extract_reference

# File ext/openssl/lib/openssl/config.rb, line 163
      def extract_reference(value)
        rest = ''
        if m = value.match(/\(([^)]*)\)|\{([^}]*)\}/)
          value = m[1] || m[2]
          rest = m.post_match
        elsif [((, {{].include?(value[0])
          raise ConfigError, "no close brace"
        end
        if m = value.match(/[a-zA-Z0-9_]*(?:::[a-zA-Z0-9_]*)?/)
          return m[0], m.post_match + rest
        else
          raise
        end
      end