Struct const_panic::fmt::ComputePvCount

pub struct ComputePvCount {
    pub field_amount: usize,
    pub summed_pv_count: usize,
    pub delimiter: TypeDelim,
}

Available on crate feature non_basic only.

For computing the PanicFmt::PV_COUNT of a struct or enum variant, with the call method.

This assumes that you write the to_panicvals method like in the flatten_panicvals examples

Examples

These examples demonstrates how to use this type by itself, for a more complete example you can look at the flatten_panicvals examples

Struct

use const_panic::{ComputePvCount, PanicFmt};

struct Foo<'a> {
    x: u32,
    y: &'a [&'a str],
    z: Bar,
}

impl PanicFmt for Foo<'_> {
    type This = Self;
    type Kind = const_panic::IsCustomType;
     
    const PV_COUNT: usize = ComputePvCount{
        field_amount: 3,
        summed_pv_count:
            u32::PV_COUNT +
            <&[&str]>::PV_COUNT +
            <Bar>::PV_COUNT,
        delimiter: const_panic::TypeDelim::Braced,
    }.call();
}

assert_eq!(Foo::PV_COUNT, 12);

Enum

use const_panic::{ComputePvCount, PanicFmt};

enum Foo {
    Bar,
    Baz(u32, u64),
}

impl PanicFmt for Foo {
    type This = Self;
    type Kind = const_panic::IsCustomType;
     
    const PV_COUNT: usize = const_panic::utils::slice_max_usize(&[
        ComputePvCount{
            field_amount: 0,
            summed_pv_count: 0,
            delimiter: const_panic::TypeDelim::Braced,
        }.call(),
        ComputePvCount{
            field_amount: 2,
            summed_pv_count: <u32>::PV_COUNT + <u64>::PV_COUNT,
            delimiter: const_panic::TypeDelim::Tupled,
        }.call(),
    ]);
}

assert_eq!(Foo::PV_COUNT, 7);

Fields

field_amount: usize

The amount of fields in the struct

summed_pv_count: usize

The summed up amount of PanicVals that all the fields produce.

Eg: for a struct with Bar and Qux fields, this would be <Bar as PanicFmt>::PV_COUNT + <Qux as PanicFmt>::PV_COUNT,

delimiter: TypeDelim

Whether it’s a tupled or braced struct/variant.

Implementations

impl ComputePvCount

pub const fn call(&self) -> usize

Does the computation.