Subject: bug#58727: 29.0.50; rx doc: Semantics of RX...

From: Mattias Engdegård <[email-masked]>
Date: Sun, 23 Oct 2022 18:14:10 +0200

> The resulting regexps are concatenating like with an implicit `seq'.
> This is not trivial, though: in stringish regexps the repetition
> operators are only unary, and different interpretations would make sense
> for `rx' (implicit `seq', implicit `or').

The rule is implicit concatenation unless specified otherwise; maybe we could say that in the leading paragraph. (`or` is the only place where concatenation isn't done.)

Otherwise I think we should grant our readers some common sense. It's not a formal specification but meant for humans to understand, and I'm quite sure they do.

> Oh, and maybe let's also make more clear that `rx' always cares about
> implicit grouping when necessary.

No, there is no such thing in rx. The manual provides corresponding string-notation constructs for orientation only.
This is important -- rx forms are defined by their semantics, not by what strings they translate to.