Errata in the Rust's book

1

Hello,

I'm studing Rust: what an interesting new language for me!

I found an errata in the Rust's book section 6.1

enum Message has WriteMessage as a member type.

However, the next code example says:
let m = Message::Write(String::from("hello"));

That's wrong, I think it must say:
let m = Message::WriteMessage(String::from("hello"));

That's all.

2

I'm not seeing this error, can you pinpoint the paragraph?

https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html

3

Its in this section at the end: Defining an Enum - The Rust Programming Language

But I don't think this is an error. First snippet defines Message as:

enum Message {
    Quit,
    Move { x: i32, y: i32 },
    Write(String),
    ChangeColor(i32, i32, i32),
}

which is correctly instantiated by:

let m = Message::Write(String::from("hello"));

from this snippet:

    impl Message {
        fn call(&self) {
            // method body would be defined here
        }
    }

    let m = Message::Write(String::from("hello"));
    m.call();

In between these snippets is the definition of a tuple struct:

struct WriteMessage(String); // tuple struct

which could be instantiated with:

let m = WriteMessage(String::from("hello"));

WriteMessage is a struct, not a member of the Message enum.

4

Ok,

I see.

Thank you.

Newbie rust student error.

5

No worries. This snippet is wrongly formatted (indentation-wise):

    impl Message {
        fn call(&self) {
            // method body would be defined here
        }
    }

    let m = Message::Write(String::from("hello"));
    m.call();

You could open a PR fixing the indentation :slightly_smiling_face:

... there are a lot of snippets on this page with leading indentation I just saw

6

Yes. I saw that, but I left open the possibility that I didn't see the error @jopeless saw.

1 Like
7

There was no error, I thought WriteMessage was a member of the enum and it is a struct written as another example. So, it was my fault.