Re: check the type of the $pattern argument to a regul

ah, hadn't thought of that, no doubt due to my poor command of
regular expressions, so it should be implemented as probably a
recursive function that checks the various steps of the regex.

I *think* David's point is that the problem is mathematically insoluble: the
grammar for regular expressions is recursive, and regular expressions are
not powerful enough to process a language whose grammar is recursive.

Sorry I suggested it!

Michael Kay
http://www.saxonica.com/

> -----Original Message-----
> From: bryan rasmussen [mailto:rasmussen.bryan@xxxxxxxxx]
> Sent: 15 April 2007 09:45
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  check the type of the $pattern argument to
> a regular expression?
>
> I thought that was the most likely solution, although it
> might be that one would want to break the task into a
> template and a number of regular expressions, anyway I was
> wondering if anyone knew of such a solution already?
>
> cheers,
> Bryan Rasmussen
>
> On 4/15/07, David Carlisle <davidc@xxxxxxxxx> wrote:
> >
> > > Short of writing a regular expression that only matches valid
> > > regular expressions (which sounds like an interesting
> exercise for
> > > the reader),
> >
> > along with other interesting exercises like trisecting angles and
> > squaring the circle, presumably:-)
> >
> > David