from Hacker News

Python: Acceptance of Pattern Matching – PEP 634

by potomak on 2/9/21, 4:06 AM with 12 comments

• by JNRowe on 2/9/21, 5:05 AM

  Direct links to the PEPs themselves, to perhaps save others a little time.

  Accepted:

  Specification https://www.python.org/dev/peps/pep-0634/

  Motivation and Rationale https://www.python.org/dev/peps/pep-0635/

  Tutorial https://www.python.org/dev/peps/pep-0636/

  Rejected:

  Unused variable syntax https://www.python.org/dev/peps/pep-0640/

  Explicit Pattern Syntax for Structural Pattern Matching https://www.python.org/dev/peps/pep-0642/

• by pansa2 on 2/9/21, 6:17 AM

  It's interesting that pattern matching has been accepted despite a poll showing a majority (65%) of core developers opposed to this particular proposal, and a plurality (44%) opposed to pattern matching altogether.

  https://discuss.python.org/t/gauging-sentiment-on-pattern-ma...

• by pansa2 on 2/9/21, 8:45 AM

  Is it still the case that these two pieces of code have different behaviour?

      match status:
          case 404:
              return "Not found"
  
      not_found = 404
      match status:
          case not_found:
              return "Not found"
  

  IIRC in an earlier proposal, the former would check for equality (`status == 404`) and the latter would perform an assignment (`not_found = status`).