[Bro-Dev] patterns and &&/|| vs. &/| operators

Johanna Amann johanna at icir.org
Wed Jun 20 11:22:51 PDT 2018

On Tue, Jun 19, 2018 at 11:21:10AM -0700, Vern Paxson wrote:
> In working on adding bitwise &/| operators for counts, I've come across
> apparently undocumented && and || operators for patterns:
> 	p1 && p2 yields a pattern that matches a p1 followed by a p2
> 	p1 || p2 yields a pattern that matches either p1 or p2
> Confusingly, Bro also supports "p1 | p2", which means the same as "p1 || p2"
> above, but *only* if p1 and p2 are literal patterns, not if they are
> variables of type "pattern".  (This functionality is in common use.)
> It doesn't support "p1 & p2" in any form.
> I searched a large corpus of scripts and didn't find any instances of
> "p1 && p2" or "p1 || p2" for literal patterns, so I suspect the current
> feature is basically unused.
> Proposal: as part of adding bitwise &/| operators for counts, I'll
> also implement &/| operators for patterns, and remove the current
> &&/|| functionality.
> This seems pretty straightforward to me - but I've mistakenly thought
> that about other things before! :-P   So if anyone has comments, plz
> speak up ...

Sounds good to me...


More information about the bro-dev mailing list