Re: [netmod] Potential additions to rfc6087bis: RegEx guidelines

[Juergen Schoenwaelder <[e-mail]>]

On Tue, Sep 05, 2017 at 06:17:09PM +0100, Robert Wilton wrote:
> 
> > I believe that tools intended for general use should follow the YANG spec
> > literally.
>
> I don't fully agree.  I think that they only need to cover the parts of the
> YANG spec for the models that they are using (or might use). If nobody uses
> Unicode blocks then it doesn't really matter whether a given tool supports
> them or not.  It is always possible to caveat and add support for the
> missing bits later.  E.g. if I was writing a bespoke XPATH implementation
> for YANG then there is probably quite a lot of the XPATH spec that I would
> also leave out as well, and just concentrate on the parts that people
> actually use, or are likely to use.
>

If this is your understanding of standards, why do you want to define
a subset of XSD pattern based on the your observation what is used or
not used? Simply do not implement what you observe is not used. Why do
we need guidelines of constructs not to use so that they are not used?

There are multiple contradictions in your posts, one of them was the
idea of translating unicode matching to ASCII - which simply does not
work. Or the post where you said \d is OK but then later said \d is
not OK since it translates to a large number of numeric characters.
You really need to sort out what you want, what the problem is you are
trying to solve, how you select the subset of XSD pattern etc. Write
and I-D. And at the end, people who only do POSIX regular expressions,
because they come with the standard C library on POSIX systems or
whatever the reason really is, still will either have to continue to
cheat by silently interpreting XSD pattern as POSIX pattern or they
create a proper new statement to at least properly distinguish
different pattern languages.

/js

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