Merge pull request #1 from yuk1ty/feature/add-state-machine-trait

Add `StateMachineBuilder` trait
yuk1ty · Feb 3, 2021 · 28d4f31 · 28d4f31
2 parents 51752e0 + 30df05c
commit 28d4f31
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Showing 3 changed files with 67 additions and 33 deletions.
diff --git a/src/lib.rs b/src/lib.rs
@@ -9,9 +9,11 @@
 //! from given string ("next") and then, it produces outputs.
 //!
 //! ```rust
-//! use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+//! use statemachine_rs::machine::{
+//!     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+//! };
 //!
-//! let sm = StateMachineBuilder::start()
+//! let sm = BasicStateMachineBuilder::start()
 //!     .initial_state(1)
 //!     .transition(|state, input| match (state, input) {
 //!         (1, "next") => 2,
@@ -35,7 +37,9 @@
 //! The following example describes if you press the button, the state turns to be `On`. Otherwise, `Off`.
 //!
 //! ```rust
-//! use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+//! use statemachine_rs::machine::{
+//!     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+//! };
 //!
 //! #[derive(Clone, Debug, PartialEq)]
 //! enum ButtonState {
@@ -47,7 +51,7 @@
 //!     Press,
 //! }
 //!
-//! let sm = StateMachineBuilder::start()
+//! let sm = BasicStateMachineBuilder::start()
 //!     .initial_state(ButtonState::Off)
 //!     .transition(|state, input| match (state, input) {
 //!         (ButtonState::On, Input::Press) => ButtonState::Off,

diff --git a/src/machine/builder.rs b/src/machine/builder.rs
@@ -1,10 +1,33 @@
 use std::{cell::RefCell, marker::PhantomData};
 
-use super::{error::StateMachineError, BasicStateMachine, StateMachine, StateWrapper};
+use super::{error::StateMachineError, BasicStateMachine, StateWrapper};
+
+pub trait StateMachineBuilder<State, Input, Transition>
+where
+    Transition: Fn(&State, Input) -> State,
+    State: Clone,
+{
+    type Output;
+
+    /// Starts the builder.
+    fn start() -> Self;
+
+    /// Sets particular initial state to the state machine.
+    fn initial_state(self, state: State) -> Self;
+
+    /// Sets particular state to the current state.
+    fn current_state(self, state: State) -> Self;
+
+    /// Sets particular transition algorithm to the state machine.
+    fn transition(self, next: Transition) -> Self;
+
+    /// To finish the builder. If it fails, returns [`crate::machine::error::StateMachineError`].
+    fn build(self) -> Result<Self::Output, Box<dyn std::error::Error>>;
+}
 
 /// This builder enables us to assemble StateMachine
 /// (like [`crate::machine::BasicStateMachine`]) more easily.
-pub struct StateMachineBuilder<State, Input, Transition>
+pub struct BasicStateMachineBuilder<State, Input, Transition>
 where
     Transition: Fn(&State, Input) -> State,
     State: Clone,
@@ -16,35 +39,33 @@ where
 }
 
 impl<State, Input, Transition> StateMachineBuilder<State, Input, Transition>
+    for BasicStateMachineBuilder<State, Input, Transition>
 where
     Transition: Fn(&State, Input) -> State,
     State: Clone,
 {
-    /// Starts the builder.
-    pub fn start() -> Self {
+    type Output = BasicStateMachine<State, Input, Transition>;
+
+    fn start() -> Self {
         Self::default()
     }
 
-    /// Sets particular initial state to the state machine.
-    pub fn initial_state(mut self, state: State) -> Self {
+    fn initial_state(mut self, state: State) -> Self {
         self.initial_state = Some(state);
         self
     }
 
-    /// Sets particular state to the current state.
-    pub fn current_state(mut self, state: State) -> Self {
+    fn current_state(mut self, state: State) -> Self {
         self.current_state = Some(state);
         self
     }
 
-    /// Sets particular transition algorithm to the state machine.
-    pub fn transition(mut self, next: Transition) -> Self {
+    fn transition(mut self, next: Transition) -> Self {
         self.transition = Some(next);
         self
     }
 
-    /// To finish the builder. If it fails, returns [`crate::machine::error::StateMachineError`].
-    pub fn build(self) -> Result<impl StateMachine<State, Input>, Box<dyn std::error::Error>> {
+    fn build(self) -> Result<Self::Output, Box<dyn std::error::Error>> {
         match (self.initial_state, self.transition) {
             (Some(initial_state), Some(transition)) => Ok(BasicStateMachine {
                 initial_state: initial_state.clone(),
@@ -70,13 +91,13 @@ where
     }
 }
 
-impl<State, Input, Transition> Default for StateMachineBuilder<State, Input, Transition>
+impl<State, Input, Transition> Default for BasicStateMachineBuilder<State, Input, Transition>
 where
     Transition: Fn(&State, Input) -> State,
     State: Clone,
 {
     fn default() -> Self {
-        StateMachineBuilder {
+        BasicStateMachineBuilder {
             initial_state: None,
             current_state: None,
             transition: None,
@@ -87,10 +108,9 @@ where
 
 #[cfg(test)]
 mod test {
+    use super::{BasicStateMachineBuilder, StateMachineBuilder};
     use crate::machine::StateMachine;
 
-    use super::StateMachineBuilder;
-
     #[allow(dead_code)]
     #[derive(Copy, Clone, Debug, PartialEq)]
     enum Stations {
@@ -112,7 +132,7 @@ mod test {
     #[test]
     fn test_build() {
         // sets only initial state
-        let sm = StateMachineBuilder::start()
+        let sm = BasicStateMachineBuilder::start()
             .initial_state(Stations::Shibuya)
             .transition(|station, train| match (station, train) {
                 (Stations::Shibuya, Train::Local) => Stations::IkejiriOhashi,
@@ -130,7 +150,7 @@ mod test {
         assert_eq!(Stations::Shibuya, sm.current_state());
 
         // sets current state after initializing initial state
-        let sm = StateMachineBuilder::start()
+        let sm = BasicStateMachineBuilder::start()
             .initial_state(Stations::Shibuya)
             .current_state(Stations::Sangendyaya)
             .transition(|station, train| match (station, train) {
@@ -151,7 +171,7 @@ mod test {
 
     #[test]
     fn test_fail_initial_state() {
-        let sm = StateMachineBuilder::start()
+        let sm = BasicStateMachineBuilder::start()
             .transition(|station, train| match (station, train) {
                 (Stations::Shibuya, Train::Local) => Stations::IkejiriOhashi,
                 (Stations::Shibuya, Train::Express) => Stations::Sangendyaya,

diff --git a/src/machine/mod.rs b/src/machine/mod.rs
@@ -13,7 +13,9 @@ pub trait StateMachine<State, Input> {
     ///
     /// # Example
     /// ```
-    /// use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+    /// use statemachine_rs::machine::{
+    ///     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+    /// };
     ///
     /// #[derive(Clone, Debug, PartialEq)]
     /// enum ButtonState {
@@ -26,7 +28,7 @@ pub trait StateMachine<State, Input> {
     ///     Press,
     /// }
     ///
-    /// let sm = StateMachineBuilder::start()
+    /// let sm = BasicStateMachineBuilder::start()
     ///     .initial_state(ButtonState::Off)
     ///     .transition(|state, input| match (state, input) {
     ///         (ButtonState::On, Input::Press) => ButtonState::Off,
@@ -43,7 +45,9 @@ pub trait StateMachine<State, Input> {
     ///
     /// # Example
     /// ```
-    /// use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+    /// use statemachine_rs::machine::{
+    ///     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+    /// };
     ///
     /// #[derive(Clone, Debug, PartialEq)]
     /// enum ButtonState {
@@ -55,7 +59,7 @@ pub trait StateMachine<State, Input> {
     ///     Press,
     /// }
     ///
-    /// let sm = StateMachineBuilder::start()
+    /// let sm = BasicStateMachineBuilder::start()
     ///     .initial_state(ButtonState::Off)
     ///     .transition(|state, input| match (state, input) {
     ///         (ButtonState::On, Input::Press) => ButtonState::Off,
@@ -73,7 +77,9 @@ pub trait StateMachine<State, Input> {
     ///
     /// # Example
     /// ```
-    /// use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+    /// use statemachine_rs::machine::{
+    ///     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+    /// };
     ///
     /// #[derive(Clone, Debug, PartialEq)]
     /// enum ButtonState {
@@ -85,7 +91,7 @@ pub trait StateMachine<State, Input> {
     ///     Press,
     /// }
     ///
-    /// let sm = StateMachineBuilder::start()
+    /// let sm = BasicStateMachineBuilder::start()
     ///     .initial_state(ButtonState::Off)
     ///     .transition(|state, input| match (state, input) {
     ///         (ButtonState::On, Input::Press) => ButtonState::Off,
@@ -103,7 +109,9 @@ pub trait StateMachine<State, Input> {
     ///
     /// # Example
     /// ```
-    /// use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+    /// use statemachine_rs::machine::{
+    ///     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+    /// };
     ///
     /// #[derive(Clone, Debug, PartialEq)]
     /// enum ButtonState {
@@ -115,7 +123,7 @@ pub trait StateMachine<State, Input> {
     ///     Press,
     /// }
     ///
-    /// let sm = StateMachineBuilder::start()
+    /// let sm = BasicStateMachineBuilder::start()
     ///     .initial_state(ButtonState::Off)
     ///     .transition(|state, input| match (state, input) {
     ///         (ButtonState::On, Input::Press) => ButtonState::Off,
@@ -133,7 +141,9 @@ pub trait StateMachine<State, Input> {
     ///
     /// # Example
     /// ```
-    /// use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
+    /// use statemachine_rs::machine::{
+    ///     builder::BasicStateMachineBuilder, builder::StateMachineBuilder, StateMachine,
+    /// };
     ///
     /// #[derive(Clone, Debug, PartialEq)]
     /// enum ButtonState {
@@ -146,7 +156,7 @@ pub trait StateMachine<State, Input> {
     ///     Press,
     /// }
     ///
-    /// let sm = StateMachineBuilder::start()
+    /// let sm = BasicStateMachineBuilder::start()
     ///     .initial_state(ButtonState::Off)
     ///     .transition(|state, input| match (state, input) {
     ///         (ButtonState::On, Input::Press) => ButtonState::Off,