Javascript Execution Engine in Rust

Very simple JS Engine with basic expressions support:

1. Binary expressions like 1+(3+5)*3*(3+10)
2. Variables and changing variables:

let x = 10;
let b = 30 + 1;
b = b + 5;
x + b // evaluates to JSNumber { value: 46 }

3. Strings

let x = "Hello World"
x //  evaluates to JSString  { value: "Hello World" }

4. Block scoping

// its own scope
{
  let x = 1;
}

5. Functions

function x(a, b) { 
  return a + b;
}

x(2, 3); // evaluates to 5

6. Objects

let obj = {a: 3, b: "Hello World"}; // evaluates to JSObject { value: HashMap /w "a" - 3 as JSNumber and "b" - "Hello World" as JSString }