clear_comments

# File ext/openssl/lib/openssl/config.rb, line 177
      def clear_comments(line)
        # FCOMMENT
        if m = line.match(/\A([\t\n\f ]*);.*\z/)
          return m[1]
        end
        # COMMENT
        scanned = []
        while m = line.match(/[#'"\\]/)
          scanned << m.pre_match
          c = m[0]
          line = m.post_match
          case c
          when '#'
            line = nil
            break
          when "'", '"'
            regexp = (c == "'") ? QUOTE_REGEXP_SQ : QUOTE_REGEXP_DQ
            scanned << c
            if m = line.match(regexp)
              scanned << m[0]
              line = m.post_match
            else
              scanned << line
              line = nil
              break
            end
          when "\\"
            scanned << c
            scanned << line.slice!(0, 1)
          else
            raise 'must not reaced'
          end
        end
        scanned << line
        scanned.join
      end