Positions
Coordinates
- Byte offset (
u32): index into UTF-8 source. The only coordinate everything else derives from. 32-bit by design (see x86-64). - Point (
row: u32,column: u32): zero-based line plus byte-column. Columns count bytes, so wide characters occupy multiple columns — identical to the reference runtime's convention. - Range: both systems together, with containment/overlap helpers.
Translation through edits
translateByte: before-start untouched; at/after old-end shifted by the length delta; inside clamped into the new span. translatePoint: rows before the start untouched; rows after the old end shifted; edited rows rebase columns onto the new end. Zero-width nodes at an insertion point stay at the point; content at the point shifts right.