Gotoken wrote:

# Ruby's regexp is extended rather than the theoretical one.  So, this
# problem is solvable in Ruby perhaps.  Indeed, a Perl's regexp for a
# kind of balanced parens, i.e. email address, is known (e.g. appears
# in Jeffrey E. F. Friedl's book).

For the benefit of the uninitiated following this thread, the preceding 
reference to Friedl's book (and references in subsequent posts) are 
references to the Owl book, which is referenced in the back of the 
Thomas-Hunt book.


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(aka "Mastering Regular Expressions: Powerful techniques for Perl and 
Other Tools")

Conrad Schneiker
(This note is unofficial and subject to improvement without notice.)