Module span 

Source positions/ranges anchored to UTF-16 code-unit offsets (1-based line/column). Port of varar-core/src/span.ts / Span.java.

Structs

LineCol

A 1-based line/column position.

Span

A source range [start_offset, end_offset) in UTF-16 code units, with 1-based line/column at each end.

Functions

line_col

Computes the 1-based (line, col) at offset (a UTF-16 code-unit index) into source. Walks per UTF-16 code unit from the start, exactly like Java’s charAt loop (so an astral character advances col by 2).