diff options
| -rw-r--r-- | library/core/src/char/methods.rs | 52 |
1 files changed, 51 insertions, 1 deletions
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs index 515b8d20ead..4ac956e7b76 100644 --- a/library/core/src/char/methods.rs +++ b/library/core/src/char/methods.rs @@ -9,8 +9,58 @@ use crate::unicode::{self, conversions}; use super::*; impl char { + /// The lowest valid code point a `char` can have, `'\0'`. + /// + /// Unlike integer types, `char` actually has a gap in the middle, + /// meaning that the range of possible `char`s is smaller than you + /// might expect. Ranges of `char` will automatically hop this gap + /// for you: + /// + /// ``` + /// #![feature(char_min)] + /// let dist = u32::from(char::MAX) - u32::from(char::MIN); + /// let size = (char::MIN..=char::MAX).count() as u32; + /// assert!(size < dist); + /// ``` + /// + /// Despite this gap, the `MIN` and [`MAX`] values can be used as bounds for + /// all `char` values. + /// + /// [`MAX`]: char::MAX + /// + /// # Examples + /// + /// ``` + /// #![feature(char_min)] + /// # fn something_which_returns_char() -> char { 'a' } + /// let c: char = something_which_returns_char(); + /// assert!(char::MIN <= c); + /// + /// let value_at_min = u32::from(char::MIN); + /// assert_eq!(char::from_u32(value_at_min), Some('\0')); + /// ``` + #[unstable(feature = "char_min", issue = "114298")] + pub const MIN: char = '\0'; + /// The highest valid code point a `char` can have, `'\u{10FFFF}'`. /// + /// Unlike integer types, `char` actually has a gap in the middle, + /// meaning that the range of possible `char`s is smaller than you + /// might expect. Ranges of `char` will automatically hop this gap + /// for you: + /// + /// ``` + /// #![feature(char_min)] + /// let dist = u32::from(char::MAX) - u32::from(char::MIN); + /// let size = (char::MIN..=char::MAX).count() as u32; + /// assert!(size < dist); + /// ``` + /// + /// Despite this gap, the [`MIN`] and `MAX` values can be used as bounds for + /// all `char` values. + /// + /// [`MIN`]: char::MIN + /// /// # Examples /// /// ``` @@ -18,7 +68,7 @@ impl char { /// let c: char = something_which_returns_char(); /// assert!(c <= char::MAX); /// - /// let value_at_max = char::MAX as u32; + /// let value_at_max = u32::from(char::MAX); /// assert_eq!(char::from_u32(value_at_max), Some('\u{10FFFF}')); /// assert_eq!(char::from_u32(value_at_max + 1), None); /// ``` |