char32

char32 is the standard Unicode character type, covering all 1,114,112 code points (U+0000–U+10FFFF) including emoji and the supplementary planes. The plain char keyword is an alias for it. Like all Rux character types it is an unsigned, non-nullable value type that holds a single code point or raw code unit, and is type-distinct from both integers and strings. It is the recommended type for general-purpose Unicode text.

Literals

A character literal is written with single quotes:

let octopus: char32 = '🐙';      // U+1F419
let math: char32 = '𝕳';          // U+1D573
let emoji: char32 = '\u{1F600}'; // U+1F600 😀 — Unicode escape

Escape Sequences

The \u{...} escape takes 1–6 hexadecimal digits (braces mandatory); values above U+10FFFF are rejected at compile time.

Typical Use Cases

• General Unicode text processing
• Code-point iteration over strings

Comparison

Character types are comparable for both equality and ordering. Ordering follows the numeric value of the underlying code point (code-point order, not locale-aware collation).

let a: char32 = 'a';
let b: char32 = 'b';

let eq = a == b;  // false
let lt = a < b;   // true  (U+0061 < U+0062)

Conversion

Character types are not integers, but they convert explicitly with as.

Widening to a wider char type is implicit and always safe:

let c: char32 = '★';
let wide: char64 = c;   // widening — always valid

Narrowing to a smaller char type is checked at runtime: a value that does not fit triggers a fatal error, so prefer the as? form, which returns null instead:

let wide: char32 = '🔥';              // U+1F525
let narrow = wide as char16;          // fatal error: value > U+FFFF
let safe: char16? = wide as? char16;  // null instead

Conversions to and from the backing integer type are also explicit:

let c: char32 = '★';
let n = c as uint32;      // 0x00002605
let back = n as char32;   // '★'

Integer values that are not valid Unicode scalars (surrogates U+D800–U+DFFF, or anything above U+10FFFF) cannot be converted to char32 or narrower — use as? to get null. Char types also have no arithmetic operators; cast to the integer type to compute offsets, then cast back:

let c: char32 = 'a';
let next = (c as uint32 + 1) as char32;  // 'b'

String Interop

A single character converts to a one-character String with String::From() or interpolation, and String indexing returns a char by code-point position (not byte offset):

let c: char32 = '€';
let s = String::From(c);       // "€"
let t = "{c}";                 // "€"  (interpolation)
let first: char = "Hello"[0];  // 'H'

Source files are UTF-8; in memory a char is a little-endian unsigned integer of its declared width. A single char32 is one Unicode scalar value, which is not always one visible glyph — emoji such as 👨‍👩‍👧 are several scalar values joined by zero-width joiners, so counting characters is not the same as counting glyphs.

See Also

• char — the alias keyword for this type
• char16 — the next width down
• char64 — the next width up