dtolnay/syn

Health v2 · maintenance only

Adoption not part of the score

3415 stars · 373 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Syn is a Rust parsing library that converts a stream of Rust tokens into a syntax tree of Rust source code. It is primarily designed for use in Rust procedural macros, providing syntax tree data structures, parsing APIs, and span-based error reporting.

Use cases

• parse rust source code into a syntax tree
• write a rust procedural macro
• build a custom derive macro
• generate compiler-style error messages with token spans
• parse custom DSL syntax in rust

When to choose

• you are building Rust procedural macros (derive, attribute, or function-like)
• you need a full syntax tree representation of Rust code
• you want precise span information for error reporting in macros
• you need to parse custom token-stream syntaxes in Rust

When to avoid

• you need to parse languages other than Rust
• you only need lightweight token manipulation without a syntax tree
• you want to format or pretty-print Rust code rather than parse it

Facets

library · maturity stable

parser compiler developer-tools parsers programming-languages developer-tools rust cross-platform proc-macro syntax-tree rust token-parsing derive-macros

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