Type Definition structural::enums::VariantCountOut

type VariantCountOut<This> = <This as VariantCount>::Count;

Queries the amount of variants of This.

This evaluates to a TStr,like TS!(9)

Example

This demonstrates VariantCountOut by making a function that requires two enums to have the same number of variants.

use structural::Structural;
use structural::enums::{VariantCount,VariantCountOut};

same_sized_enums( &Enum1::Foo, &Enum2::A );

// This does not compile because `Enum1` has 3 variants and `Result` has 2 variants.
// same_sized_enums( &Enum1::Foo, &Result::<(),()>::Ok(()) );

// This function asserts at compile-time that both enums have the same number of variants.
fn same_sized_enums<L,R>(left:&L,right:&R)
where
    L:VariantCount,
    R:VariantCount<Count=VariantCountOut<L>>,
{}

     
#[derive(Structural)]
enum Enum1{
    Foo,
    Bar,
    Baz,
}
     
#[derive(Structural)]
enum Enum2{
    A,
    B,
    C,
}