On Sat, 31 Oct 2020 at 17:49, Paul Sokolovsky <pmis...@gmail.com> wrote:
> Alternatively, can add "inline guard sigils" for the most common guard
> conditions, which would be equality, period:
>
> match r:
>     case (src, None):
>     case (==c, msg):
>     case (==s, msg):

`==` interacts poorly with other aspects of the pattern syntax (most
notably keywords in class patterns), but PEP 642's identity constraint
expressions would allow:

     match r:
        case (src, ?is None):
            ... # Any src, msg is None
        case (?is c, msg):
            ... # Any msg, src is c
        case (?is s, msg):
            ... # Any msg, src is s

Cheers,
Nick.

-- 
Nick Coghlan   |   ncogh...@gmail.com   |   Brisbane, Australia
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