ch18 パターンとマッチングの和訳を最新版に更新

rust-lang/book@19c40bf

Author: shinmili

listings/ch18-patterns-and-matching/listing-18-01/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-01/src/main.rs

@@ -4,16 +4,21 @@ fn main() {
     let age: Result<u8, _> = "34".parse();
 
     if let Some(color) = favorite_color {
-        println!("Using your favorite color, {}, as the background", color);
+        //       "あなたのお気に入りの色、{color}を背景色に使用します"
+        println!("Using your favorite color, {color}, as the background");
     } else if is_tuesday {
+        //       "火曜日は緑の日！"
         println!("Tuesday is green day!");
     } else if let Ok(age) = age {
         if age > 30 {
+            //       "紫を背景色に使用します"
             println!("Using purple as the background color");
         } else {
+            //       "オレンジを背景色に使用します"
             println!("Using orange as the background color");
         }
     } else {
+        //       "青を背景色に使用します"
         println!("Using blue as the background color");
     }
 }

listings/ch18-patterns-and-matching/listing-18-02/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-03/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-04/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-05/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-05/output.txt

@@ -4,14 +4,14 @@ error[E0308]: mismatched types
  --> src/main.rs:2:9
   |
 2 |     let (x, y) = (1, 2, 3);
-  |         ^^^^^^ expected a tuple with 3 elements, found one with 2 elements
+  |         ^^^^^^   --------- this expression has type `({integer}, {integer}, {integer})`
+  |         |                 (この式は型`({integer}, {integer}, {integer})`を持ちます)
+  |         |
+  |         expected a tuple with 3 elements, found one with 2 elements
+  |        (3要素のタプルを予期したのに、2要素のタプルが見つかりました)
   |
   = note: expected tuple `({integer}, {integer}, {integer})`
              found tuple `(_, _)`
 
-error: aborting due to previous error
-
 For more information about this error, try `rustc --explain E0308`.
-error: could not compile `patterns`.
-
-To learn more, run the command again with --verbose.
+error: could not compile `patterns` (bin "patterns") due to 1 previous error

listings/ch18-patterns-and-matching/listing-18-06/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-07/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-07/src/main.rs

@@ -1,4 +1,5 @@
 fn print_coordinates(&(x, y): &(i32, i32)) {
+    //       "現在の位置: ({}, {})"
     println!("Current location: ({}, {})", x, y);
 }
 

listings/ch18-patterns-and-matching/listing-18-08/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-08/output.txt

@@ -1,21 +1,24 @@
 $ cargo run
    Compiling patterns v0.1.0 (file:///projects/patterns)
-error[E0005]: refutable pattern in local binding: `None` not covered
+error[E0005]: refutable pattern in local binding
+(エラー: ローカル束縛に論駁可能なパターン)
  --> src/main.rs:3:9
   |
 3 |     let Some(x) = some_option_value;
   |         ^^^^^^^ pattern `None` not covered
+  |                (パターン`None`がカバーされていません)
   |
   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   (注釈: `let`束縛は`struct`や単一の列挙子を持つ`enum`などの「論駁不可能なパターン」を必要とします)
   = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
-help: you might want to use `if let` to ignore the variant that isn't matched
+   (注釈: さらなる情報についてはhttps://doc.rust-lang.org/book/ch18-02-refutability.htmlを確認してください)
+  = note: the matched value is of type `Option<i32>`
+   (注釈: マッチ対象の値は`Option<i32>`型を持ちます)
+help: you might want to use `let else` to handle the variant that isn't matched
+(ヘルプ: マッチしない列挙子を処理するために`let else`を使用するといいかもしれません)
   |
-3 |     if let Some(x) = some_option_value { /* */ }
-  |
-
-error: aborting due to previous error
+3 |     let Some(x) = some_option_value else { todo!() };
+  |                                     ++++++++++++++++
 
 For more information about this error, try `rustc --explain E0005`.
-error: could not compile `patterns`.
-
-To learn more, run the command again with --verbose.
+error: could not compile `patterns` (bin "patterns") due to 1 previous error

listings/ch18-patterns-and-matching/listing-18-09/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-10/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-10/output.txt

@@ -1,15 +1,20 @@
 $ cargo run
    Compiling patterns v0.1.0 (file:///projects/patterns)
-warning: irrefutable if-let pattern
- --> src/main.rs:2:5
+warning: irrefutable `if let` pattern
+(警告: 論駁不可能な`if let`パターン)
+ --> src/main.rs:2:8
   |
-2 | /     if let x = 5 {
-3 | |         println!("{}", x);
-4 | |     };
-  | |_____^
+2 |     if let x = 5 {
+  |        ^^^^^^^^^
   |
+  = note: this pattern will always match, so the `if let` is useless
+   (注釈: このパターンは常にマッチするので`if let`は無意味です)
+  = help: consider replacing the `if let` with a `let`
+   (ヘルプ: `if let`を`let`で置き換えることを検討してください)
   = note: `#[warn(irrefutable_let_patterns)]` on by default
+   (注釈: `#[warn(irrefutable_let_patterns)]`はデフォルトでオンです)
 
+warning: `patterns` (bin "patterns") generated 1 warning
     Finished dev [unoptimized + debuginfo] target(s) in 0.39s
      Running `target/debug/patterns`
 5

listings/ch18-patterns-and-matching/listing-18-11/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-11/src/main.rs

@@ -4,11 +4,15 @@ fn main() {
     let y = 10;
 
     match x {
+        // 50だったよ
         Some(50) => println!("Got 50"),
-        Some(y) => println!("Matched, y = {:?}", y),
+        // マッチしたよ、y = {y}
+        Some(y) => println!("Matched, y = {y}"),
+        // 既定のケース、x = {:?}
         _ => println!("Default case, x = {:?}", x),
     }
 
-    println!("at the end: x = {:?}, y = {:?}", x, y);
+    // 最後には: x = {:?}, y = {y}
+    println!("at the end: x = {:?}, y = {y}", x);
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-12/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-13/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-14/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-14/src/main.rs

@@ -8,9 +8,14 @@ fn main() {
     let p = Point { x: 0, y: 7 };
 
     match p {
-        Point { x, y: 0 } => println!("On the x axis at {}", x),
-        Point { x: 0, y } => println!("On the y axis at {}", y),
-        Point { x, y } => println!("On neither axis: ({}, {})", x, y),
+        // x軸上の{x}
+        Point { x, y: 0 } => println!("On the x axis at {x}"),
+        // y軸上の{y}
+        Point { x: 0, y } => println!("On the y axis at {y}"),
+        // どちらの軸上でもない: ({x}, {y})
+        Point { x, y } => {
+            println!("On neither axis: ({x}, {y})");
+        }
     }
 }
 // ANCHOR_END: here

listings/ch18-patterns-and-matching/listing-18-15/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-15/src/main.rs

@@ -10,18 +10,20 @@ fn main() {
 
     match msg {
         Message::Quit => {
-            println!("The Quit variant has no data to destructure.")
+            // Quit列挙子には分配すべきデータがない
+            println!("The Quit variant has no data to destructure.");
         }
         Message::Move { x, y } => {
-            println!(
-                "Move in the x direction {} and in the y direction {}",
-                x, y
-            );
+            // x方向に{x}、y方向に{y}だけ動く
+            println!("Move in the x direction {x} and in the y direction {y}");
+        }
+        Message::Write(text) => {
+            // テキストメッセージ: {text}
+            println!("Text message: {text}");
+        }
+        Message::ChangeColor(r, g, b) => {
+            // 色を赤{r}, 緑{g}, 青{b}に変更
+            println!("Change the color to red {r}, green {g}, and blue {b}",)
         }
-        Message::Write(text) => println!("Text message: {}", text),
-        Message::ChangeColor(r, g, b) => println!(
-            "Change the color to red {}, green {}, and blue {}",
-            r, g, b
-        ),
     }
 }

listings/ch18-patterns-and-matching/listing-18-16/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-16/src/main.rs

@@ -14,14 +14,14 @@ fn main() {
     let msg = Message::ChangeColor(Color::Hsv(0, 160, 255));
 
     match msg {
-        Message::ChangeColor(Color::Rgb(r, g, b)) => println!(
-            "Change the color to red {}, green {}, and blue {}",
-            r, g, b
-        ),
-        Message::ChangeColor(Color::Hsv(h, s, v)) => println!(
-            "Change the color to hue {}, saturation {}, and value {}",
-            h, s, v
-        ),
+        Message::ChangeColor(Color::Rgb(r, g, b)) => {
+            // 色を赤{r}, 緑{g}, 青{b}に変更
+            println!("Change color to red {r}, green {g}, and blue {b}");
+        }
+        Message::ChangeColor(Color::Hsv(h, s, v)) => {
+        	// 色を色相{h}, 彩度{s}, 明度{v}に変更
+            println!("Change color to hue {h}, saturation {s}, value {v}")
+        }
         _ => (),
     }
 }

listings/ch18-patterns-and-matching/listing-18-17/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-17/src/main.rs

@@ -1,4 +1,5 @@
 fn foo(_: i32, y: i32) {
+    // このコードは、y引数を使うだけです: {}
     println!("This code only uses the y parameter: {}", y);
 }
 

listings/ch18-patterns-and-matching/listing-18-18/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch18-patterns-and-matching/listing-18-18/src/main.rs

@@ -5,13 +5,15 @@ fn main() {
 
     match (setting_value, new_setting_value) {
         (Some(_), Some(_)) => {
+            // 既存の値の変更を上書きできません
             println!("Can't overwrite an existing customized value");
         }
         _ => {
             setting_value = new_setting_value;
         }
     }
 
+    // 設定は{:?}です
     println!("setting is {:?}", setting_value);
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-19/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "patterns"
 version = "0.1.0"
-authors = ["Your Name <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]