Previously, Grackle could compile a single computed property like `array[x]`. But it couldn't handle:
- Nested properties like `array[x][y]`
- Nested objects like `obj[x][y]`
- Arrays nested in objects, like `{x: [1,2,3]}`
- Objects in arrays like `[{a: 1}]`
It was quite difficult to find a way to handle this, which is why I started the EP Debugger project. The debugger helped me understand the VM much better and figure out a better way to handle these cases (the two new instructions AddrOfMember and CopyLen). Now Grackle can compile those cases!
