ch09 エラー処理の和訳を最新版に更新

rust-lang/book@19c40bf

Author: shinmili

listings/ch09-error-handling/listing-09-01/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "panic"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-01/output.txt

@@ -2,5 +2,8 @@ $ cargo run
    Compiling panic v0.1.0 (file:///projects/panic)
     Finished dev [unoptimized + debuginfo] target(s) in 0.27s
      Running `target/debug/panic`
-thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 99', /rustc/5e1a799842ba6ed4a57e91f7ab9435947482f7d8/src/libcore/slice/mod.rs:2806:10
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at src/main.rs:4:6:
+index out of bounds: the len is 3 but the index is 99
+('main'スレッドはsrc/main.rs:4:6でパニックしました:
+境界外番号: 長さは3なのに、添え字は99です)
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

listings/ch09-error-handling/listing-09-03/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-03/src/main.rs

@@ -1,5 +1,5 @@
 use std::fs::File;
 
 fn main() {
-    let f = File::open("hello.txt");
+    let greeting_file_result = File::open("hello.txt");
 }

listings/ch09-error-handling/listing-09-04/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-04/output.txt

@@ -2,5 +2,8 @@ $ cargo run
    Compiling error-handling v0.1.0 (file:///projects/error-handling)
     Finished dev [unoptimized + debuginfo] target(s) in 0.73s
      Running `target/debug/error-handling`
-thread 'main' panicked at 'Problem opening the file: Os { code: 2, kind: NotFound, message: "No such file or directory" }', src/main.rs:8:23
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at src/main.rs:8:23:
+Problem opening the file: Os { code: 2, kind: NotFound, message: "No such file or directory" }
+('main'スレッドは、src/main.rs:8:23でパニックしました:
+ファイルを開く際に問題がありました: Os { code: 2, kind: NotFound, message: "そのようなファイルやディレクトリはありません" })
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

listings/ch09-error-handling/listing-09-04/src/main.rs

@@ -1,10 +1,11 @@
 use std::fs::File;
 
 fn main() {
-    let f = File::open("hello.txt");
+    let greeting_file_result = File::open("hello.txt");
 
-    let f = match f {
+    let greeting_file = match greeting_file_result {
         Ok(file) => file,
+        //                   "ファイルを開くのに問題がありました: {:?}"
         Err(error) => panic!("Problem opening the file: {:?}", error),
     };
 }

listings/ch09-error-handling/listing-09-05/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-05/src/main.rs

@@ -2,17 +2,19 @@ use std::fs::File;
 use std::io::ErrorKind;
 
 fn main() {
-    let f = File::open("hello.txt");
+    let greeting_file_result = File::open("hello.txt");
 
-    let f = match f {
+    let greeting_file = match greeting_file_result {
         Ok(file) => file,
         Err(error) => match error.kind() {
             ErrorKind::NotFound => match File::create("hello.txt") {
                 Ok(fc) => fc,
+                //               "ファイルを作成するのに問題がありました: {:?}"
                 Err(e) => panic!("Problem creating the file: {:?}", e),
             },
             other_error => {
-                panic!("Problem opening the file: {:?}", other_error)
+                //     "ファイルを開くのに問題がありました: {:?}"
+                panic!("Problem opening the file: {:?}", other_error);
             }
         },
     };

listings/ch09-error-handling/listing-09-06/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-06/src/main.rs

@@ -1,20 +1,19 @@
 // ANCHOR: here
 use std::fs::File;
-use std::io;
-use std::io::Read;
+use std::io::{self, Read};
 
 fn read_username_from_file() -> Result<String, io::Error> {
-    let f = File::open("hello.txt");
+    let username_file_result = File::open("hello.txt");
 
-    let mut f = match f {
+    let mut username_file = match username_file_result {
         Ok(file) => file,
         Err(e) => return Err(e),
     };
 
-    let mut s = String::new();
+    let mut username = String::new();
 
-    match f.read_to_string(&mut s) {
-        Ok(_) => Ok(s),
+    match username_file.read_to_string(&mut username) {
+        Ok(_) => Ok(username),
         Err(e) => Err(e),
     }
 }

listings/ch09-error-handling/listing-09-07/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-07/src/main.rs

@@ -1,13 +1,12 @@
 // ANCHOR: here
 use std::fs::File;
-use std::io;
-use std::io::Read;
+use std::io::{self, Read};
 
 fn read_username_from_file() -> Result<String, io::Error> {
-    let mut f = File::open("hello.txt")?;
-    let mut s = String::new();
-    f.read_to_string(&mut s)?;
-    Ok(s)
+    let mut username_file = File::open("hello.txt")?;
+    let mut username = String::new();
+    username_file.read_to_string(&mut username)?;
+    Ok(username)
 }
 // ANCHOR_END: here
 

listings/ch09-error-handling/listing-09-08/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-08/src/main.rs

@@ -1,14 +1,13 @@
 // ANCHOR: here
 use std::fs::File;
-use std::io;
-use std::io::Read;
+use std::io::{self, Read};
 
 fn read_username_from_file() -> Result<String, io::Error> {
-    let mut s = String::new();
+    let mut username = String::new();
 
-    File::open("hello.txt")?.read_to_string(&mut s)?;
+    File::open("hello.txt")?.read_to_string(&mut username)?;
 
-    Ok(s)
+    Ok(username)
 }
 // ANCHOR_END: here
 

listings/ch09-error-handling/listing-09-09/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

listings/ch09-error-handling/listing-09-10/Cargo.lock

@@ -1,8 +1,6 @@
 [package]
-name = "guessing_game"
+name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
-rand = "0.5.5"

listings/ch09-error-handling/listing-09-10/Cargo.toml

@@ -0,0 +1,18 @@
+$ cargo run
+   Compiling error-handling v0.1.0 (file:///projects/error-handling)
+error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
+(エラー: `?`演算子は`Result`または`Option`(あるいはその他`FromResidual`を実装する型)を返す関数内でのみ使用できます
+ --> src/main.rs:4:48
+  |
+3 | fn main() {
+  | --------- this function should return `Result` or `Option` to accept `?`
+             (`?`を使えるようにするには、この関数は`Result`または`Option`を返すべきです)
+4 |     let greeting_file = File::open("hello.txt")?;
+  |                                                ^ cannot use the `?` operator in a function that returns `()`
+                                                    (`()`を返す関数内では`?`演算子を使用できません)
+  |
+  = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
+   (ヘルプ: トレイト`FromResidual<Result<Infallible, std::io::Error>>`は`()`に対して実装されていません)
+
+For more information about this error, try `rustc --explain E0277`.
+error: could not compile `error-handling` (bin "error-handling") due to 1 previous error

listings/ch09-error-handling/listing-09-10/output.txt

@@ -1,55 +1,5 @@
-use rand::Rng;
-use std::cmp::Ordering;
-use std::io;
-
-// ANCHOR: here
-pub struct Guess {
-    value: i32,
-}
-
-impl Guess {
-    pub fn new(value: i32) -> Guess {
-        if value < 1 || value > 100 {
-            panic!("Guess value must be between 1 and 100, got {}.", value);
-        }
-
-        Guess { value }
-    }
-
-    pub fn value(&self) -> i32 {
-        self.value
-    }
-}
-// ANCHOR_END: here
+use std::fs::File;
 
 fn main() {
-    println!("Guess the number!");
-
-    let secret_number = rand::thread_rng().gen_range(1, 101);
-
-    loop {
-        println!("Please input your guess.");
-
-        let mut guess = String::new();
-
-        io::stdin()
-            .read_line(&mut guess)
-            .expect("Failed to read line");
-
-        let guess: i32 = match guess.trim().parse() {
-            Ok(num) => num,
-            Err(_) => continue,
-        };
-
-        let guess = Guess::new(guess);
-
-        match guess.value().cmp(&secret_number) {
-            Ordering::Less => println!("Too small!"),
-            Ordering::Greater => println!("Too big!"),
-            Ordering::Equal => {
-                println!("You win!");
-                break;
-            }
-        }
-    }
+    let greeting_file = File::open("hello.txt")?;
 }

listings/ch09-error-handling/listing-09-10/src/main.rs

@@ -1,7 +1,6 @@
 [package]
 name = "error-handling"
 version = "0.1.0"
-authors = ["Your Name <you@example.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]