Debugging

What you'll learn

• Turning broken parses into actionable diagnostics.

Complete example

examples/error_recovery.zig:

for ([_][]const u8{ "1 + * 2", "(1 + 2", "1 @ 2" }) |source| {
    var tree = try parser.parseString(source);
    defer tree.deinit();
    std.debug.print("{s} => has_error={} nodes={d}\n", .{ source, tree.hasError(), tree.nodeCount() });
}

Expected output

1 + * 2 => has_error=true nodes=11
(1 + 2 => has_error=true nodes=15
1 @ 2 => has_error=true nodes=6

How it works

Each input exercises a different recovery path: a skipped operator becomes an ERROR leaf, the unclosed paren gains a zero-width MISSING ), and the illegal @ byte is skipped. Pair this with parser.setLogger(.{ .level = .debug }) to watch shifts, reductions, and recovery events while diagnosing grammar-table gaps.

API used

• Tree, Node, Errors, Logging.

Related guides

• Error Recovery, Logging, Troubleshooting