proto-blue-codegen

Code generator that produces Rust types from AT Protocol Lexicon JSON schemas.

This is a binary crate, not a library.

Installation

cargo install proto-blue-codegen

Usage

proto-blue-codegen --lexicons path/to/lexicons --output path/to/output

The generator reads Lexicon JSON schema files from the input directory and writes Rust source files to the output directory. The generated types include records, queries, procedures, and subscriptions defined by the AT Protocol.

Output format

• String fields with a recognised format (did, handle, at-identifier, nsid, at-uri, tid, record-key, datetime) emit as the corresponding validated newtype from proto_blue_syntax rather than String. XRPC param helpers (to_query_params, params_from_ctx) round-trip through Display::to_string and <Newtype>::new(&str)?.
• Inline unions in property position emit a synthesised sum-type enum named <TypeName><PropertyPascalCase>Refs (or …ItemRefs for Array<Union>), replacing the previous serde_json::Value fallback.
• Reserved-keyword sanitization covers Rust 2024 edition keywords (gen, try), reserved-for-future words (abstract, become, box, do, final, macro, override, priv, typeof, unsized, virtual, yield), and union / dyn.
• Sibling-name collisions after sanitization are disambiguated with _2/_3/... suffixes and a doc comment recording the collision, instead of silently emitting invalid Rust.
• An NSID that is both a leaf and a parent (e.g. com.example.foo and com.example.foo.bar) writes leaf content into <path>/mod.rs with the child pub mod declarations appended, fixing a previous E0761 ambiguous-module-file error.
• NSID segments containing dashes emit #[path = "<orig>/mod.rs"] pub mod <snake>; so the on-disk path and the Rust identifier agree.
• Multi-line lexicon descriptions get /// continuation per line.

Tests

The crate ships two opt-in tests for catching second-order regressions against a real-world Lexicon corpus. Drop a checkout of the wider ecosystem's lexicons into lexicons.wild/ at the workspace root to enable them:

• generate_types_from_wild_corpus runs the codegen against the corpus and asserts no panics plus structural sanity.
• wild_corpus_compiles (#[ignore] by default) synthesises a side workspace crate from the generated output and runs cargo build against it, catching errors that only surface at rustc time.

License

Licensed under MIT OR Apache-2.0.

Part of the proto-blue AT Protocol SDK for Rust.