tree-sitter-cairo

An attempt at parsing Cairo's code (written in Rust) with tree-sitter, to produce a grammar.js for Cairo.

WARNING: This project is not working yet, due to some ambiguities in the grammar file.

How to use

Make sure you have tree-sitter, nodejs installed.

cd cairo-syntax-parser/
cargo run > ../grammar.js
cd ../
tree-sitter generate

Overview of the project's logic

1. The whole syntax for Cairo is defined here.

2. There is also a lexer there,

3. And more files related to operators precedence in the same project.

As Cairo is defined with some Rust code, the idea is to programmatically parse some Rust using tree-sitter, in order to output a working grammar.js for Cairo.

This code first parses lexer.rs and operators.rs, then parses cairo_spec.rs and generate the grammar.

Parsing lexer.rs

This is done by: cairo_syntax_parser/lexer_file_parser.rs.

It tries its best to automatically generate JS code from the lexer.rs file. In some cases, some hand-made JS code is written instead.

This module has a main handle parse_lexer(file: &str) which returns two hashmaps for later use.

Parsing operators.rs

This is done by: cairo_syntax_parser/operators_parser.rs.

It produces two hashmaps unary_precedence, post_precedence, both of type HashMap<u32, Vec<String>>. Each maps one level of precedence k to a list of those operators who have precedence equal to k.

This module has a main handle parse_operators(file: &str) which returns two hashmaps for later use.

Parsing cairo_spec.rs

This is done by cairo_syntax_parser/cairo_spec_parser.rs.

There is first a preprocessing phase to handle add_option method calls, and to remove structs that would match the empty string. Then the grammar is generated with a call to iterate_nodes_aggregator, which uses the hashmaps from before.

This module has a main handle parse_cairo_spec(...) which returns a single String containing all the grammar rules.