std.ascii | Zero

When To Use std.ascii

In Zerolang, use std.ascii when a program needs byte-level ASCII predicates, case conversion, or digit values without Unicode normalization.

Runnable today:

API	Return	Notes
`std.ascii.isDigit(byte)`	`Bool`	Checks `0` through `9`.
`std.ascii.isAlpha(byte)`	`Bool`	Checks `A` through `Z` or `a` through `z`.
`std.ascii.isAlnum(byte)`	`Bool`	Checks ASCII alphabetic or digit bytes.
`std.ascii.isWhitespace(byte)`	`Bool`	Checks space, tab, line feed, and carriage return.
`std.ascii.isLower(byte)` / `std.ascii.isUpper(byte)`	`Bool`	Checks ASCII case ranges.
`std.ascii.isHexDigit(byte)`	`Bool`	Checks decimal digits and `a-f` / `A-F`.
`std.ascii.toLower(byte)` / `std.ascii.toUpper(byte)`	`u8`	Converts ASCII letters and leaves other bytes unchanged.
`std.ascii.digitValue(byte)`	`Maybe<u8>`	Converts an ASCII decimal digit to `0..9`.
`std.ascii.hexValue(byte)`	`Maybe<u8>`	Converts an ASCII hexadecimal digit to `0..15`.

Example

pub fn main(world: World) -> Void raises {    let digit: Maybe<u8> = std.ascii.digitValue(55_u8)    let hex: Maybe<u8> = std.ascii.hexValue(70_u8)    if std.ascii.isAlpha(65_u8) && std.ascii.toLower(90_u8) == 122_u8 && digit.has && digit.value == 7_u8 && hex.has && hex.value == 15_u8 {        check world.out.write("ascii ok\n")    }}

Effects: none.

Allocation behavior: no allocation.

Error behavior: value helpers return null when the byte is outside the accepted range.

Target support: current compiler targets.