Author: ph10 Date: To: Zoltán Herczeg CC: pcre-dev@exim.org Subject: Re: [pcre-dev] Remove some restrictions of lookbehind assertions
On Tue, 30 Jul 2019, Zoltán Herczeg wrote:
> > (*MOVE) is a small addition and solves ND's non-atomic assertion
> > requirement. Perhaps we can just start with (*MOVE).
>
> Yes, if we choose this option to implement.
It occurs to me that (*MOVE) gives scope for infinite loops:
(*MARK:X)(?:abc(*MOVE:X))+
That would loop for ever, wouldn't it? It seems rather a dangerous thing
to implement, unless there is some easy way to catch such cases.
I am beginning to agree with you about "non-atomic assertions" not
really being assertions. Perhaps they could be renamed:
(*napla: becomes (*prg: position reset group
(*naplb: becomes (*prgb: position reset group behind
or even abolish (*naplb: altogether. In addition, these must be treated
as normal groups, not as assertion groups. What happens when they are
repeated must be defined - or maybe they should not be allowed to
repeat, because once again that might be an easy way to infinite loops.
> I would like to hear others opinion though.
