Fallible actions support

CHANGELOG.md

@@ -30,6 +30,9 @@ process.
 - `StateMachine::new` and `StateMachine::new_with_state` are now const functions
 - Fixed clippy warnings
 - [breaking] Changed guard functions return type from Result<(),_> to Result<bool,_>
+- [breaking] Changed action functions return type from () to Result<NextStateData,_>
+- [breaking] Disallow guards mutable access to the context
+- [breaking] Renamed GuardError to Error as it is now used for both guards and actions
 
 ## [v0.6.0] - 2022-11-02
 

examples/async.rs

@@ -22,39 +22,41 @@ pub struct Context {
 
 #[async_trait]
 impl StateMachineContext for Context {
-    fn guard3(&mut self) -> Result<bool, ()> {
+    fn guard3(&self) -> Result<bool, ()> {
         println!("`guard3` called from async context");
         Ok(true)
     }
 
-    async fn guard2(&mut self) -> Result<bool, ()> {
+    async fn guard2(&self) -> Result<bool, ()> {
         println!("`guard2` called from async context");
         let mut lock = self.lock.write().await;
         *lock = false;
         Ok(true)
     }
 
-    fn guard1(&mut self) -> Result<bool, ()> {
+    fn guard1(&self) -> Result<bool, ()> {
         println!("`guard1` called from sync context");
         Ok(true)
     }
 
-    async fn action2(&mut self) -> () {
+    async fn action2(&mut self) -> Result<(), ()> {
         println!("`action2` called from async context");
         if !*self.lock.read().await {
             self.done = true;
         }
+        Ok(())
     }
 
-    async fn action1(&mut self) -> () {
+    async fn action1(&mut self) -> Result<(), ()> {
         println!("`action1` called from async context");
         let mut lock = self.lock.write().await;
         *lock = true;
+        Ok(())
     }
 
-    fn action3(&mut self) -> bool {
+    fn action3(&mut self) -> Result<bool, ()> {
         println!("`action3` called from sync context, done = `{}`", self.done);
-        self.done
+        Ok(self.done)
     }
 }
 

examples/context.rs

@@ -20,12 +20,14 @@ pub struct Context {
 }
 
 impl StateMachineContext for Context {
-    fn count_transition1(&mut self) {
+    fn count_transition1(&mut self) -> Result<(), ()> {
         self.num_transitions += 1;
+        Ok(())
     }
 
-    fn count_transition2(&mut self) {
+    fn count_transition2(&mut self) -> Result<(), ()> {
         self.num_transitions += 1;
+        Ok(())
     }
 }
 

examples/dominos.rs

@@ -18,20 +18,20 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    fn to_d2(&mut self) -> Option<Events> {
-        Some(Events::ToD2)
+    fn to_d2(&mut self) -> Result<Option<Events>, ()> {
+        Ok(Some(Events::ToD2))
     }
 
-    fn to_d3(&mut self, _state_data: &Option<Events>) -> Option<Events> {
-        Some(Events::ToD3)
+    fn to_d3(&mut self, _state_data: &Option<Events>) -> Result<Option<Events>, ()> {
+        Ok(Some(Events::ToD3))
     }
 
-    fn to_d4(&mut self, _state_data: &Option<Events>) -> Option<Events> {
-        Some(Events::ToD4)
+    fn to_d4(&mut self, _state_data: &Option<Events>) -> Result<Option<Events>, ()> {
+        Ok(Some(Events::ToD4))
     }
 
-    fn to_d5(&mut self, _state_data: &Option<Events>) -> Option<Events> {
-        Some(Events::ToD5)
+    fn to_d5(&mut self, _state_data: &Option<Events>) -> Result<Option<Events>, ()> {
+        Ok(Some(Events::ToD5))
     }
 }
 

examples/event_with_data.rs

@@ -21,12 +21,13 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    fn guard(&mut self, event_data: &MyEventData) -> Result<bool, ()> {
+    fn guard(&self, event_data: &MyEventData) -> Result<bool, ()> {
         Ok(event_data == &MyEventData(42))
     }
 
-    fn action(&mut self, event_data: MyEventData) {
+    fn action(&mut self, event_data: MyEventData) -> Result<(), ()> {
         println!("Got valid Event Data = {}", event_data.0);
+        Ok(())
     }
 }
 

examples/event_with_mutable_data.rs

@@ -21,13 +21,14 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    fn guard(&mut self, event_data: &mut MyEventData) -> Result<bool, ()> {
+    fn guard(&self, event_data: &mut MyEventData) -> Result<bool, ()> {
         event_data.0 = 55;
         Ok(true)
     }
 
-    fn action(&mut self, event_data: &mut MyEventData) {
+    fn action(&mut self, event_data: &mut MyEventData) -> Result<(), ()> {
         println!("Got valid Event Data = {}", event_data.0);
+        Ok(())
     }
 }
 

examples/event_with_reference_data.rs

@@ -21,21 +21,23 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    fn guard1(&mut self, event_data: &[u8]) -> Result<bool, ()> {
+    fn guard1(&self, event_data: &[u8]) -> Result<bool, ()> {
         // Only ok if the slice is not empty
         Ok(!event_data.is_empty())
     }
 
-    fn action1(&mut self, event_data: &[u8]) {
+    fn action1(&mut self, event_data: &[u8]) -> Result<(), ()> {
         println!("Got valid Event Data = {:?}", event_data);
+        Ok(())
     }
 
-    fn guard2(&mut self, event_data: &MyReferenceWrapper) -> Result<bool, ()> {
+    fn guard2(&self, event_data: &MyReferenceWrapper) -> Result<bool, ()> {
         Ok(*event_data.0 > 9000)
     }
 
-    fn action2(&mut self, event_data: MyReferenceWrapper) {
+    fn action2(&mut self, event_data: MyReferenceWrapper) -> Result<(), ()> {
         println!("Got valid Event Data = {}", event_data.0);
+        Ok(())
     }
 }
 

examples/ex3.rs

@@ -18,22 +18,24 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    fn guard(&mut self) -> Result<bool, ()> {
+    fn guard(&self) -> Result<bool, ()> {
         // Always ok
         Ok(true)
     }
 
-    fn guard_fail(&mut self) -> Result<bool, ()> {
+    fn guard_fail(&self) -> Result<bool, ()> {
         // Always fail
         Ok(false)
     }
 
-    fn action1(&mut self) {
+    fn action1(&mut self) -> Result<(), ()> {
         //println!("Action 1");
+        Ok(())
     }
 
-    fn action2(&mut self) {
+    fn action2(&mut self) -> Result<(), ()> {
         //println!("Action 1");
+        Ok(())
     }
 }
 

examples/guard_action_syntax.rs

@@ -27,22 +27,22 @@ pub struct Context;
 
 impl StateMachineContext for Context {
     // Guard1 has access to the data from Event1
-    fn guard1(&mut self, _event_data: &MyEventData) -> Result<bool, ()> {
+    fn guard1(&self, _event_data: &MyEventData) -> Result<bool, ()> {
         todo!()
     }
 
     // Action1 has access to the data from Event1, and need to return the state data for State2
-    fn action1(&mut self, _event_data: MyEventData) -> MyStateData {
+    fn action1(&mut self, _event_data: MyEventData) -> Result<MyStateData, ()> {
         todo!()
     }
 
     // Guard2 has access to the data from State2
-    fn guard2(&mut self, _state_data: &MyStateData) -> Result<bool, ()> {
+    fn guard2(&self, _state_data: &MyStateData) -> Result<bool, ()> {
         todo!()
     }
 
     // Action2 has access to the data from State2
-    fn action2(&mut self, _state_data: &MyStateData) {
+    fn action2(&mut self, _state_data: &MyStateData) -> Result<(), ()> {
         todo!()
     }
 }

examples/guard_action_syntax_with_temporary_context.rs

@@ -28,29 +28,34 @@ pub struct Context;
 
 impl StateMachineContext for Context {
     // Guard1 has access to the data from Event1
-    fn guard1(&mut self, temp_context: &mut u16, _event_data: &MyEventData) -> Result<bool, ()> {
+    fn guard1(&self, temp_context: &mut u16, _event_data: &MyEventData) -> Result<bool, ()> {
         *temp_context += 1;
 
         Ok(true)
     }
 
     // Action1 has access to the data from Event1, and need to return the state data for State2
-    fn action1(&mut self, temp_context: &mut u16, _event_data: MyEventData) -> MyStateData {
+    fn action1(
+        &mut self,
+        temp_context: &mut u16,
+        _event_data: MyEventData,
+    ) -> Result<MyStateData, ()> {
         *temp_context += 1;
 
-        MyStateData(1)
+        Ok(MyStateData(1))
     }
 
     // Guard2 has access to the data from State2
-    fn guard2(&mut self, temp_context: &mut u16, _state_data: &MyStateData) -> Result<bool, ()> {
+    fn guard2(&self, temp_context: &mut u16, _state_data: &MyStateData) -> Result<bool, ()> {
         *temp_context += 1;
 
         Ok(true)
     }
 
     // Action2 has access to the data from State2
-    fn action2(&mut self, temp_context: &mut u16, _state_data: &MyStateData) {
+    fn action2(&mut self, temp_context: &mut u16, _state_data: &MyStateData) -> Result<(), ()> {
         *temp_context += 1;
+        Ok(())
     }
 }
 

examples/guard_custom_error.rs

@@ -34,23 +34,23 @@ statemachine! {
 pub struct Context;
 
 impl StateMachineContext for Context {
-    type GuardError = GuardError; // Guard1 has access to the data from Event1
-    fn guard1(&mut self, _event_data: &MyEventData) -> Result<bool, GuardError> {
+    type Error = GuardError; // Guard1 has access to the data from Event1
+    fn guard1(&self, _event_data: &MyEventData) -> Result<bool, GuardError> {
         Err(GuardError::Custom)
     }
 
     // Action1 has access to the data from Event1, and need to return the state data for State2
-    fn action1(&mut self, _event_data: MyEventData) -> MyStateData {
+    fn action1(&mut self, _event_data: MyEventData) -> Result<MyStateData, Self::Error> {
         todo!()
     }
 
     // Guard2 has access to the data from State2
-    fn guard2(&mut self, _state_data: &MyStateData) -> Result<bool, GuardError> {
+    fn guard2(&self, _state_data: &MyStateData) -> Result<bool, GuardError> {
         todo!()
     }
 
     // Action2 has access to the data from State2
-    fn action2(&mut self, _state_data: &MyStateData) {
+    fn action2(&mut self, _state_data: &MyStateData) -> Result<(), Self::Error> {
         todo!()
     }
 }

examples/named_async.rs

@@ -23,34 +23,36 @@ pub struct Context {
 
 #[async_trait]
 impl AsyncSimpleStateMachineContext for Context {
-    fn guard1(&mut self) -> Result<bool, ()> {
+    fn guard1(&self) -> Result<bool, ()> {
         println!("`guard1` called from sync context");
         Ok(true)
     }
 
-    async fn guard2(&mut self) -> Result<bool, ()> {
+    async fn guard2(&self) -> Result<bool, ()> {
         println!("`guard2` called from async context");
         let mut lock = self.lock.write().await;
         *lock = false;
         Ok(true)
     }
 
-    async fn action1(&mut self) -> () {
+    fn action3(&mut self) -> Result<bool, ()> {
+        println!("`action3` called from sync context, done = `{}`", self.done);
+        Ok(self.done)
+    }
+
+    async fn action1(&mut self) -> Result<(), ()> {
         println!("`action1` called from async context");
         let mut lock = self.lock.write().await;
         *lock = true;
+        Ok(())
     }
 
-    fn action3(&mut self) -> bool {
-        println!("`action3` called from sync context, done = `{}`", self.done);
-        self.done
-    }
-
-    async fn action2(&mut self) -> () {
+    async fn action2(&mut self) -> Result<(), ()> {
         println!("`action2` called from async context");
         if !*self.lock.read().await {
             self.done = true;
         }
+        Ok(())
     }
 }
 

examples/named_dominos.rs

@@ -19,20 +19,20 @@ statemachine! {
 pub struct Context;
 
 impl DominosStateMachineContext for Context {
-    fn to_d2(&mut self) -> Option<DominosEvents> {
-        Some(DominosEvents::ToD2)
+    fn to_d2(&mut self) -> Result<Option<DominosEvents>, ()> {
+        Ok(Some(DominosEvents::ToD2))
     }
 
-    fn to_d3(&mut self, _state_data: &Option<DominosEvents>) -> Option<DominosEvents> {
-        Some(DominosEvents::ToD3)
+    fn to_d3(&mut self, _state_data: &Option<DominosEvents>) -> Result<Option<DominosEvents>, ()> {
+        Ok(Some(DominosEvents::ToD3))
     }
 
-    fn to_d4(&mut self, _state_data: &Option<DominosEvents>) -> Option<DominosEvents> {
-        Some(DominosEvents::ToD4)
+    fn to_d4(&mut self, _state_data: &Option<DominosEvents>) -> Result<Option<DominosEvents>, ()> {
+        Ok(Some(DominosEvents::ToD4))
     }
 
-    fn to_d5(&mut self, _state_data: &Option<DominosEvents>) -> Option<DominosEvents> {
-        Some(DominosEvents::ToD5)
+    fn to_d5(&mut self, _state_data: &Option<DominosEvents>) -> Result<Option<DominosEvents>, ()> {
+        Ok(Some(DominosEvents::ToD5))
     }
 }
 

examples/named_ex3.rs

@@ -19,22 +19,24 @@ statemachine! {
 pub struct Context;
 
 impl LoopingWithGuardsStateMachineContext for Context {
-    fn guard(&mut self) -> Result<bool, ()> {
+    fn guard(&self) -> Result<bool, ()> {
         // Always ok
         Ok(true)
     }
 
-    fn guard_fail(&mut self) -> Result<bool, ()> {
+    fn guard_fail(&self) -> Result<bool, ()> {
         // Always fail
         Ok(false)
     }
 
-    fn action1(&mut self) {
+    fn action1(&mut self) -> Result<(), ()> {
         //println!("Action 1");
+        Ok(())
     }
 
-    fn action2(&mut self) {
+    fn action2(&mut self) -> Result<(), ()> {
         //println!("Action 1");
+        Ok(())
     }
 }