How do I debug a grammar?

[verhovsky]

I want to know what course the parser took through a given input and why it applied a given rule at a given position. How do I do that?

[sogaiu]

I don't know about figuring out the precise rule, but the --debug and --debug-graph (this one makes a log.html file with svg in it) flags of the parse subcommand for the tree-sitter cli gives some detailed info about parsing.

I have some introductory notes on these bits here and here. Not sure how much help those will be but FWIW.

There's also a --report-states-for-rule option for the generate subcommand, but I'm not sure what it does in detail.