Import with #import "std/unicode".
CaseFold :: (text: string) -> TextFull default (non-Turkic) case folding, including multi-scalar expansions.
Lower :: (text: string) -> TextFull default lowercase, including the contextual Greek final sigma rule.
LowerInto :: (text: string, output: *Vec(u8)) -> boolReplace caller-owned output with full default lowercase, including final sigma. Unlike Lower, reject malformed UTF-8. Input must not borrow output. Empty input succeeds; every failure empties output (capacity may remain).
NFCInto :: (text: string, output: *Vec(u8)) -> boolCanonical Unicode normalization; same ownership/failure contract as LowerInto. No compatibility decomposition or locale tailoring.
IsLetter :: (point: u32) -> boolExact General_Category L and N aggregates, and Unicode White_Space. White_Space excludes Python IsSpace's extra U+001C..U+001F controls.
IsNumber :: (point: u32) -> boolIsWhiteSpace :: (point: u32) -> boolCapitalize :: (text: string) -> TextPython str.capitalize: titlecase the first scalar, lowercase the remainder.
IsWord :: (codepoint: u32) -> boolPython Unicode regex \w: letters, numeric characters, and underscore.
IsDecimal :: (codepoint: u32) -> boolPython Unicode regex \d: decimal digits, General_Category Nd only.
IsPrintable :: (codepoint: u32) -> boolPython-style printability at Unicode 17.0: L/M/N/P/S categories and ASCII space. All other separators, controls, formats, private-use and unassigned characters are excluded. This describes text, not font glyph availability.
IsSpace :: (codepoint: u32) -> boolPython str.isspace / regex \s, including U+001C..U+001F.
IsWhitespace :: (text: string) -> boolPython str.isspace: empty text is false. Invalid UTF-8 is not whitespace.
SplitWhitespace :: (text: string) -> Vec(string)Python str.split() without a separator: collapse whitespace runs and omit empty pieces. Returned pieces borrow text; keep its storage alive.