2 releases
0.1.1 | Apr 2, 2020 |
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0.1.0 | Apr 2, 2020 |
#2055 in Rust patterns
467 downloads per month
4KB
to_trait
Provides the To
trait, which provides methods similar to .into()
and .try_into()
, except they take type arguments. The trait looks like this:
trait To {
fn to<T>(self) -> T where Self: Into<T>;
fn try_to<T>(self) -> Result<T, Self::Error> where Self: TryInto<T>;
}
and you use it like this:
use to_trait::To;
let five_u64 = 5u32.to::<u64>();
let five_u8 = 5u32.to::<u8>().unwrap();
At first glance, this might not seem very useful, but sometimes the compiler can't infer the output type of a call to .into()
. This happens a lot with method chains, e.g. if you call .into().some_other_method()
, and it can be pretty annoying.
What woud be ideal is if we could write the desired output type as type arguments to the method. Unfortunately, because Into<T>
takes T
as a trait type parameter, we can't supply it when calling the method - the only way to supply the type arguments is by falling back to universal function call syntax, with Into::<T>::into(..)
.
The methods on To
trait essentially act as type inference helpers, letting you supply the type arguments while still using method call syntax. As a bonus, they are shorter by two characters 😄
License
MIT