RUst way for Reuse Analysis.

Rura is a purely functional Rust dialect, optimized through reuse analysis and more.

1. Seamless interpolation with Rust via code generation, while reusing other useful constructs like the trait system
2. Rust-native reference counting for memory management
3. Frame-limited reuse analysis, eliminating many of the allocations and other slow paths
4. Uniqueness types (new!) could boost the performance by getting rid of unnecessary refcount
5. More scalar types are available without any boxing

In Koka and Lean, reuse analysis is supported by a lightweight runtime with reference counting and type-erased objects. This project attempts to create a functional programming language that directly lowers into Rust. In this way, we can explore the possibility to embed reuse analysis into higher-level languages.

We implement the reuse analyzer based on:

1. Perceus
2. Frame-limited reuse
3. Fully in-place Function Programming

Uniqueness type and its linearity checking from:

1. Linear type can change the world

Additionally, the idea of reduce duplication and improve sharing has also been discussed in some other situations:

1. HVM
2. Optimal Sharing

1. Surface Syntax Specification (TODO)
2. Types
3. Ownership Model
4. Linearity/Exclusivity
5. Closures
6. Lowering