Re: Pattern bug on (a*|)~^(*b)

[Johan Grande <nahoj@crans.org>]

Le 01/08/2023 à 15:30, Peter Stephenson a écrit :
> On 01/08/2023 14:19 Johan Grande <nahoj@crans.org> wrote:
>> So I'm thinking I could filter for user-provided patterns that contain
>> '|' and don't put them in the mega-pattern but filter for them
>> post-globbing. Does that sound like a sound solution to you?
> 
> Yes, I think that would be OK.  The only case I definitely know of where
> you'd hit the problem would be branches using that specific syntax.
> I'm not entirely sure if you'd get issues with approximation, which is
> even more complicated, but so long as there are no (#a...)'s in your
> patterns that's not a problem.
> 
> If you can guarantee that the first branch is a longer match than the
> second, you'll also get a away with it.  So (a*|) will work, because
> the first branch must be at least 1 character, and the second can't
> have any.  Obviously, that's harder to check for automatically, though,
> but you could do a limited check, say, that any | was followed by a
> right parenthesis.

Understood, thank you.

-- 
Johan