Troubleshooting

error.NoLanguage from parse

Call setLanguage first. It also validates the ABI — IncompatibleAbiVersion means the tables target an ABI outside 13–15.

Tree has errors on input I expected to parse

• Print the tree (examples/tree_walk.zig pattern) and look for ERROR / MISSING nodes.
• Check token coverage: characters no matcher accepts become skipped error bytes.
• Check table coverage: the grammar tables must define an action for every reachable (state, token) pair.

Query compiles but matches nothing

• Top-level patterns match anywhere, but nested patterns need direct children — (program (number)) fails when a number is nested deeper.
• Anonymous tokens match only non-named nodes; (+) never matches an identifier.
• Field names must come from the language's field map for that production.

Query compile errors

• UnexpectedToken usually means unbalanced parentheses or a stray ! assertion.
• InvalidPredicate means the #name? is unknown — see the supported list.
• An empty query source is UnexpectedEof, not an empty query.

Changed ranges are empty after an edit

Same-span text substitutions (e.g. 2 → 3) change no positions or structure, so there is structurally nothing to report. Insertions, deletions, and span changes report normally.

Leaks reported by the testing allocator

Every owning object needs deinit: parser, trees, cursors, queries, query cursors, and changed-range slices. Nodes never need cleanup.

Still stuck?

• Enable parser.setLogger(.{ .level = .debug }) and re-run.
• Open an issue at the repository with the source, the grammar tables version, and the tree dump.