type arithmetic_command =
  | Add
  | Sub
  | Neg
  | Eq
  | Gt
  | Lt
  | And
  | Or
  | Not

type memory_segment =
  | Argument
  | Local
  | Static
  | Constant
  | This
  | That
  | Pointer
  | Temp

type memory_command =
  | Push
  | Pop

type branching_command =
  | Label
  | Goto
  | Ifgoto

type function_command =
  | Function
  | Call

type expr =
  | Comment of string
  | ArithmeticCommand of arithmetic_command
  | MemoryAccessCommand of memory_command * memory_segment * int
  | ProgramFlowCommand of branching_command * string
  | FunctionCallCommand of function_command * string * int
  | Return