Text bound

# A length bound on text names its unit (decided 2026-09-22): text has three lengths.
fn greet [lent 'name': str.utf8[min 1, max 10 graphemes]] { std::print.useful["hi ", 'name', newln]; }

MAIN {
    let 'thai': str.utf8[min 1, max 10 graphemes] = "เกี่ยว";       # 4 graphemes (เ|กี่|ย|ว), 6 points, 18 bytes: fits
    let 'ascii': str.utf8[min 0, max 5 bytes] = "hello";            # 5 bytes: fits
    greet[lend 'thai'];
    greet[lend 'ascii'];
    let mut 'line': str.utf8[min 0, max 20 bytes] = str.empty;
    change 'line' = 'line' ++ "twelve chars";                      # 12 bytes: fits
    std::print.useful[str.bytes[lend 'line'], newln];
    let 'short' := to.stored.str.utf8[min 0, max 3 bytes][12345] otherwise "?";     # into a bounded text: fails out_of_range
    std::print.useful['short', newln];
}