SCCD/examples/chatclient/model_chatclient.xml

<single_instance_cd>
  <delta>1 ms</delta>

  <statechart>

    <semantics
      big_step_maximality="take_one"
      internal_event_lifeline="reMainder"
      input_event_lifeline="whole"
      enabledness_memory_protocol="small_step"
      assignment_memory_protocol="small_step"
    />

    <datamodel>
      import sccd.action_lang.lib.utils;
      
      import lib.network_client;
      import lib.ui;
      import lib.utils;

      # Statechart's variables
      curr_server = 0;
      room_number = 0;
      reconnecting = False;
    </datamodel>

    <inport name="network">
      <event name="connected"/>
      <event name="disconnected"/>
      <event name="joined"/>
      <event name="left"/>
      <event name="receive_message"/>
      <event name="alive"/>
    </inport>

    <inport name="ui">
      <event name="input"/>
    </inport>

    <outport name="network">
      <event name="connect"/>
      <event name="disconnect"/>
      <event name="join"/>
      <event name="leave"/>
      <event name="send_message"/>
      <event name="poll"/>
    </outport>

    <root>
      <parallel id="P">
        <!-- Main orthogonal region: all user interaction and Main window state -->
        <state id="Main" initial="Connecting">

          <state id="Connecting" initial="Initial">
            <onentry>
              <code> input_command(); </code>
            </onentry>
            <state id="Initial">
              <transition after="100 ms" target="../TryingConnect">
                <code> add_message("trying to connect to server " + get_server(curr_server), "info"); </code>
                <raise event="connect">
                  <param expr="get_server(curr_server)"/>
                </raise>
              </transition>
            </state>
            <state id="TryingConnect">
              <transition event="connected" target="/P/Main/Connected/H">
                <code> add_message("connected to server " + get_server(curr_server), "info"); </code>
              </transition>
              <transition after="5 s" target="../Initial">
                <code>
                  add_message("unable to connect to server " + get_server(curr_server), "info");
                  if (not reconnecting) {
                    curr_server = (curr_server + 1) % get_nr_of_servers();
                  }
                </code>
              </transition>
            </state>
          </state>

          <state id="Connected" initial="LeavingOrLeft">
            <transition event="timeout" target="/P/Main/Connecting">
              <code>
                add_message("disconnected", "info");
                reconnecting = True;
              </code>
            </transition>

            <state id="LeavingOrLeft" initial="NotJoined">
              <state id="NotJoined">
                <transition event="input(char: str)" cond='char == "j"' target="../GettingRoomNumber">
                  <code> input_join(); </code>
                </transition>
              </state>

              <state id="GettingRoomNumber">
                <transition event="input(char: str)" cond="is_backspace(char)" target=".">
                  <code> remove_last_in_buffer(); </code>
                </transition>
                <transition event="input(char: str)" cond="is_enter(char)" target="../../JoiningOrJoined">
                  <code>
                    room_number = stoi(get_buffer());
                    clear_input();
                    input_command();
                  </code>
                </transition>
                <transition event="input(char: str)" cond="is_numerical(char)" target=".">
                  <code> append_to_buffer(char); </code>
                </transition>
                <transition event="input(char: str)" cond="not is_numerical(char)" target=".">
                  <code> add_message("only numerical input allowed!", "warning"); </code>
                </transition>
              </state>

              <state id="Leaving">
                <transition event="left" target="../NotJoined">
                  <code> add_message("left room", "info"); </code>
                </transition>
              </state>
            </state>

            <state id="JoiningOrJoined" initial="Joining">
              <state id="Joining">
                <onentry>
                  <raise event="join">
                    <param expr="room_number"/>
                  </raise>
                </onentry>
                <onexit>
                </onexit>

                <transition event="joined" target="../Joined/H">
                  <code> add_message("joined room " + int_to_str(room_number), "info"); </code>
                </transition>
              </state>

              <state id="Joined" initial="Initial">
                <state id="Initial">
                  <transition event="input(char: str)" cond='char == "m"' target="../EnteringMessage"/>
                  <transition event="input(char: str)" cond='char == "l"' target="/P/Main/Connected/LeavingOrLeft/Leaving">
                    <raise event="leave"/>
                    <code> input_command(); </code>
                  </transition>
                </state>

                <state id="EnteringMessage">
                  <onentry>
                    <code> input_msg(); </code>
                  </onentry>
                  <!-- explicit (document order) priority used here: -->
                  <transition event="input(char: str)" cond="is_backspace(char)" target=".">
                    <code> remove_last_in_buffer(); </code>
                  </transition>
                  <transition event="input(char: str)" cond="is_enter(char)" target="../Initial">
                    <raise event="send_message">
                      <param expr="get_buffer()"/>
                    </raise>
                    <code>
                      add_message(get_buffer(), "local_message");
                      clear_input();
                      input_command();
                    </code>
                  </transition>
                  <transition event="input(char: str)" target=".">
                    <code> append_to_buffer(char); </code>
                  </transition>
                </state>

                <history id="H" type="shallow"/>
              </state>
            </state>

            <history id="H" type="shallow"/>
          </state>
        </state>

        <!-- pinging orthogonal region -->
        <state id="Pinging" initial="Initial">
          <state id="Initial">
            <transition event="connected" target="../Pinging"/>
          </state>
          <state id="Pinging">
            <transition after="1 s" target="../ExpectingAnswer">
              <raise event="poll"/>
              <!-- <code> print("sent POLL"); </code> -->
            </transition>
          </state>
          <state id="ExpectingAnswer">
            <transition event="alive" target="../Pinging">
              <!-- <code> print("got ALIVE"); </code> -->
            </transition>
            <transition after="2 s" target="../Initial">
              <raise event="timeout"/>
              <code> print("polling timeout... disconnect"); </code>
            </transition>
          </state>
        </state>

        <!-- listening orthogonal region -->
        <state id="Receiving">
          <state id="Receiving">
            <transition event="receive_message(msg:str)" target=".">
              <code> add_message(msg, "remote_message"); </code>
            </transition>
          </state>
        </state>
      </parallel>
    </root>

  </statechart>
</single_instance_cd>