Re: [netmod] regular expression flavours (again)

[Juergen Schoenwaelder <[e-mail]>]

On Thu, Jun 13, 2019 at 03:31:49PM +0200, Robert Varga wrote:
> On 12/06/2019 11:25, Juergen Schoenwaelder wrote:
> > That said, they do seem to declare something like
> > oc-ext:regexp-posix; but it would have been much smarter to use for
> > example oc-posix:regex instead of changing the semantics of the
> > pattern statement.
> 
> Yes, this would be preferable, but it has a downside: now you need to
> carry the patterns twice and must make sure they are in sync. If they
> are not, all sorts of implementation-dependent breakage would ensue.

Authors could simply use the YANG pattern statement as it is defined
and there is zero extra cost.

> The differences are far from minor where specification is concerned, but
> they certainly minor in the vast majoritiy of the use cases and most
> users do not even understand REs enough to know they are dealing with a
> maze of twisty flavors, all alike.
> 
> Do we have an easy way of understanding the corpus of pattern arguments
> being 'out there' in real use?
> 
> Can we engineer a workable solution for the general case without getting
> everyone know the differences in RE engines? Something along the lines
> of this:
> https://github.com/openconfig/public/issues/44#issuecomment-501629497
> perhaps?

Please lets not (even with the best intentions) create yet another
regular expression flavour.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <https://www.jacobs-university.de/>