Query Captures

What you'll learn

• How @name captures attach to pattern nodes and how to read them from matches.

Complete example

var query = try parser.compileQuery("(term left: (_) @l right: (_) @r)");
defer query.deinit();
// ... execute ...
const m = cursor.nextMatch().?;
// m.pattern_index, m.captures[0].name, m.captures[0].node

A Match carries its pattern_index (which top-level pattern matched) and a slice of Capture values, each with the capture name, its name_index, and the matched Node.

How it works

Capture names are interned once at compile time (captureIndexForName / captureName). During matching, every pattern node with a capture records (name, node) into the matcher's scratch list; on success the slice is duplicated into the cursor's match storage, so matches stay valid while the cursor lives even as matching continues.

API used

• Query — captureCount, captureName, captureIndexForName; Query Cursor — nextMatch, matchCount.

Related guides

• Queries, Query Cursors