On Tue, 23 Jun 2020 at 17:07, Guido van Rossum firstname.lastname@example.org wrote:
I'm happy to present a new PEP for the python-dev community to review. This is joint work with Brandt Bucher, Tobias Kohn, Ivan Levkivskyi and Talin.
Many people have thought about extending Python with a form of pattern matching similar to that found in Scala, Rust, F#, Haskell and other languages with a functional flavor. The topic has come up regularly on python-ideas (most recently yesterday :-).
I'll mostly let the PEP speak for itself:
- Published: https://www.python.org/dev/peps/pep-0622/ (*)
- Source: https://github.com/python/peps/blob/master/pep-0622.rst
(*) The published version will hopefully be available soon.
I want to clarify that the design space for such a match statement is enormous. For many key decisions the authors have clashed, in some cases we have gone back and forth several times, and a few uncomfortable compromises were struck. It is quite possible that some major design decisions will have to be revisited before this PEP can be accepted. Nevertheless, we're happy with the current proposal, and we have provided ample discussion in the PEP under the headings of Rejected Ideas and Deferred Ideas. Please read those before proposing changes!
I'd like to end with the contents of the README of the repo where we've worked on the draft, which is shorter and gives a gentler introduction than the PEP itself:
I'm just going to say that I *really* like the look of this proposal. I suspect there's going to be a fairly extensive, and detailed, discussion over some of the edge cases, but they can be worked out. Overall, though, I love the general idea.
I'll hold off on saying anything more until I've read the PEP properly. In particular, the "Deferred Ideas" section seems to cover a lot of my initial "what about X" questions. Paul