use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new( qr![^/]+(?=/$)! )->explain;
__END__
The regular expression:

(?-imsx:[^/]+(?=/$))

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  [^/]+                    any character except: '/' (1 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    /                        '/'
----------------------------------------------------------------------
    $                        before an optional \n, and the end of
                             the string
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

[download]
use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new( qr![^/]+(?=/)$! )->explain;
__END__
The regular expression:

(?-imsx:[^/]+(?=/)$)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  [^/]+                    any character except: '/' (1 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    /                        '/'
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

[download]

In reply to Re: regex issue (positive look-ahead) by Anonymous Monk
in thread regex issue (positive look-ahead) by jeanluca

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