Returns true when a segment boundary falls between string_before and string_after.

The automaton always restarts at a boundary, so the question "is there a break at this join" is answered by segmenting from the start of the combined text and asking whether any boundary lands exactly on the join.

Returns {segment, rest}, or nil when string is empty.

Splits string using the rules alone, without the dictionary pass.

Splits string into segments.

Where the data defines dictionary symbols, the rule-based segments are passed through the dictionary breaker afterwards, which is how the standard describes complex context-dependent breaking being triggered.