Liberal URL-matching Regex

(?xi)
\b
(                       # Capture 1: entire matched URL
  (?:
    [a-z][\w-]+:            # URL protocol and colon
    (?:
      /{1,3}                    # 1-3 slashes
      |                         #   or
      [a-z0-9%]                 # Single letter or digit or '%'
                                # (Trying not to match e.g. "URI::Escape")
    )
    |                       # or
    (www\d{0,3}[.])             # Capture 2: "www.", "www1.", "www2." … "www999."
  )
  (                     # Capture 3: everything after "http://[www|www1...]"
    (?:                       # One or more:
      [^\s()<>]+                  # Run of non-space, non-()<>
      |                           #   or
      \([^\s()<>]+\)              # a matching set of parens
    )+
    (?:                       # End with:
      \([^\s()<>]+\)                  # a set of parens
      |                               #   or
      [^`!()\[\]{};:'".,<>?«»“”‘’\s]  # not a space or one of these punct chars
    )
  )
)