Is there a good writeup / talk about the implementation of PEP 634?

Documentation
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In particular, I’m interested in learning about pattern matching of classes. Seems like black magic to me.

Of course, the implementation is there but I cannot wrap my head around it without learning some core concepts.

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PEP 634 itself serves as the specification. @brandtbucher gave a talk about this at PyCon US 2022 that might be helpful: Talk - Brandt Bucher: A Perfect Match The history, design, implementation, and future of Python's... - YouTube

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Interesting video, doesn’t cover the interesting examples though…

One example at 16:09 it does cover seems broken:

PATTERN = r"(.*) is (closed|still under investigation)".
match = re.match(PATTERN, "The Case of the Missing Spam is still under investigation.")

match match:
    case case, "closed":
        print (f"Wow, they finally solved (case}!")
    case case, "still under investigation":
        print (f"I wonder when they will solve (case)!")
    case None:
        print ( "Why aren't they looking into this?")

match won’t unpack unless match.groups() is used, but the latter will raise when there is no match (match is None).

I wonder if it could be rewritten for class matching.

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Raymond gave a talk with lots of examples at PyCon Italia 2022: Structural Pattern Matching in the Real World - Raymond Hettinger - YouTube

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Interesting examples there! Makes me wish for someone to put together Structural Pattern Howto for docs.python.org

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As a start, it would seem to me to be a good idea to port the content of PEP 636 - Structural Pattern Matching: Tutorial over to be an actual tutorial in the Python docs. It’s fairly complete and well-written as is, so it would likely just take some mechanical adjustments, I would think.

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There’s a tutorial that is based of PEP 636 in the What’s New of 3.10 What’s New In Python 3.10 — Python 3.13.0a0 documentation