content_type.treetop

module Mail

  grammar ContentType

    include RFC2822
    include RFC2045

    rule content_type
      main_type "/" sub_type param_hashes:(CFWS ";"? parameter CFWS)* {
        def parameters
          param_hashes.elements.map do |param|
            param.parameter.param_hash
          end
        end
      }
    end

    rule main_type
      discrete_type / composite_type
    end

    rule discrete_type
      "text" / "image" / "audio" / "video" / "application" / extension_token
    end

    rule composite_type
      "message" / "multipart" / extension_token
    end

    rule extension_token
      ietf_token / x_token
    end

    rule sub_type
      extension_token / iana_token
    end

    rule parameter
      CFWS? attr:attribute "=" val:value CFWS? {
        def param_hash
          {attr.text_value => val.text_value}
        end
      }
    end

    rule attribute
      token+
    end

    rule value
      quoted_string {
        def text_value
          quoted_content.text_value
        end
      } / (token / [\x3d])+
    end

  end

end