutorial (
> https://github.com/python/cpython/pull/24588) which is also found in
> Appendix A of PEP 636 (the tutorial PEP -- the specification PEP 634 has a
> different Appendix A :-), but we are worried that this is going to mislead
> people into thinking "Oh, this is a switch with a funny name" -- which is
> exactly what we don't want (see Jake vd Plas Tweet at
> https://twitter.com/jakevdp/status/1359870794877132810). Having stared at
> this for way too long already I think I'm not able to come up with a better
> way to present this *quickly* in a format that's appropriate for What's New
> (concise, highlights only, meant for existing fairly experienced Python
> users). Do you think you can help?
>
> --
>
> ___
> Python tracker 
> 
> ___
> ___
> Python-bugs-list mailing list
> Unsubscribe:
> https://mail.python.org/mailman/options/python-bugs-list/willingc%40gmail.com
>
>

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

Carol, the most urgent thing we have going is to come up with text for
what's new. I posted a PR that adds my standard "quick" tutorial (
https://github.com/python/cpython/pull/24588) which is also found in
Appendix A of PEP 636 (the tutorial PEP -- the specification PEP 634 has a
different Appendix A :-), but we are worried that this is going to mislead
people into thinking "Oh, this is a switch with a funny name" -- which is
exactly what we don't want (see Jake vd Plas Tweet at
https://twitter.com/jakevdp/status/1359870794877132810). Having stared at
this for way too long already I think I'm not able to come up with a better
way to present this *quickly* in a format that's appropriate for What's New
(concise, highlights only, meant for existing fairly experienced Python
users). Do you think you can help?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Carol Willing]

Carol Willing  added the comment:

@Brandt Bucher  @Guido van Rossum
 I'm
finally getting some free time to get the docs workgroup up and running.
I'm happy to help with any docs that you want for alpha and beyond.

On Fri, Feb 19, 2021 at 8:27 PM Guido van Rossum 
wrote:

>
> Guido van Rossum  added the comment:
>
> But seriously, nothing good can come from social media. It's what drove me
> to retire in 2018. Just ignore it please.
>
> --
>
> ___
> Python tracker 
> 
> ___
> ___
> Python-bugs-list mailing list
> Unsubscribe:
> https://mail.python.org/mailman/options/python-bugs-list/willingc%40gmail.com
>
>

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

But seriously, nothing good can come from social media. It's what drove me to 
retire in 2018. Just ignore it please.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

Okay, I see.  Clearly we should have kept the "DWIM" option, aka "If it starts 
with a capital letter, it's a value pattern." :-)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[laurenjl]

laurenjl  added the comment:

> I've seen too many knee-jerk reactions over the past weeks along the lines of 
> "the new switch feature can't handle named constants!".

Here are some that I found interesting:

https://twitter.com/jakevdp/status/1359870794877132810

https://twitter.com/brandon_rhodes/status/1360226108399099909

--
nosy: +laurenjl

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

Let's continue this at https://github.com/python/cpython/pull/24588

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

I understand. I would just like to see something that won't give new Python 
pattern-matching users (read: everybody) the very painful first impression that 
this is a switch. Can we rework it like:

match input().split():
case []:
print("Got nothing!")
case [first]:
print(f"Got one word: {first}")
case [first, last]:
print(f"Got two words: {first} and {last}")
case _:
print("Got more than two words!")

Or something? (Pardon the example, I don't write many tutorials...)

I've seen too many knee-jerk reactions over the past weeks along the lines of 
"the new switch feature can't handle named constants!". My hope is something 
like the above might provide a more accurate, informative intro.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

> It's not a huge deal, but I vote that we either drop or rework the 
> "http_error" examples. I think it gives people a very wrong first impression 
> that makes the rest of the behavior quite surprising.
> 
> Can it be changed to build off of something familiar, like unpacking? I like 
> 636's approach much more.

So 636 Appendix A is identical to the tutorial in the README of the patma repo. 
It uses http errors for the very first example only, which introduces literal 
matching.  The main text of 636 is too long for what's new IMO, and also a bit 
unfinished.  It is meant as a gentle intro.  The Appendix is meant as an intro 
to pattern matching for experienced Python users (the kind of people for whom 
the what's new series of documents is written).  This tutorial takes the user 
from the simplest forms of patterns (literals) via more complex ones (tuples, 
classes) to advanced concepts like nesting patterns, and then just lists a 
whole bunch of other features.  I started with http errors because 404 must be 
the world's famous number by now, well before pi or even 0 and 1. :-)

See for yourself: https://github.com/python/cpython/pull/24588

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Change by Guido van Rossum :


--
pull_requests: +23368
pull_request: https://github.com/python/cpython/pull/24588

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

> Would people be okay if I added the tutorial from Appendix A of PEP 636 to 
> Doc/whatsnew/3.10.rst?

Yes please!

It's not a huge deal, but I vote that we either drop or rework the "http_error" 
examples. I think it gives people a very wrong first impression that makes the 
rest of the behavior quite surprising.

Can it be changed to build off of something familiar, like unpacking? I like 
636's approach much more.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

I don't know who's really in charge of the docs. I suppose the PEP authors
are, collectively, but that runs the risk that we're all expecting the
person to our left in the circle to do it.

Would people be okay if I added the tutorial from Appendix A of PEP 636 to
Doc/whatsnew/3.10.rst? It's a bit shy of 200 lines, which is bigger than
the largest section there currently ("Parenthesized Context Managers" is
about 50 lines) but feels not unreasonable for something that's been the
subject of at least 7 PEPs and reviewed by two consecutive Steering
Councils. :-) The full whatsnew.rst is currently around 1000 lines. FWIW
the longest what's new ever was for 2.7, at 3300 lines. 3.8 was 2200 lines.

Okay, I'll just add the PR and we can take it from there.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

To the folks working on docs:

Does it seem realistic to have something ready by the next alpha (March 1st)? 
I'd like to at least have a What's New entry and a rough draft tutorial by 
then, since we'll probably (hopefully?) have a bunch of users jumping on that 
release.

I can help if needed, since it looks like I'm mostly waiting on more PR review 
through the weekend. Or I can stay out of the way. :)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Daniel Moisset  added the comment:

@Ken: I've invited you to the repo. For tracking the WIP, 
https://github.com/dmoisset/cpython/tree/patma-docs

Do you want to see if you can base the reference/compound_stmts.rst changes in 
PEP 634? I'll try to fit a variant of the Appendix A of PEP 636 into the 
tutorial and make something up for the reference/lexical_analysis.rst (which 
needs  a section of soft keywords which are not in the PEP trilogy. Perhaps I 
can rescue something from PEP 622)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Also, see my msg379831 above. We can't entirely rely on the PEPs, of course, 
but I think we could still get some decent reuse out of them.

BTW, has the new docs WG started up yet? I keep hearing about it every once in 
a while, but I'm not sure if it's fully-formed yet. Could be good to loop them 
in for review and such, if so.

+nosy Carol since I'm pretty sure she's involved with that.

--
nosy: +willingc

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Lysandros Nikolaou]

Lysandros Nikolaou  added the comment:

The grammar is indeed auto-generated by reading the actual Grammar file, 
python.gram. Here's the lexer Pablo had developed for doing the 
syntax-highlighting.

https://github.com/python/cpython/blob/master/Doc/tools/extensions/peg_highlight.py

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Ken Jin]

Ken Jin  added the comment:

Hi Daniel, wow thanks for the offer! My GitHub username is Fidget-Spinner.
I'm not sure about the grammar file either. 
Oh, thanks for mentioning the tutorial recommendation by the SC, I'll keep that 
in mind. 

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Daniel Moisset]

Daniel Moisset  added the comment:

Hey Ken, I was about to take on this myself, but I wouldn't mind a bit of help.

Your list seems ok, I would add to it a section about PM in the python tutorial 
(which was explicitly mentioned in the SC acceptance notice). 

Regarding the grammar, I believe that one is autogenerated from the parser, so 
it's likely that no changes are required there. Correct me if I'm wrong here.

I'll set up a branch in github and add you as a collaborator so we can prepare 
a PR. I'll base the branch of Brandt's implementation PR. If you give me your 
github id I can add you as collaborator so we can work there.

--
nosy: +Daniel Moisset

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Ken Jin]

Ken Jin  added the comment:

Guido and Brandt, may I take a stab at the docs for this? I'll probably base 
most of it off PEP 636's tutorial.

Relevant parts of the docs that I've identified:
reference/lexical_analysis.rst
reference/compound_stmts.rst
reference/grammar.rst

# this probably needs a summarized version for non-technical users
whatsnew/3.10.rst

If I missed anything, please point them out :).

--
nosy: +kj

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

The PEP has been accepted.

I propose that we use separate PRs for docs (and incremental improvements to 
the code) but tie them all together using the same issue number (this will 
require adding "skip news" to later PRs).

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

I'll wait till the SC makes a ruling, then send a message to our docs list (I 
think we have one)? I'm fine coordinating/reviewing that, or making PRs myself 
if nobody else steps up.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Guido van Rossum]

Guido van Rossum  added the comment:

If you feel up to it, you might see if you could open a new, separate
(draft) PR that updates all those docs. (But you could also wait and see if
someone volunteers. There are some good doc writers active ATM.)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Thinking ahead...

A lot of work has gone into writing these PEPs...  we should see how much we 
can easily convert into actual docs. It seems to me:

- Parts of PEP 634 and PEP 635 can be worked into the language reference.

- Guido's overview (the appendix of PEP 636) can probably just be dropped 
verbatim into the What's New for 3.10.

- The rest of PEP 636 can just be lifted into the docs as a proper tutorial and 
linked to from the What's New.

Also, we need to document the stdlib changes (ast, collections, dataclasses, 
keyword, ...). The dis module docs are already part of the implementation.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Change by Brandt Bucher :


--
keywords: +patch
pull_requests: +21846
pull_request: https://github.com/python/cpython/pull/22917

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

Brandt Bucher  added the comment:

Sorry, just resolving some changes with master. Are you parser people finished 
breaking my grammar yet? Sheesh. ;)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42128] Structural Pattern Matching (PEP 634)

[Brandt Bucher]

New submission from Brandt Bucher :

PEP 634 has not yet been accepted, but we'd like to hit the ground running and 
get this into alphas as soon as it (hopefully) is.

Several people have volunteered to review the implementation, since it's so 
huge. Other reviews are very welcome, if anybody has a bit of time to pitch in. 
This touches tons of stuff: the parser, the compiler, the VM, the builtins, the 
stdlib, the tests... I'd like as many eyeballs as possible!

I'll have a draft PR up against master in a few minutes. Let's try to keep all 
of the review comments there.

--
assignee: brandtbucher
components: Interpreter Core
messages: 379442
nosy: BTaskaya, brandtbucher, gvanrossum, lys.nikolaou, pablogsal
priority: normal
severity: normal
stage: patch review
status: open
title: Structural Pattern Matching (PEP 634)
type: enhancement
versions: Python 3.10

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com