evalNativeFunc :: NativeFunc -> ProgramState -> Either String ProgramState
evalNativeFunc Drop (ProgramState {dataStack = []}) = Left "error, cannot drop from empty stack"
evalNativeFunc :: NativeFunc -> ProgramState -> Either String ProgramState
evalNativeFunc Drop (ProgramState {dataStack = []}) = Left "error, cannot drop from empty stack"
evalNativeFunc Drop (ProgramState {dataStack = []}) = Left "error, cannot drop from empty stack"