Merge pull request #669 from teloxide/use-default-enum-variant

Use `#[default]` for `State::Start` in dialogues

Former-commit-id: 9290665d04

examples/db_remember.rs

@@ -14,18 +14,13 @@ type MyDialogue = Dialogue<State, ErasedStorage<State>>;
 type MyStorage = std::sync::Arc<ErasedStorage<State>>;
 type HandlerResult = Result<(), Box<dyn std::error::Error + Send + Sync>>;
 
-#[derive(Clone, serde::Serialize, serde::Deserialize)]
+#[derive(Clone, Default, serde::Serialize, serde::Deserialize)]
 pub enum State {
+    #[default]
     Start,
     GotNumber(i32),
 }
 
-impl Default for State {
-    fn default() -> Self {
-        Self::Start
-    }
-}
-
 #[derive(Clone, BotCommands)]
 #[command(rename = "lowercase", description = "These commands are supported:")]
 pub enum Command {

examples/dialogue.rs

@@ -18,18 +18,18 @@ use teloxide::{dispatching::dialogue::InMemStorage, prelude::*};
 type MyDialogue = Dialogue<State, InMemStorage<State>>;
 type HandlerResult = Result<(), Box<dyn std::error::Error + Send + Sync>>;
 
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub enum State {
+    #[default]
     Start,
     ReceiveFullName,
-    ReceiveAge { full_name: String },
-    ReceiveLocation { full_name: String, age: u8 },
-}
-
-impl Default for State {
-    fn default() -> Self {
-        Self::Start
-    }
+    ReceiveAge {
+        full_name: String,
+    },
+    ReceiveLocation {
+        full_name: String,
+        age: u8,
+    },
 }
 
 #[tokio::main]

examples/purchase.rs

@@ -25,17 +25,14 @@ use teloxide::{
 type MyDialogue = Dialogue<State, InMemStorage<State>>;
 type HandlerResult = Result<(), Box<dyn std::error::Error + Send + Sync>>;
 
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub enum State {
+    #[default]
     Start,
     ReceiveFullName,
-    ReceiveProductChoice { full_name: String },
-}
-
-impl Default for State {
-    fn default() -> Self {
-        Self::Start
-    }
+    ReceiveProductChoice {
+        full_name: String,
+    },
 }
 
 #[derive(BotCommands, Clone)]

src/dispatching/dialogue.rs

@@ -13,8 +13,9 @@
 //! dialogues. Your dialogue state can be represented as an enumeration:
 //!
 //! ```ignore
-//! #[derive(Clone)]
+//! #[derive(Clone, Default)]
 //! pub enum State {
+//!     #[default]
 //!     Start,
 //!     ReceiveFullName,
 //!     ReceiveAge { full_name: String },