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4.3.0	2023 年 12 月 15 日
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106 在 Rust 模式中排名

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用于 683 个包 (直接使用 17 个)

MIT 许可证

19KB

Enum Ordinalize

此库允许枚举不仅能够获取其变体的序号值，还可以从序号值构造枚举。

用法

使用 #[derive(Ordinalize)] 以使枚举（只能有单元变体）实现 Ordinalize 特性。

use enum_ordinalize::Ordinalize;

#[derive(Debug, PartialEq, Eq, Ordinalize)]
enum MyEnum {
    Zero,
    One,
    Two,
}

assert_eq!(3, MyEnum::VARIANT_COUNT);
assert_eq!([MyEnum::Zero, MyEnum::One, MyEnum::Two], MyEnum::VARIANTS);
assert_eq!([0i8, 1i8, 2i8], MyEnum::VALUES);

assert_eq!(0i8, MyEnum::Zero.ordinal());
assert_eq!(1i8, MyEnum::One.ordinal());
assert_eq!(2i8, MyEnum::Two.ordinal());

assert_eq!(Some(MyEnum::Zero), MyEnum::from_ordinal(0i8));
assert_eq!(Some(MyEnum::One), MyEnum::from_ordinal(1i8));
assert_eq!(Some(MyEnum::Two), MyEnum::from_ordinal(2i8));

assert_eq!(MyEnum::Zero, unsafe { MyEnum::from_ordinal_unsafe(0i8) });
assert_eq!(MyEnum::One, unsafe { MyEnum::from_ordinal_unsafe(1i8) });
assert_eq!(MyEnum::Two, unsafe { MyEnum::from_ordinal_unsafe(2i8) });

枚举的大小

序号值是一个整数，其大小由枚举本身决定。枚举的大小随着变体值的幅度增加而增加，无论大小（或负值时更小）。

例如，

use enum_ordinalize::Ordinalize;

#[derive(Debug, PartialEq, Eq, Ordinalize)]
enum MyEnum {
    Zero,
    One,
    Two,
    Thousand = 1000,
}

assert_eq!(4, MyEnum::VARIANT_COUNT);
assert_eq!([MyEnum::Zero, MyEnum::One, MyEnum::Two, MyEnum::Thousand], MyEnum::VARIANTS);
assert_eq!([0i16, 1i16, 2i16, 1000i16], MyEnum::VALUES);

assert_eq!(0i16, MyEnum::Zero.ordinal());
assert_eq!(1i16, MyEnum::One.ordinal());
assert_eq!(2i16, MyEnum::Two.ordinal());

assert_eq!(Some(MyEnum::Zero), MyEnum::from_ordinal(0i16));
assert_eq!(Some(MyEnum::One), MyEnum::from_ordinal(1i16));
assert_eq!(Some(MyEnum::Two), MyEnum::from_ordinal(2i16));

assert_eq!(MyEnum::Zero, unsafe { MyEnum::from_ordinal_unsafe(0i16) });
assert_eq!(MyEnum::One, unsafe { MyEnum::from_ordinal_unsafe(1i16) });
assert_eq!(MyEnum::Two, unsafe { MyEnum::from_ordinal_unsafe(2i16) });

为了适应值 1000，MyEnum 的大小会增加。因此，序号用 i16 而不是 i8 表示。

您可以使用 #[repr(type)] 属性来显式控制大小。例如， use enum_ordinalize::Ordinalize; #[derive(Debug, PartialEq, Eq, Ordinalize)] #[repr(usize)] enum MyEnum { Zero, One, Two, Thousand = 1000, } assert_eq!(4, MyEnum::VARIANT_COUNT); assert_eq!([MyEnum::Zero, MyEnum::One, MyEnum::Two, MyEnum::Thousand], MyEnum::VARIANTS); assert_eq!([0usize, 1usize, 2usize, 1000usize], MyEnum::VALUES); assert_eq!(0usize, MyEnum::Zero.ordinal()); assert_eq!(1usize, MyEnum::One.ordinal()); assert_eq!(2usize, MyEnum::Two.ordinal()); assert_eq!(Some(MyEnum::Zero), MyEnum::from_ordinal(0usize)); assert_eq!(Some(MyEnum::One), MyEnum::from_ordinal(1usize)); assert_eq!(Some(MyEnum::Two), MyEnum::from_ordinal(2usize)); assert_eq!(MyEnum::Zero, unsafe { MyEnum::from_ordinal_unsafe(0usize) }); assert_eq!(MyEnum::One, unsafe { MyEnum::from_ordinal_unsafe(1usize) }); assert_eq!(MyEnum::Two, unsafe { MyEnum::from_ordinal_unsafe(2usize) }); 有用的增量变体表示的整数可以按顺序增加，并从任何值显式设置。 use enum_ordinalize::Ordinalize; #[derive(Debug, PartialEq, Eq, Ordinalize)] enum MyEnum { Two = 2, Three, Four, Eight = 8, Nine, NegativeTen = -10, NegativeNine, } assert_eq!(7, MyEnum::VARIANT_COUNT); assert_eq!([MyEnum::Two, MyEnum::Three, MyEnum::Four, MyEnum::Eight, MyEnum::Nine, MyEnum::NegativeTen, MyEnum::NegativeNine], MyEnum::VARIANTS); assert_eq!([2i8, 3i8, 4i8, 8i8, 9i8, -10i8, -9i8], MyEnum::VALUES); assert_eq!(4i8, MyEnum::Four.ordinal()); assert_eq!(9i8, MyEnum::Nine.ordinal()); assert_eq!(-9i8, MyEnum::NegativeNine.ordinal()); assert_eq!(Some(MyEnum::Four), MyEnum::from_ordinal(4i8)); assert_eq!(Some(MyEnum::Nine), MyEnum::from_ordinal(9i8)); assert_eq!(Some(MyEnum::NegativeNine), MyEnum::from_ordinal(-9i8)); assert_eq!(MyEnum::Four, unsafe { MyEnum::from_ordinal_unsafe(4i8) }); assert_eq!(MyEnum::Nine, unsafe { MyEnum::from_ordinal_unsafe(9i8) }); assert_eq!(MyEnum::NegativeNine, unsafe { MyEnum::from_ordinal_unsafe(-9i8) }); 为枚举实现自身上的功能出于某种原因，如果您不想为您的枚举实现 Ordinalize 特性，您可以选择禁用特性实现并逐个启用常量/函数。函数是 const fn。名称和可见性也可以由您定义。 use enum_ordinalize::Ordinalize; #[derive(Debug, PartialEq, Eq, Ordinalize)] #[ordinalize(impl_trait = false)] #[ordinalize(variant_count(pub const VARIANT_COUNT, doc = "The count of variants."))] #[ordinalize(variants(pub const VARIANTS, doc = "List of this enum's variants."))] #[ordinalize(values(pub const VALUES, doc = "List of values for all variants of this enum."))] #[ordinalize(ordinal(pub const fn ordinal, doc = "Retrieve the integer number of this variant."))] #[ordinalize(from_ordinal(pub const fn from_ordinal, doc = "Obtain a variant based on an integer number."))] #[ordinalize(from_ordinal_unsafe( pub const fn from_ordinal_unsafe, doc = "Obtain a variant based on an integer number.", doc = "# Safety", doc = "You have to ensure that the input integer number can correspond to a variant on your own.", ))] enum MyEnum { A, B, } assert_eq!(2, MyEnum::VARIANT_COUNT); assert_eq!([MyEnum::A, MyEnum::B], MyEnum::VARIANTS); assert_eq!([0i8, 1i8], MyEnum::VALUES); assert_eq!(0i8, MyEnum::A.ordinal()); assert_eq!(1i8, MyEnum::B.ordinal()); assert_eq!(Some(MyEnum::A), MyEnum::from_ordinal(0i8)); assert_eq!(Some(MyEnum::B), MyEnum::from_ordinal(1i8)); assert_eq!(MyEnum::A, unsafe { MyEnum::from_ordinal_unsafe(0i8) }); assert_eq!(MyEnum::B, unsafe { MyEnum::from_ordinal_unsafe(1i8) }); Crates.io https://crates.io/crates/enum-ordinalize 文档 https://docs.rs/enum-ordinalize 许可证 MIT

依赖项 ~110KB derive traits enum-ordinalize-derive 其他功能 nightly-test