[boost] Regex-User: ISBN validation

From: Detlef (DetlefMarsch_at_[hidden])
Date: 2005-04-04 03:05:52

Hi,

we need to validate ISBN.
With another REGEX-implementation we uses (?=.{13})\d{1,5}( 
|\-)\d{1,7}\1\d{1,6}\1(\d|X).
But this seem not to work.
Only the shorter version "\d{1,5}( |\\-)?\\d{1,7}\\1\\d{1,6}\\1(\d|X)" 
works, but how to check the 13 digits?

Thanx in advanced
Detlef