A practical introduction to parsing in Rust
20 hours ago
- #Rust
- #parsing
- #compiler
- Parsing transforms text into computer instructions, with parsers being a key stage in compilers.
- Parsers convert source code into syntax trees, which can be concrete (CST) or abstract (AST).
- The article introduces a simple language called 'simp' for parsing demonstration, inspired by Rust.
- Lexical analysis (lexing) splits source text into tokens, simplifying parsing by matching tokens instead of characters.
- The 'Logos' library is used for efficient lexer generation, handling tokens like keywords, operators, and literals.
- Parsing involves recursive descent, following grammar rules to build syntax trees from tokens.
- The parser handles statements (functions, variables) and expressions (arithmetic, calls) with precedence and associativity.
- Error recovery and reporting are crucial for user-friendly parsing, suggesting multiple error reports per file.
- Performance optimizations include arena allocation and minimizing small allocations in AST representation.
- Testing parsers effectively involves snapshot testing for ASTs and error messages, using tools like 'insta' and 'glob_test'.