Struct BidiRun 

pub struct BidiRun {
    pub byte_range: Range<usize>,
    pub direction: TextDirection,
    pub visual_order: usize,
    pub level: u8,
}

A bidi run: a contiguous range of text with the same direction.

Fields

byte_range: Range<usize>

direction: TextDirection

visual_order: usize

Visual order index (for reordering after line breaking).

level: u8

UAX #9 embedding level: even is LTR, odd is RTL.

Rule L2 reorders by level, not by direction, and the two are not interchangeable: a Latin phrase quoted inside Arabic inside an English paragraph sits at level 2, and reordering it as though it were level 0 puts it on the wrong side of the Arabic. direction cannot tell those apart — level can.