Facet project aims to reduce Rust compilation times via reflection
Key Takeaway
The facet project uses type reflection to avoid the heavy monomorphization costs associated with Serde in Rust.
Summary
Developer 'Faster Than Lime' has introduced facet, a new Rust project designed to optimize serialization performance and build speeds. Unlike Serde, which relies on heavy generic instantiation, facet uses a 'SHAPE' associated constant to provide type information at runtime. This approach allows for format crates like facet-json and facet-yaml to operate without generics, potentially significantly reducing compilation times.
Technical approach of facet
- Uses an associated constant called SHAPE to describe type structures (enums, structs, etc.).
- Provides vtables for collections like lists, maps, and sets.
- Includes metadata for fields, including offsets and their own shapes.
- Implements Peek for serialization and reflection-based value construction.
- Aims to eliminate the need for generics in format-specific crates (e.g., facet-json, facet-yaml) to speed up builds.
Why it matters
If successful, facet could provide a faster alternative to Serde for large-scale Rust projects where compilation overhead is a bottleneck.
Original reference: fasterthanli.me →