Enum core::ascii::Char

source ·

#[repr(u8)]pub enum Char {
Show 128 variants    Null,
    StartOfHeading,
    StartOfText,
    EndOfText,
    EndOfTransmission,
    Enquiry,
    Acknowledge,
    Bell,
    Backspace,
    CharacterTabulation,
    LineFeed,
    LineTabulation,
    FormFeed,
    CarriageReturn,
    ShiftOut,
    ShiftIn,
    DataLinkEscape,
    DeviceControlOne,
    DeviceControlTwo,
    DeviceControlThree,
    DeviceControlFour,
    NegativeAcknowledge,
    SynchronousIdle,
    EndOfTransmissionBlock,
    Cancel,
    EndOfMedium,
    Substitute,
    Escape,
    InformationSeparatorFour,
    InformationSeparatorThree,
    InformationSeparatorTwo,
    InformationSeparatorOne,
    Space,
    ExclamationMark,
    QuotationMark,
    NumberSign,
    DollarSign,
    PercentSign,
    Ampersand,
    Apostrophe,
    LeftParenthesis,
    RightParenthesis,
    Asterisk,
    PlusSign,
    Comma,
    HyphenMinus,
    FullStop,
    Solidus,
    Digit0,
    Digit1,
    Digit2,
    Digit3,
    Digit4,
    Digit5,
    Digit6,
    Digit7,
    Digit8,
    Digit9,
    Colon,
    Semicolon,
    LessThanSign,
    EqualsSign,
    GreaterThanSign,
    QuestionMark,
    CommercialAt,
    CapitalA,
    CapitalB,
    CapitalC,
    CapitalD,
    CapitalE,
    CapitalF,
    CapitalG,
    CapitalH,
    CapitalI,
    CapitalJ,
    CapitalK,
    CapitalL,
    CapitalM,
    CapitalN,
    CapitalO,
    CapitalP,
    CapitalQ,
    CapitalR,
    CapitalS,
    CapitalT,
    CapitalU,
    CapitalV,
    CapitalW,
    CapitalX,
    CapitalY,
    CapitalZ,
    LeftSquareBracket,
    ReverseSolidus,
    RightSquareBracket,
    CircumflexAccent,
    LowLine,
    GraveAccent,
    SmallA,
    SmallB,
    SmallC,
    SmallD,
    SmallE,
    SmallF,
    SmallG,
    SmallH,
    SmallI,
    SmallJ,
    SmallK,
    SmallL,
    SmallM,
    SmallN,
    SmallO,
    SmallP,
    SmallQ,
    SmallR,
    SmallS,
    SmallT,
    SmallU,
    SmallV,
    SmallW,
    SmallX,
    SmallY,
    SmallZ,
    LeftCurlyBracket,
    VerticalLine,
    RightCurlyBracket,
    Tilde,
    Delete,
}

🔬This is a nightly-only experimental API. (ascii_char #110998)

Expand description

One of the 128 Unicode characters from U+0000 through U+007F, often known as the ASCII subset.

Officially, this is the first block in Unicode, Basic Latin. For details, see the C0 Controls and Basic Latin code chart.

This block was based on older 7-bit character code standards such as ANSI X3.4-1977, ISO 646-1973, and NIST FIPS 1-2.

When to use this

The main advantage of this subset is that it’s always valid UTF-8. As such, the &[ascii::Char] -> &str conversion function (as well as other related ones) are O(1): no runtime checks are needed.

If you’re consuming strings, you should usually handle Unicode and thus accept strs, not limit yourself to ascii::Chars.

However, certain formats are intentionally designed to produce ASCII-only output in order to be 8-bit-clean. In those cases, it can be simpler and faster to generate ascii::Chars instead of dealing with the variable width properties of general UTF-8 encoded strings, while still allowing the result to be used freely with other Rust things that deal in general strs.

For example, a UUID library might offer a way to produce the string representation of a UUID as an [ascii::Char; 36] to avoid memory allocation yet still allow it to be used as UTF-8 via as_str without paying for validation (or needing unsafe code) the way it would if it were provided as a [u8; 36].

Layout

This type is guaranteed to have a size and alignment of 1 byte.

Names

The variants on this type are Unicode names of the characters in upper camel case, with a few tweaks:

For <control> characters, the primary alias name is used.
LATIN is dropped, as this block has no non-latin letters.
LETTER is dropped, as CAPITAL/SMALL suffices in this block.
DIGITs use a single digit rather than writing out ZERO, ONE, etc.