A compiler written in Rust for the Lox programming language.

Implementation of clox (bytecode) in Robert Nystrom's Crafting Interpreters book.

I am writing it while learning Rust, so it is definitely not perfect/idiomatic.

Run by cargo run. Run with debug mode by cargo run --all-features.

Test with cargo test -- --nocapture (--nocapture means print statements will be shown).

Difference between rust-lox and clox

• Op instruction is implemented with the OpCode enum (instead of u8), which could be > 1 byte. A chunk has a Vec of OpCode.
  • Different offset calculation
  • Instead of reading 2 bytes, OpCode::Constant, OpCode::GetGlobal and OpCode::DefineGlobal includes a u8 as the extra byte
• Use usize index instead of pointer+dereference to access element in array.
  • Though pointer+dereference should be faster?
• Tagged union replaced by Enum(T)
• No Value::Obj that can save arbitary object
• String Object (Value::StringObj(u32)) is interned by HashMap<String, u32>
• No printing for Function object
• Pointer operations are replaced by index lookup
• Following the same code structure of clox will mess up ownership in rust, so there are many tweaks about that (e.g. compiler.enclosing, mutable and immutable ref to self.frame in vm.rs, etc.)
• Save Function to a list in VM, while the Value stores the index

TODO

• Garbage Collection
• Classes and Instances
• Optimization