Module highlight 

Marking ranges of text that somebody else owns.

The boundary, and what the caller owes

This crate does not search text. Deciding that a run of characters answers a query is the same kind of judgement as deciding that a word is a keyword: it needs to know about case folding, word boundaries, normalisation forms, whether the query is a regular expression, and what the host considers one document — none of which a product-neutral component can answer, and all of which the application that owns the text already has.

So the component takes ranges, not a query. The caller owes:

1. the exact SharedString it wants marked, handed to this component;
2. byte offsets into that string, on character boundaries;
3. ranges sorted ascending and not overlapping one another;
4. which of them, by index, is the current one — or none.

A range that breaks any of those is skipped rather than drawn wrongly and rather than panicking, because a highlight is decoration over text that is still readable without it: losing a mark is recoverable, losing the line is not. HighlightedText::published_hits reports how many were actually drawn, so a caller that got the offsets wrong can see it.

The same boundary serves the read-only code view, which takes pre-classified CodeSpans for exactly the same reason.

Structs

HighlightedText

A run of text with some of it marked.