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

[Juergen Schoenwaelder <[e-mail]>]

On Wed, Aug 30, 2017 at 10:16:30AM +0100, Robert Wilton wrote:
> Hi Andy,
> 
> What I am suggesting makes it easier for readers, because I am a proponent
> of simpler regular expressions that are easy to read and understand.
> 
> For example, I wonder how many YANG model readers would immediately
> comprehend what this pattern statement means:
> 
> pattern "\p{Sc}\p{Zs}?\p{Nd}+\.\p{Nd}{2}"?
> 
> Does allowing such patterns really make it easier for model readers?

This is always difficult to judge but to be fair you have to show how
you express _the same_ (and not a subset) with some other kind of
regular expressions. (My understanding is that \p{Sc} is a currency
symbol.)

> The proposes guidelines obviously make it easier (or at least no harder) for
> tool makers.
> 
> I agree that there is an minor impact to model writers, but really only in
> the sense that the guidelines would be telling them not to use the esoteric
> options of the XML regex syntax that they probably don't know about anyway.

What is 'esoteric' largely depends on your language environment. What
you are saying by 'do not use \p{}' is essentially 'do not use any
unicode long live ASCII'.
 
/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
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