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Code Issues Releases Activity

Implement Error.

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This commit is contained in:
Andrew Walbran 2023-01-16 17:53:43 +00:00
parent caaca140ca
commit 27b6165202
1 changed files with 13 additions and 0 deletions
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13
src/error-handling/converting-error-types.md
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@ -19,8 +19,10 @@ The `From::from` call here means we attempt to convert the error type to the
type returned by the function:
```rust,editable
use std::error::Error;
use std::{fs, io};
use std::io::Read;
use std::fmt::{self, Display, Formatter};
#[derive(Debug)]
enum ReadUsernameError {
@ -28,6 +30,17 @@ enum ReadUsernameError {
EmptyUsername(String),
}
impl Error for ReadUsernameError {}
impl Display for ReadUsernameError {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self {
Self::IoError(e) => write!(f, "IO error: {}", e),
Self::EmptyUsername(filename) => write!(f, "Found no username in {}", filename),
}
}
}
impl From<io::Error> for ReadUsernameError {
fn from(err: io::Error) -> ReadUsernameError {
ReadUsernameError::IoError(err)