There's no interpreter, I just map each instruction to equivalent Rust code. Linear memory is accessed through a trait.

The compiler is here: https://github.com/CryZe/wasm-to-rust

I have an example of a GameBoy emulator compiled from AssemblyScript to WASM to Rust here: https://github.com/CryZe/wasmboy-rs/blob/master/src/wasm.rs