7. Recognition Mode (3F7e9bf)

• RecognizeOnly (pego parse -check) runs a separate program derived from the same grammar that builds no values and runs no actions, and returns the same syntax errors. Rules whose values predicates read still run normally.
• Effect: 1.5–1.8× faster than a full parse (JSON 78 → 44 ms). Compare it with json.Valid, not with parsers that build trees.