Show HN: Inception: Automatic Rust Trait Implementation by Induction
4 days ago
- #Structural Induction
- #Rust
- #Macros
- The text discusses the concept of structural or well-founded induction, introduced by Dmitry Mirimanoff in 1917, and its application in Rust programming.
- It presents a method to automatically implement traits like `Blockbuster` for complex types composed of simpler elements that already satisfy the trait, without manual implementation.
- The approach involves using a custom derive macro (`Inception`) to expose a type's fields as a type-level list, enabling recursive trait implementation based on the properties of its substructures.
- An example is provided with `LeonardoDiCaprio` and `CillianMurphy` as base cases for the `Blockbuster` trait, showing how composite types like `Inception1` can automatically inherit the trait.
- The text acknowledges limitations and challenges, such as the inefficiency of handling enum variant fields and the unconventional use of Rust's trait system, suggesting the approach is more of a proof-of-concept than a practical solution.
- The author reflects on the novelty and limitations of the approach, expressing skepticism about its widespread adoption but leaving the door open for further exploration by the community or AI tools.