diff options
Diffstat (limited to 'library/core/src')
| -rw-r--r-- | library/core/src/convert/num.rs | 50 |
1 files changed, 48 insertions, 2 deletions
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs index 0246d0627ca..d5cb10a5d1c 100644 --- a/library/core/src/convert/num.rs +++ b/library/core/src/convert/num.rs @@ -147,22 +147,42 @@ impl_from!(i16 => isize, #[stable(feature = "lossless_iusize_conv", since = "1.2 // https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-951.pdf // Note: integers can only be represented with full precision in a float if -// they fit in the significand, which is 24 bits in f32 and 53 bits in f64. +// they fit in the significand, which is: +// * 11 bits in f16 +// * 24 bits in f32 +// * 53 bits in f64 +// * 113 bits in f128 // Lossy float conversions are not implemented at this time. +// FIXME(f16_f128): The `f16`/`f128` impls `#[stable]` attributes should be changed to reference +// `f16`/`f128` when they are stabilised (trait impls have to have a `#[stable]` attribute, but none +// of the `f16`/`f128` impls can be used on stable as the `f16` and `f128` types are unstable). // signed integer -> float +impl_from!(i8 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(i8 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(i8 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(i8 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(i16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(i16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(i16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(i32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(i32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +// FIXME(f16_f128): This impl would allow using `f128` on stable before it is stabilised. +// impl_from!(i64 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); // unsigned integer -> float +impl_from!(u8 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(u8 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(u8 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(u8 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(u16 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(u16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(u16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(u16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); impl_from!(u32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +impl_from!(u32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); +// FIXME(f16_f128): This impl would allow using `f128` on stable before it is stabilised. +// impl_from!(u64 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); // float -> float // FIXME(f16_f128): adding additional `From<{float}>` impls to `f32` breaks inference. See @@ -174,7 +194,12 @@ impl_from!(f32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0 impl_from!(f64 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]); macro_rules! impl_float_from_bool { - ($float:ty) => { + ( + $float:ty $(; + doctest_prefix: $(#[doc = $doctest_prefix:literal])* + doctest_suffix: $(#[doc = $doctest_suffix:literal])* + )? + ) => { #[stable(feature = "float_from_bool", since = "1.68.0")] impl From<bool> for $float { #[doc = concat!("Converts a [`bool`] to [`", stringify!($float),"`] losslessly.")] @@ -182,12 +207,14 @@ macro_rules! impl_float_from_bool { /// /// # Examples /// ``` + $($(#[doc = $doctest_prefix])*)? #[doc = concat!("let x: ", stringify!($float)," = false.into();")] /// assert_eq!(x, 0.0); /// assert!(x.is_sign_positive()); /// #[doc = concat!("let y: ", stringify!($float)," = true.into();")] /// assert_eq!(y, 1.0); + $($(#[doc = $doctest_suffix])*)? /// ``` #[inline] fn from(small: bool) -> Self { @@ -198,8 +225,27 @@ macro_rules! impl_float_from_bool { } // boolean -> float +impl_float_from_bool!( + f16; + doctest_prefix: + // rustdoc doesn't remove the conventional space after the `///` + ///#![feature(f16)] + ///# #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + doctest_suffix: + ///# } +); impl_float_from_bool!(f32); impl_float_from_bool!(f64); +impl_float_from_bool!( + f128; + doctest_prefix: + ///#![feature(f128)] + ///# #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + doctest_suffix: + ///# } +); // no possible bounds violation macro_rules! impl_try_from_unbounded { |