fix: use trait objects for from_str

Use `Box<dyn error::Error>` to allow solutions to use `?` to propagate 
errors.
This commit is contained in:
Taylor Yu 2021-04-04 18:43:38 -05:00
parent 2e93a588e0
commit c3e7b83178
2 changed files with 3 additions and 2 deletions

View File

@ -2,6 +2,7 @@
// Additionally, upon implementing FromStr, you can use the `parse` method // Additionally, upon implementing FromStr, you can use the `parse` method
// on strings to generate an object of the implementor type. // on strings to generate an object of the implementor type.
// You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html // You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
use std::error;
use std::str::FromStr; use std::str::FromStr;
#[derive(Debug)] #[derive(Debug)]
@ -23,7 +24,7 @@ struct Person {
// If everything goes well, then return a Result of a Person object // If everything goes well, then return a Result of a Person object
impl FromStr for Person { impl FromStr for Person {
type Err = String; type Err = Box<dyn error::Error>;
fn from_str(s: &str) -> Result<Person, Self::Err> { fn from_str(s: &str) -> Result<Person, Self::Err> {
} }
} }

View File

@ -884,5 +884,5 @@ path = "exercises/conversions/from_str.rs"
mode = "test" mode = "test"
hint = """ hint = """
The implementation of FromStr should return an Ok with a Person object, The implementation of FromStr should return an Ok with a Person object,
or an Err with a string if the string is not valid. or an Err with an error if the string is not valid.
This is almost like the `try_from_into` exercise.""" This is almost like the `try_from_into` exercise."""