Specification for implementing a VM
    The stack VM works with two stacks, a base stack and a return stack.
    Memory layout
    0x0000 - SYSTEM
        00 - PC - The program counter
        01 - SP - The stack pointer. The stack is used to run operators on data.
        02 - RSP - The return stack pointer. The return stack is used to store memory addresses.
        03 - JUMP_OFFSET
        04-10 - CLI ARGS - Write arguments from the command line to these values to use them in a program
    0x0010 - IO
        10 - INPUT_LENGTH - This stores the length of input written in.
        11 - INPUT - Memory after this holds the most recent stdin.
    0c0030 - file device
      0x00 - REQUEST FS
      0x01 - PATH ADDR
      0x02 - PATH LEN
      0x03 - IN ADDR
         FORMAT
            file/path.ext;1024;type;created;modified
      0x04 - FORMAT OPTIONS - 0b0000111100001111
         1 - local path
         2 - r
         3 - w
         4 - execute
         5 - list
         6 - size
         7 - type
         8 - creation date
         9 - modified date
      0x05 - IN LEN
    ... This memory is reserved for future functionality
    0x0100 - ROM - Load the program here
    0x0600 - STACK - The stack is here in memory
    0x0700 - R_STACK - The return stack is here in memory
    ... This memory can be used to store variables and data.
    0xFFFF - END OF MEMORY

    OPERATORS
        All operators (except LIT) use postfix notation meaning the operands must be on the
        stack before the operator.
        For example to add `1` and `2` the syntax is `1 2 ADD`.
        The below operators are defined with
        `(OPERAND1 OPERAND2 OPERAND3) OPERATOR_NAME OPERATOR_BYTECODE -> (STACK STATE AFTER OPERATOR) -> 
ACTION`
.
        The parenthesis should not be included in real code.

        #define LFR 227 //LOAD FROM RETURN STACK
        #define PRS 228 //RETURN STACK PUSH
        (ADDRESS) JMR 229 -> () -> JUMP TO X. USE THE RETURN STACK
        (VALUE1 VALUE2 ADDRESS) JER 230 -> () -> JUMP TO X IF X-1 EQUAL TO X-2. USE THE RETURN STACK
        (VALUE1 VALUE2 ADDRESS) JNR 231 -> () -> JUMP TO X IF X-1 NOT EQUAL TO X-2. USE THE RETURN STACK
        NFH 232 -> (X) -> NEXT FREE HEAP
        (X MODE) CMP 233 -> (X MODE Y) -> PERFORM A COMPARISON BASED ON THE MODE
            =
            <
            >
            <=
            >=
            !=
            IS NEG
            IS POS
        () RIN 234 -> () -> READ IN FROM STDIN
        (X) LSL 235 -> (X*) -> LOGICAL SHIFT LEFT
        (X Y) AND 236 -> (X&Y) -> LOGICAL AND
        (X Y) LOR 237 -> (X|Y) -> LOGICAL OR
        (...DATA... ADDRESS LENGTH) STV 238 -> () -> STORE VARIABLE DATA AT ADDRESS X-1 OF LENGTH X
        () END 239 -> () -> End the program exiting the emulator.
        () JCC 240 -> () -> Looks at the topmost value of the return stack and jumps to that address
        (VALUE_TO_COPY) DUP 241 -> (VALUE_TO_COPY COPIED_VALUE) -> Copies VALUE_TO_COPY to the top of the 
stack
        () LIT 242 -> (NEXT_VALUE_IN_CODE) -> Declares that the next stack value is not an operator and 
places i
t onto the stack skipping execution. All non-operator operands will be prefixed with this.
        (VALUE_TO_REMOVE) POP 243 -> () -> Removes the top value from the stack, does not error on an 
empty stac
k.
        (VALUE_TO_STORE ADDRESS) STA 244 -> () -> Put VALUE_TO_STORE at ADDRESS
        (ADDRESS) LFA 245 -> (VALUE_AT_ADDRESS) -> Put the value at ADDRESS on top of the stack
        (ADDRESS) JMP 246 -> () -> Jump to ADDRESS. (Does not modify the return stack)
        (VALUE1 VALUE2 ADDRESS) JNE 247 -> () -> Jump to ADDRESS if VALUE1 != VALUE2. Put the address of 
the nex
t value on the return stack
        (VALUE1 VALUE2 ADDRESS) JEQ 248 -> () -> Jump to ADDRESS if VALUE1 == VALUE2. Put the address of 
the nex
t value on the return stack
        (VALUE1 VALUE2) SWP 249 -> (VALUE2 VALUE1) -> Swaps the positions of VALUE1 and VALUE2 on the 
stack
        (VALUE_TO_COPY ANYTHING) OVR 250 -> (VALUE_TO_COPY ANYTHING COPIED_VALUE) -> Copies VALUE_TO_COPY 
to the
 top of the stack
        (X Y) DIV 251 -> (X_DIVIDED_BY_Y) -> Does an integer divide of X by Y
        (X Y) MUL 252 -> (X_DIVIDED_BY_Y) -> Put X*Y on top of the stack
        (X Y) SUB 253 -> (X_DIVIDED_BY_Y) -> Put X-Y on top of the stack
        (X Y) ADD 254 -> (X_DIVIDED_BY_Y) -> Put X+Y on top of the stack
        (ADDRESS DATA_LENGTH DATA_FORMAT) OUT 255 -> () Output x values starting at ADDRESS to stdout 
where X eq
uals DATA_LENGTH.
        The output use DATA_FORMAT to determine how to format the data the int value of 'C' outputs as a 
charact
er the int value of 'I' outputs as an integer.

Specification for implementing a compiler
    DEFINE RULES
        ;A 1 1
            A = [1,1]
        ;B 1 1 ;C
            B = 1, C = 2
        ;D 1
            D = 1
    ;;GLOBAL_DEFINE
    ;LOCAL_DEFINE
    :DEFINE_AND_INIT_ON_RETURN_STACK VALUE

    @LABEL_MARK
    #LABEL_REFERECE

    Functions
        Definitions
            @{}NAME BODY JCC
        Calling
            { ARGS }#NAME
            ARGS NAME

    If Statements
      ?@IF_LABEL {}#load_input DUP 0 > OVR 10 < ?
         POP
      |@ELSEIF_LABEL {}#load_input DUP 10 > OVR 20 < ?
         POP
      |@ELSE_LABEL 1 ?
         POP
      ??

    Imports
        $path/to/import.ual

    Strings
        'STRING\n'
        Strings auto include null "terminators".