Use macros to make the state machine easier to read

CMakeLists.txt

@@ -4,5 +4,3 @@ set (CMAKE_CXX_STANDARD 11)
 project(state_machine)
 
 add_executable(usm_test test/usm_test.cpp)
-
-#install(TARGETS state_machine RUNTIME DESTINATION bin)

include/usm.hpp

@@ -1,71 +1,99 @@
 #pragma once
 
 /*
- * Copyright (c) 2019 Julian Kent. All rights reserved.
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * * Redistributions of source code must retain the above copyright notice, this
- *   list of conditions and the following disclaimer.
- *
- * * Redistributions in binary form must reproduce the above copyright notice,
- *   this list of conditions and the following disclaimer in the documentation
- *   and/or other materials provided with the distribution.
- *
- * * Neither the name of libgnc nor the names of its
- *   contributors may be used to endorse or promote products derived from
- *   this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- *
- *
- * For usage examples, look at the tests.
+* Copyright (c) 2019 Julian Kent. All rights reserved.
+*
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*
+* * Redistributions of source code must retain the above copyright notice, this
+*   list of conditions and the following disclaimer.
+*
+* * Redistributions in binary form must reproduce the above copyright notice,
+*   this list of conditions and the following disclaimer in the documentation
+*   and/or other materials provided with the distribution.
+*
+* * Neither the name of libgnc nor the names of its
+*   contributors may be used to endorse or promote products derived from
+*   this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*
+*
+* For usage examples, look at the tests.
 */
 
 namespace usm {
 
-enum Transition { REPEAT, NEXT, NEXT2, NEXT3, NEXT4, ERROR };
+enum Transition { REPEAT, NEXT1, NEXT2, NEXT3, NEXT4, ERROR };
 
-template <typename StateEnum> class StateMachine {
-public:
-    StateMachine(StateEnum startingState);
-    void iterateOnce();
+template <typename StateEnum>
+class StateMachine {
+ public:
+  StateMachine(StateEnum startingState);
+  void iterateOnce();
 
-    StateEnum getState();
+  StateEnum getState();
 
-protected:
-    virtual Transition runCurrentState(StateEnum currentState) = 0; // a big switch
-    virtual StateEnum chooseNextState(StateEnum currentState, Transition transition) = 0; // nested switches
+ protected:
+  virtual Transition runCurrentState(
+      StateEnum currentState) = 0;  // a big switch
+  virtual StateEnum chooseNextState(
+      StateEnum currentState, Transition transition) = 0;  // nested switches
 
-private:
-    StateEnum m_currentState;
+ private:
+  StateEnum m_currentState;
 };
 
 /*---------------IMPLEMENTATION------------------*/
 
 template <typename StateEnum>
 StateMachine<StateEnum>::StateMachine(StateEnum startingState)
-    : m_currentState(startingState)
-{
-}
+    : m_currentState(startingState) {}
 
-template <typename StateEnum> void StateMachine<StateEnum>::iterateOnce()
-{
-    m_currentState = chooseNextState(m_currentState, runCurrentState(m_currentState));
+template <typename StateEnum>
+void StateMachine<StateEnum>::iterateOnce() {
+  Transition t = runCurrentState(m_currentState);
+  if (t != REPEAT) m_currentState = chooseNextState(m_currentState, t);
 }
 
-template <typename StateEnum> StateEnum StateMachine<StateEnum>::getState() { return m_currentState; }
+template <typename StateEnum>
+StateEnum StateMachine<StateEnum>::getState() {
+  return m_currentState;
+}
 }
+
+/*---------------MACROS TO MAKE TRANSITION TABLES EASY------------------*/
+
+// clang-format off
+#define USM_TABLE(current_state, error, ...) \
+switch (current_state) { \
+    __VA_ARGS__; \
+    default: break; \
+} \
+return error
+
+#define USM_STATE(transition, start_state, ...) \
+    case start_state: \
+        switch (transition) { \
+            __VA_ARGS__; \
+            default: break; \
+        } \
+    break
+
+#define USM_MAP(transition, next_state) \
+            case transition: return next_state
+
+// clang-format on