(1) the source of the warning
According to perldiag 
%s matches null string many times
    (W regexp) The pattern you've specified would be an infinite loop
    if the regular expression engine didn't specifically check for
    that. See the perlre manpage.

[download]

HTH

_________
broquaint

In reply to Re: Code in regexp by broquaint
in thread Code in regexp by gjb

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