Logging

What you'll learn

• How to enable level-gated logging and record parse events.

Complete example

parser.setLogger(.{ .level = .debug, .prefix = "my-parser" });
// ... parse ...
parser.setLogger(.{}); // back to silent (.off is the default)

Levels, in increasing verbosity: .off, .err, .warn, .info, .debug, .trace. Disabled levels compile to a cheap integer comparison — no formatting work happens when logging is off.

For programmatic tracing, attach a Tracer (caller-owned) alongside the logger — the parser records structured TraceEvents (parse_begin, shift, reduce, accept, recover, lex_token, reuse_node) into it:

var tracer = treesitter.Tracer.init(gpa, .{ .level = .off });
defer tracer.deinit();
parser.setTracer(&tracer);
// ... parse ...
std.debug.print("events: {d}\n", .{tracer.count()});
parser.setTracer(null); // detach

API used

• Logging; debug/logger.zig and debug/trace.zig via treesitter.debug_mod.

Related guides

• Debugging example, Troubleshooting