A nicer approach to manage dialogues via #[derive(Transition)] + #[teloxide(transition)]

CHANGELOG.md

@@ -7,8 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.3.0] - ???
 ### Added
  - `BotBuilder`, which allows setting a default `ParseMode`.
- - The `BotDialogue` trait.
- - Automatic `dispatch` function generation via `#[derive(BotDialogue)]` + `#[transition(transition_fn)]`.
+ - The `Transition`, `SubTransition`, `SubTransitionOutputType` traits.
+ - A nicer approach to manage dialogues via `#[derive(Transition)]` + `#[teloxide(transition)]`.
 
 ### Deprecated
  - `Bot::{from_env_with_client, new, with_client}`.

README.md

@@ -195,19 +195,12 @@ States and transition functions are placed into separated modules. For example,
 ```rust
 // Imports are omitted...
 
-#[derive(BotDialogue, SmartDefault, From)]
+#[derive(Transition, SmartDefault, From)]
 pub enum Dialogue {
     #[default]
-    #[transition(start)]
     Start(StartState),
-
-    #[transition(receive_days_of_week)]
     ReceiveDaysOfWeek(ReceiveDaysOfWeekState),
-
-    #[transition(receive_10x5_answer)]
     Receive10x5Answer(Receive10x5AnswerState),
-
-    #[transition(receive_gandalf_alternative_name)]
     ReceiveGandalfAlternativeName(ReceiveGandalfAlternativeNameState),
 }
 
@@ -228,16 +221,10 @@ pub struct ReceiveGandalfAlternativeNameState {
     _10x5_answer: u8,
 }
 
-pub struct ExitState {
-    rest: ReceiveGandalfAlternativeNameState,
-    gandalf_alternative_name: String,
-}
-
 up!(
     StartState -> ReceiveDaysOfWeekState,
     ReceiveDaysOfWeekState + [days_of_week: u8] -> Receive10x5AnswerState,
     Receive10x5AnswerState + [_10x5_answer: u8] -> ReceiveGandalfAlternativeNameState,
-    ReceiveGandalfAlternativeNameState + [gandalf_alternative_name: String] -> ExitState,
 );
 ```
 
@@ -249,15 +236,17 @@ The handy `up!` macro automatically generates functions that complete one state
 
 pub type Out = TransitionOut<Dialogue>;
 
-pub async fn start(cx: TransitionIn, state: StartState) -> Out {
+#[teloxide(transition)]
+async fn start(state: StartState, cx: TransitionIn) -> Out {
     cx.answer_str("Let's start our test! How many days per week are there?")
         .await?;
     next(state.up())
 }
 
-pub async fn receive_days_of_week(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_days_of_week(
     state: ReceiveDaysOfWeekState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text().map(str::parse) {
         Some(Ok(ans)) if ans == 7 => {
@@ -271,9 +260,10 @@ pub async fn receive_days_of_week(
     }
 }
 
-pub async fn receive_10x5_answer(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_10x5_answer(
     state: Receive10x5AnswerState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text().map(str::parse) {
         Some(Ok(ans)) if ans == 50 => {
@@ -287,9 +277,10 @@ pub async fn receive_10x5_answer(
     }
 }
 
-pub async fn receive_gandalf_alternative_name(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_gandalf_alternative_name(
     state: ReceiveGandalfAlternativeNameState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text() {
         Some(ans) if ans == "Mithrandir" => {
@@ -327,7 +318,7 @@ async fn main() {
                 input
                     .dialogue
                     .unwrap()
-                    .dispatch(input.cx)
+                    .react(input.cx)
                     .await
                     .expect("Something wrong with the bot!")
             },

examples/dialogue_bot/src/main.rs

@@ -1,17 +1,14 @@
-// This is a bot that asks your full name, your age, your favourite kind of
-// music and sends all the gathered information back.
+// This is a bot that asks you three questions, e.g. a simple test.
 //
 // # Example
 // ```
-//  - Let's start! First, what's your full name?
-//  - Luke Skywalker
-//  - What a wonderful name! Your age?
-//  - 26
-//  - Good. Now choose your favourite music
-// *A keyboard of music kinds is displayed*
-// *You select Metal*
-//  - Metal
-//  - Fine. Your full name: Luke Skywalker, your age: 26, your favourite music: Metal
+//  - Let's start our test! How many days per week are there?
+//  - 7
+//  - 10*5 = ?
+//  - 50
+//  - What's an alternative name of Gandalf?
+//  - Mithrandir
+//  - Congratulations! You've successfully passed the test!
 // ```
 
 #![allow(clippy::trivial_regex)]
@@ -21,8 +18,6 @@
 extern crate smart_default;
 #[macro_use]
 extern crate derive_more;
-#[macro_use]
-extern crate teloxide_macros;
 
 mod states;
 mod transitions;
@@ -50,7 +45,7 @@ async fn run() {
                 input
                     .dialogue
                     .unwrap()
-                    .dispatch(input.cx)
+                    .react(input.cx)
                     .await
                     .expect("Something wrong with the bot!")
             },

examples/dialogue_bot/src/states.rs

@@ -1,23 +1,12 @@
 use teloxide::prelude::*;
+use teloxide_macros::Transition;
 
-use super::transitions::{
-    receive_10x5_answer, receive_days_of_week,
-    receive_gandalf_alternative_name, start,
-};
-
-#[derive(BotDialogue, SmartDefault, From)]
+#[derive(Transition, SmartDefault, From)]
 pub enum Dialogue {
     #[default]
-    #[transition(start)]
     Start(StartState),
-
-    #[transition(receive_days_of_week)]
     ReceiveDaysOfWeek(ReceiveDaysOfWeekState),
-
-    #[transition(receive_10x5_answer)]
     Receive10x5Answer(Receive10x5AnswerState),
-
-    #[transition(receive_gandalf_alternative_name)]
     ReceiveGandalfAlternativeName(ReceiveGandalfAlternativeNameState),
 }
 
@@ -38,14 +27,8 @@ pub struct ReceiveGandalfAlternativeNameState {
     _10x5_answer: u8,
 }
 
-pub struct ExitState {
-    rest: ReceiveGandalfAlternativeNameState,
-    gandalf_alternative_name: String,
-}
-
 up!(
     StartState -> ReceiveDaysOfWeekState,
     ReceiveDaysOfWeekState + [days_of_week: u8] -> Receive10x5AnswerState,
     Receive10x5AnswerState + [_10x5_answer: u8] -> ReceiveGandalfAlternativeNameState,
-    ReceiveGandalfAlternativeNameState + [gandalf_alternative_name: String] -> ExitState,
 );

examples/dialogue_bot/src/transitions.rs

@@ -2,19 +2,23 @@ use crate::states::{
     Dialogue, Receive10x5AnswerState, ReceiveDaysOfWeekState,
     ReceiveGandalfAlternativeNameState, StartState,
 };
+
 use teloxide::prelude::*;
+use teloxide_macros::teloxide;
 
 pub type Out = TransitionOut<Dialogue>;
 
-pub async fn start(cx: TransitionIn, state: StartState) -> Out {
+#[teloxide(transition)]
+async fn start(state: StartState, cx: TransitionIn) -> Out {
     cx.answer_str("Let's start our test! How many days per week are there?")
         .await?;
     next(state.up())
 }
 
-pub async fn receive_days_of_week(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_days_of_week(
     state: ReceiveDaysOfWeekState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text().map(str::parse) {
         Some(Ok(ans)) if ans == 7 => {
@@ -28,9 +32,10 @@ pub async fn receive_days_of_week(
     }
 }
 
-pub async fn receive_10x5_answer(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_10x5_answer(
     state: Receive10x5AnswerState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text().map(str::parse) {
         Some(Ok(ans)) if ans == 50 => {
@@ -44,9 +49,10 @@ pub async fn receive_10x5_answer(
     }
 }
 
-pub async fn receive_gandalf_alternative_name(
-    cx: TransitionIn,
+#[teloxide(transition)]
+async fn receive_gandalf_alternative_name(
     state: ReceiveGandalfAlternativeNameState,
+    cx: TransitionIn,
 ) -> Out {
     match cx.update.text() {
         Some(ans) if ans == "Mithrandir" => {

examples/redis_remember_bot/src/main.rs

@@ -39,7 +39,7 @@ async fn run() {
                 let (cx, dialogue) = input.unpack();
 
                 dialogue
-                    .dispatch(cx)
+                    .react(cx)
                     .await
                     .expect("Something is wrong with the bot!")
             },

examples/redis_remember_bot/src/states.rs

@@ -1,7 +1,5 @@
 use teloxide::prelude::*;
-use teloxide_macros::BotDialogue;
-
-use super::transitions::{have_number, start};
+use teloxide_macros::Transition;
 
 use serde::{Deserialize, Serialize};
 
@@ -18,12 +16,9 @@ up!(
     StartState + [number: i32] -> HaveNumberState,
 );
 
-#[derive(BotDialogue, SmartDefault, From, Serialize, Deserialize)]
+#[derive(Transition, SmartDefault, From, Serialize, Deserialize)]
 pub enum Dialogue {
     #[default]
-    #[transition(start)]
     Start(StartState),
-
-    #[transition(have_number)]
     HaveNumber(HaveNumberState),
 }

examples/redis_remember_bot/src/transitions.rs

@@ -1,4 +1,5 @@
 use teloxide::prelude::*;
+use teloxide_macros::teloxide;
 
 use super::states::*;
 
@@ -17,7 +18,8 @@ macro_rules! extract_text {
 
 pub type Out = TransitionOut<Dialogue>;
 
-pub async fn start(cx: TransitionIn, state: StartState) -> Out {
+#[teloxide(transition)]
+async fn start(state: StartState, cx: TransitionIn) -> Out {
     let text = extract_text!(cx);
 
     if let Ok(number) = text.parse() {
@@ -33,7 +35,8 @@ pub async fn start(cx: TransitionIn, state: StartState) -> Out {
     }
 }
 
-pub async fn have_number(cx: TransitionIn, state: HaveNumberState) -> Out {
+#[teloxide(transition)]
+async fn have_number(state: HaveNumberState, cx: TransitionIn) -> Out {
     let text = extract_text!(cx);
     let num = state.number;
 

src/dispatching/dialogue/bot_dialogue.rs

@@ -1,11 +0,0 @@
-use crate::dispatching::dialogue::{TransitionIn, TransitionOut};
-use futures::future::BoxFuture;
-
-/// Represents a dialogue FSM.
-pub trait BotDialogue: Default {
-    /// Turns itself into another state, depending on the input message.
-    fn dispatch(
-        self,
-        cx: TransitionIn,
-    ) -> BoxFuture<'static, TransitionOut<Self>>;
-}

src/dispatching/dialogue/mod.rs

@@ -2,9 +2,11 @@
 //!
 //! There are three main components:
 //!
-//!  1. Your type `D` (typically an enumeration), implementing [`BotDialogue`].
+//!  1. Your type `D` (typically an enumeration), implementing [`Transition`].
 //! It is essentially a [FSM]: its variants are possible dialogue states and
-//! [`BotDialogue::dispatch`] is a transition function.
+//! [`Transition::react`] is a transition function.
+//!
+//!  2. State types, forming `D`. They implement [`SubTransition`].
 //!
 //!  2. [`Storage<D>`], which encapsulates all the dialogues.
 //!
@@ -30,7 +32,7 @@
 //! use std::convert::Infallible;
 //!
 //! use teloxide::prelude::*;
-//! use teloxide_macros::BotDialogue;
+//! use teloxide_macros::{teloxide, Transition};
 //!
 //! struct _1State;
 //! struct _2State;
@@ -38,23 +40,25 @@
 //!
 //! type Out = TransitionOut<D>;
 //!
-//! async fn _1_transition(_cx: TransitionIn, _state: _1State) -> Out {
-//!     todo!()
-//! }
-//! async fn _2_transition(_cx: TransitionIn, _state: _2State) -> Out {
-//!     todo!()
-//! }
-//! async fn _3_transition(_cx: TransitionIn, _state: _3State) -> Out {
+//! #[teloxide(transition)]
+//! async fn _1_transition(_state: _1State, _cx: TransitionIn) -> Out {
 //!     todo!()
 //! }
 //!
-//! #[derive(BotDialogue)]
+//! #[teloxide(transition)]
+//! async fn _2_transition(_state: _2State, _cx: TransitionIn) -> Out {
+//!     todo!()
+//! }
+//!
+//! #[teloxide(transition)]
+//! async fn _3_transition(_state: _3State, _cx: TransitionIn) -> Out {
+//!     todo!()
+//! }
+//!
+//! #[derive(Transition)]
 //! enum D {
-//!     #[transition(_1_transition)]
 //!     _1(_1State),
-//!     #[transition(_2_transition)]
 //!     _2(_2State),
-//!     #[transition(_3_transition)]
 //!     _3(_3State),
 //! }
 //!
@@ -94,9 +98,10 @@
 //!
 //! See [examples/dialogue_bot] as a real example.
 //!
-//! [`BotDialogue`]: crate::dispatching::dialogue::BotDialogue
-//! [`BotDialogue::dispatch`]:
-//! crate::dispatching::dialogue::BotDialogue::dispatch
+//! [`Transition`]: crate::dispatching::dialogue::Transition
+//! [`SubTransition`]: crate::dispatching::dialogue::SubTransition
+//! [`Transition::react`]:
+//! crate::dispatching::dialogue::Transition::react
 //! [FSM]: https://en.wikipedia.org/wiki/Finite-state_machine
 //!
 //! [`Storage<D>`]: crate::dispatching::dialogue::Storage
@@ -122,26 +127,27 @@
 
 #![allow(clippy::type_complexity)]
 
-mod bot_dialogue;
 mod dialogue_dispatcher;
 mod dialogue_dispatcher_handler;
 mod dialogue_stage;
 mod dialogue_with_cx;
 mod get_chat_id;
 mod storage;
+mod transition;
 
-use crate::{requests::ResponseResult, types::Message};
-pub use bot_dialogue::BotDialogue;
 pub use dialogue_dispatcher::DialogueDispatcher;
 pub use dialogue_dispatcher_handler::DialogueDispatcherHandler;
 pub use dialogue_stage::{exit, next, DialogueStage};
 pub use dialogue_with_cx::DialogueWithCx;
 pub use get_chat_id::GetChatId;
+pub use transition::{
+    SubTransition, SubTransitionOutputType, Transition, TransitionIn,
+    TransitionOut,
+};
 
 #[cfg(feature = "redis-storage")]
 pub use storage::{RedisStorage, RedisStorageError};
 
-use crate::dispatching::UpdateWithCx;
 pub use storage::{serializer, InMemStorage, Serializer, Storage};
 
 /// Generates `.up(field)` methods for dialogue states.
@@ -192,9 +198,3 @@ macro_rules! up {
         )+
     };
 }
-
-/// An input passed into a FSM transition function.
-pub type TransitionIn = UpdateWithCx<Message>;
-
-/// A type returned from a FSM transition function.
-pub type TransitionOut<D> = ResponseResult<DialogueStage<D>>;

src/dispatching/dialogue/transition.rs

@@ -0,0 +1,44 @@
+use crate::{
+    dispatching::{dialogue::DialogueStage, UpdateWithCx},
+    requests::ResponseResult,
+    types::Message,
+};
+use futures::future::BoxFuture;
+
+/// Represents a transition function of a dialogue FSM.
+pub trait Transition: Sized {
+    /// Turns itself into another state, depending on the input message.
+    fn react(self, cx: TransitionIn)
+        -> BoxFuture<'static, TransitionOut<Self>>;
+}
+
+/// Like [`Transition`], but from `StateN` -> `Dialogue`.
+///
+/// [`Transition`]: crate::dispatching::dialogue::Transition
+pub trait SubTransition<Dialogue>
+where
+    Dialogue: Transition,
+{
+    /// Turns itself into another state, depending on the input message.
+    fn react(
+        self,
+        cx: TransitionIn,
+    ) -> BoxFuture<'static, TransitionOut<Dialogue>>;
+}
+
+/// A type returned from a FSM subtransition function.
+///
+/// Now it is used only inside `#[teloxide(transition)]` for type inference.
+pub trait SubTransitionOutputType {
+    type Output;
+}
+
+impl<D> SubTransitionOutputType for TransitionOut<D> {
+    type Output = D;
+}
+
+/// An input passed into a FSM (sub)transition function.
+pub type TransitionIn = UpdateWithCx<Message>;
+
+/// A type returned from a FSM (sub)transition function.
+pub type TransitionOut<D> = ResponseResult<DialogueStage<D>>;

src/prelude.rs

@@ -3,8 +3,8 @@
 pub use crate::{
     dispatching::{
         dialogue::{
-            exit, next, BotDialogue, DialogueDispatcher, DialogueStage,
-            DialogueWithCx, GetChatId, TransitionIn, TransitionOut,
+            exit, next, DialogueDispatcher, DialogueStage, DialogueWithCx,
+            GetChatId, Transition, TransitionIn, TransitionOut,
         },
         Dispatcher, DispatcherHandlerRx, DispatcherHandlerRxExt, UpdateWithCx,
     },