Add dialogue::{next, exit}

examples/simple_dialogue/Cargo.toml

@@ -11,6 +11,7 @@ pretty_env_logger = "0.3.1"
 log = "0.4.8"
 tokio = "0.2.9"
 strum = "0.17.1"
+smart-default = "0.6.0"
 strum_macros = "0.17.1"
 teloxide = { path = "../../" }
 

examples/simple_dialogue/src/main.rs

@@ -1,5 +1,7 @@
 #[macro_use]
 extern crate strum_macros;
+#[macro_use]
+extern crate smart_default;
 
 use std::fmt::{self, Display, Formatter};
 use teloxide::{
@@ -57,19 +59,15 @@ impl Display for User {
 // [States of a dialogue]
 // ============================================================================
 
+#[derive(SmartDefault)]
 enum State {
+    #[default]
     Start,
     FullName,
     Age,
     FavouriteMusic,
 }
 
-impl Default for State {
-    fn default() -> Self {
-        Self::Start
-    }
-}
-
 // ============================================================================
 // [Control a dialogue]
 // ============================================================================
@@ -90,14 +88,14 @@ async fn start(mut ctx: Ctx) -> Res {
     ctx.reply("Let's start! First, what's your full name?")
         .await?;
     ctx.dialogue.state = State::FullName;
-    Ok(DialogueStage::Next(ctx.dialogue))
+    next(ctx.dialogue)
 }
 
 async fn full_name(mut ctx: Ctx) -> Res {
     ctx.reply("What a wonderful name! Your age?").await?;
     ctx.dialogue.data.full_name = Some(ctx.update.text().unwrap().to_owned());
     ctx.dialogue.state = State::Age;
-    Ok(DialogueStage::Next(ctx.dialogue))
+    next(ctx.dialogue)
 }
 
 async fn age(mut ctx: Ctx) -> Res {
@@ -110,7 +108,7 @@ async fn age(mut ctx: Ctx) -> Res {
         Err(_) => ctx.reply("Oh, please, enter a number!").await?,
     }
 
-    Ok(DialogueStage::Next(ctx.dialogue))
+    next(ctx.dialogue)
 }
 
 async fn favourite_music(mut ctx: Ctx) -> Res {
@@ -118,11 +116,11 @@ async fn favourite_music(mut ctx: Ctx) -> Res {
         Ok(ok) => {
             ctx.dialogue.data.favourite_music = Some(ok);
             ctx.reply(format!("Fine. {}", ctx.dialogue.data)).await?;
-            Ok(DialogueStage::Exit)
+            exit()
         }
         Err(_) => {
             ctx.reply("Oh, please, enter from the keyboard!").await?;
-            Ok(DialogueStage::Next(ctx.dialogue))
+            next(ctx.dialogue)
         }
     }
 }
@@ -147,7 +145,7 @@ async fn main() {
     log::info!("Starting the simple_dialogue bot!");
 
     Dispatcher::new(Bot::new("YourAwesomeToken"))
-        .message_handler(DialogueDispatcher::new(|ctx| async move {
+        .message_handler(&DialogueDispatcher::new(|ctx| async move {
             handle_message(ctx)
                 .await
                 .expect("Something wrong with the bot!")

src/dispatching/dialogue/dialogue_stage.rs

@@ -0,0 +1,20 @@
+use crate::dispatching::dialogue::Dialogue;
+
+/// Continue or terminate a dialogue.
+#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq)]
+pub enum DialogueStage<State, T> {
+    Next(Dialogue<State, T>),
+    Exit,
+}
+
+/// A shortcut for `Ok(DialogueStage::Next(dialogue))`.
+pub fn next<E, State, T>(
+    dialogue: Dialogue<State, T>,
+) -> Result<DialogueStage<State, T>, E> {
+    Ok(DialogueStage::Next(dialogue))
+}
+
+/// A shortcut for `Ok(DialogueStage::Exit)`.
+pub fn exit<E, State, T>() -> Result<DialogueStage<State, T>, E> {
+    Ok(DialogueStage::Exit)
+}

src/dispatching/dialogue/dialogue_state.rs

@@ -1,8 +0,0 @@
-use crate::dispatching::dialogue::Dialogue;
-
-/// Continue or terminate a dialogue.
-#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq)]
-pub enum DialogueStage<State, T> {
-    Next(Dialogue<State, T>),
-    Exit,
-}

src/dispatching/dialogue/mod.rs

@@ -37,13 +37,13 @@
 mod dialogue;
 mod dialogue_dispatcher;
 mod dialogue_handler_ctx;
-mod dialogue_state;
+mod dialogue_stage;
 mod get_chat_id;
 mod storage;
 
 pub use dialogue::Dialogue;
 pub use dialogue_dispatcher::DialogueDispatcher;
 pub use dialogue_handler_ctx::DialogueHandlerCtx;
-pub use dialogue_state::DialogueStage;
+pub use dialogue_stage::{exit, next, DialogueStage};
 pub use get_chat_id::GetChatId;
 pub use storage::{InMemStorage, Storage};

src/dispatching/dispatcher.rs

@@ -8,7 +8,7 @@ use crate::{
         CallbackQuery, ChosenInlineResult, InlineQuery, Message, Poll,
         PollAnswer, PreCheckoutQuery, ShippingQuery, Update, UpdateKind,
     },
-    Bot,
+    Bot, RequestError,
 };
 use futures::{stream, StreamExt};
 use std::{fmt::Debug, future::Future, sync::Arc};
@@ -26,7 +26,9 @@ type Handlers<'a, Upd, HandlerE> = Vec<
 ///
 /// See [the module-level documentation for the design
 /// overview](crate::dispatching).
-pub struct Dispatcher<'a, HandlerE> {
+// HandlerE=RequestError doesn't work now, because of very poor type inference.
+// See https://github.com/rust-lang/rust/issues/27336 for more details.
+pub struct Dispatcher<'a, HandlerE = RequestError> {
     bot: Arc<Bot>,
 
     handlers_error_handler: Box<dyn ErrorHandler<HandlerE> + 'a>,

src/dispatching/mod.rs

@@ -25,7 +25,7 @@
 //!
 //! // Setup logging here...
 //!
-//! Dispatcher::new(Bot::new("MyAwesomeToken"))
+//! Dispatcher::<RequestError>::new(Bot::new("MyAwesomeToken"))
 //!     .message_handler(&|ctx: DispatcherHandlerCtx<Message>| async move {
 //!         ctx.answer("pong").send().await?;
 //!         Ok(())

src/prelude.rs

@@ -3,7 +3,8 @@
 pub use crate::{
     dispatching::{
         dialogue::{
-            DialogueDispatcher, DialogueHandlerCtx, DialogueStage, GetChatId,
+            exit, next, DialogueDispatcher, DialogueHandlerCtx, DialogueStage,
+            GetChatId,
         },
         Dispatcher, DispatcherHandlerCtx,
     },