      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194

    //! All of the **marker traits** used in typenum.
    //!
    //! Note that the definition here for marker traits is slightly different than
    //! the conventional one -- we include traits with functions that convert a type
    //! to the corresponding value, as well as associated constants that do the
    //! same.
    //!
    //! For example, the `Integer` trait includes the function (among others) `fn
    //! to_i32() -> i32` and the associated constant `I32` so that one can do this:
    //!
    //! ```
    //! use typenum::{N42, Integer};
    //!
    //! assert_eq!(-42, N42::to_i32());
    //! assert_eq!(-42, N42::I32);
    //! ```
    //!

    /// A **marker trait** to designate that a type is not zero. All number types in this
    /// crate implement `NonZero` except `B0`, `U0`, and `Z0`.
    pub trait NonZero {}

    /// A **Marker trait** for the types `Greater`, `Equal`, and `Less`.
    ///
    /// This trait should not be implemented for anything outside this crate.
    pub trait Ord {
        #[allow(missing_docs)]
        fn to_ordering() -> ::core::cmp::Ordering;
    }

    /// The **marker trait** for compile time bits.
    ///
    /// This trait should not be implemented for anything outside this crate.
    pub trait Bit: Copy + Default {
        #[allow(missing_docs)]
        const U8: u8;
        #[allow(missing_docs)]
        const BOOL: bool;

        #[allow(missing_docs)]
        fn to_u8() -> u8;
        #[allow(missing_docs)]
        fn to_bool() -> bool;
    }

    /// The **marker trait** for compile time unsigned integers.
    ///
    /// This trait should not be implemented for anything outside this crate.
    ///
    /// # Example
    /// ```rust
    /// use typenum::{U3, Unsigned};
    ///
    /// assert_eq!(U3::to_u32(), 3);
    /// assert_eq!(U3::I32, 3);
    /// ```
    pub trait Unsigned: Copy + Default {
        #[allow(missing_docs)]
        const U8: u8;
        #[allow(missing_docs)]
        const U16: u16;
        #[allow(missing_docs)]
        const U32: u32;
        #[allow(missing_docs)]
        const U64: u64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        const U128: u128;
        #[allow(missing_docs)]
        const USIZE: usize;

        #[allow(missing_docs)]
        const I8: i8;
        #[allow(missing_docs)]
        const I16: i16;
        #[allow(missing_docs)]
        const I32: i32;
        #[allow(missing_docs)]
        const I64: i64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        const I128: i128;
        #[allow(missing_docs)]
        const ISIZE: isize;

        #[allow(missing_docs)]
        fn to_u8() -> u8;
        #[allow(missing_docs)]
        fn to_u16() -> u16;
        #[allow(missing_docs)]
        fn to_u32() -> u32;
        #[allow(missing_docs)]
        fn to_u64() -> u64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        fn to_u128() -> u128;
        #[allow(missing_docs)]
        fn to_usize() -> usize;

        #[allow(missing_docs)]
        fn to_i8() -> i8;
        #[allow(missing_docs)]
        fn to_i16() -> i16;
        #[allow(missing_docs)]
        fn to_i32() -> i32;
        #[allow(missing_docs)]
        fn to_i64() -> i64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        fn to_i128() -> i128;
        #[allow(missing_docs)]
        fn to_isize() -> isize;
    }

    /// The **marker trait** for compile time signed integers.
    ///
    /// This trait should not be implemented for anything outside this crate.
    ///
    /// # Example
    /// ```rust
    /// use typenum::{P3, Integer};
    ///
    /// assert_eq!(P3::to_i32(), 3);
    /// assert_eq!(P3::I32, 3);
    /// ```
    pub trait Integer {
        #[allow(missing_docs)]
        const I8: i8;
        #[allow(missing_docs)]
        const I16: i16;
        #[allow(missing_docs)]
        const I32: i32;
        #[allow(missing_docs)]
        const I64: i64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        const I128: i128;
        #[allow(missing_docs)]
        const ISIZE: isize;

        #[allow(missing_docs)]
        fn to_i8() -> i8;
        #[allow(missing_docs)]
        fn to_i16() -> i16;
        #[allow(missing_docs)]
        fn to_i32() -> i32;
        #[allow(missing_docs)]
        fn to_i64() -> i64;
        #[cfg(feature = "i128")]
        #[allow(missing_docs)]
        fn to_i128() -> i128;
        #[allow(missing_docs)]
        fn to_isize() -> isize;
    }

    /// The **marker trait** for type-level arrays of type-level numbers.
    ///
    /// This trait should not be implemented for anything outside this crate.
    ///
    /// Someday, it may contain an associated constant to produce a runtime array,
    /// like the other marker traits here. However, that is blocked by [this
    /// issue](https://github.com/rust-lang/rust/issues/44168).
    pub trait TypeArray {}

    /// The **marker trait** for type-level numbers which are a power of two.
    ///
    /// This trait should not be implemented for anything outside this crate.
    ///
    /// # Examples
    ///
    /// Here's a working example:
    ///
    /// ```rust
    /// use typenum::{P4, P8, PowerOfTwo};
    ///
    /// fn only_p2<P: PowerOfTwo>() { }
    ///
    /// only_p2::<P4>();
    /// only_p2::<P8>();
    /// ```
    ///
    /// Numbers which are not a power of two will fail to compile in this example:
    ///
    /// ```rust,compile_fail
    /// use typenum::{P9, P511, P1023, PowerOfTwo};
    ///
    /// fn only_p2<P: PowerOfTwo>() { }
    ///
    /// only_p2::<P9>();
    /// only_p2::<P511>();
    /// only_p2::<P1023>();
    /// ```

    pub trait PowerOfTwo {}