class Crass::Scanner

is no match, `nil` is returned and the pointer is not advanced.
to and including the end of the match, and advances the pointer. If there
Scans the string until the _pattern_ is matched. Returns the substring up

def scan_until(pattern)
  if match = @scanner.scan_until(pattern)
    @pos     += match.size
    @current  = match[-1]
  end
  match
end