Compound assignment for arrays is working, untested, read more

I added reference values in 62ca7a1fb7,
but forgot to mention it. I'm now using references to assign to the
internals of an array, no matter how many levels deep it is.

source/toy_opcodes.h

@@ -1,12 +1,15 @@
 #pragma once
 
 typedef enum Toy_OpcodeType {
+	//This offsets the opcode values, so I can see TOY_OPCODE_READ in GDB clearly
+	TOY_OPCODE_UNUSED = 0,
+
 	//variable instructions
 	TOY_OPCODE_READ,
 	TOY_OPCODE_DECLARE,
 	TOY_OPCODE_ASSIGN,
+	TOY_OPCODE_ASSIGN_COMPOUND, //assign to a compound's internals
 	TOY_OPCODE_ACCESS,
-
 	TOY_OPCODE_DUPLICATE, //duplicate the top of the stack
 
 	//arithmetic instructions