exa_grammar.ohm

EXAScript {

    Program = Instruction*

    Instruction = CopyInstr
                    | AddInstr
                    | SwizInstr
                    | MarkInstr
                    | JumpInstr
                    | TJumpInstr
                    | FJumpInstr
                    | TestInstr
                    | ReplInstr
                    | HaltInstr
                    | KillInstr
                    | LinkInstr
                    | HostInstr
                    | ModeInstr
                    | VoidInstr
                    | MakeInstr
                    | GrabInstr
                    | FileInstr
                    | SeekInstr
                    | DropInstr
                    | WipeInstr
                    | NoopInstr
                    | noteInstr
                    | RandInstr
                    | AddInstruction
                    | SubtractInstruction
                    | MultiplyInstruction
                    | DivideInstruction
                    | LoopMacro

    Register = GeneralRegister
             | TestRegister
             | FileRegister
             | MessageRegister
             | HardwareRegister

    EXANumber = "-" digit4 -- negative
           |     digit4 -- positive

    // there must be a better way to do this
    digit4 = digit digit? digit? digit? space?

    GeneralRegister = "X"
    TestRegister = "T"
    FileRegister = "F"
    MessageRegister = "M"
    HardwareRegister = "#" validString



    Parameter = Register | EXANumber
    label = validString //alnum+ newline
    newline = "\n"
    TestSubChars = "<" | "=" | ">"
    onlySpace = " " // todo make a more elegant solution to this
    validString = onlySpace? (alnum | "_")* newline?
    // apparently in ohm space is any whitespace not " " so i got messed up real bad
	validNoteString = onlySpace? (alnum | "_" | onlySpace)*
    
    CopyInstr = "COPY" Parameter Register // works
    AddInstr = "ADDI" Parameter Parameter Parameter
    SwizInstr = "SWIZ" Parameter Parameter Register
    
    MarkInstr = "MARK" label
    JumpInstr = "JUMP" label
    TJumpInstr = "TJMP" label
    FJumpInstr = "FJMP" label

    TestInstr = "TEST" Parameter TestSubChars Parameter -- value
              | "TEST" "MRD" -- comm
              | "TEST" "EOF" -- file
	
    // Interaction with other EXAs
    ReplInstr = "REPL" label
    HaltInstr = "HALT"
    KillInstr = "KILL"
	
    // Exa Movement and Host Inters
    LinkInstr = "LINK" Parameter
    HostInstr = "HOST" Register
	
    // EXA State Instructions
    ModeInstr = "MODE"
    VoidInstr = "VOID" MessageRegister
              | "VOID" FileRegister
	
    // File Instructions
    MakeInstr = "MAKE"
    GrabInstr = "GRAB" Parameter
    FileInstr = "FILE" Register
    SeekInstr = "SEEK" Parameter
    DropInstr = "DROP"
    WipeInstr = "WIPE"
	
    // Auxilary Instructions
    NoopInstr = "NOOP"
    noteInstr = "NOTE" validNoteString
    RandInstr = "RAND" Parameter Parameter Register
	
    // Arithmetic
    AddInstruction = "ADDI" Parameter Parameter Register
    SubtractInstruction = "SUBI" Parameter Parameter Register
    MultiplyInstruction = "MULI"  Parameter Parameter Register
    DivideInstruction = "DIVI" Parameter Parameter Register
    
    LoopMacro = "@REP" digit Instruction* "@END"

}