open Types

type calling_conv =
  | Boxed
  | Unboxed

type repr =
  | RInt
  | RBool
  | RBox of typ
  | RTuple of repr list
  | RSum of repr * repr
  | RFun of calling_conv * repr list * repr

type var = string

type term =
  | Var of var
  | Int of int
  | Bool of bool
  | Tuple of term list
  | Proj of int * term
  | Inl of repr * repr * term
  | Inr of repr * repr * term
  | Case of term * (var * term) * (var * term)
  | Lam of calling_conv * (var * repr) list * repr * term
  | App of term * term list
  | Let of var * term * term
  | LetRec of var * repr * term * term
  | EqInt of term * term
  | EqBool of term * term
  | If of term * term * term
  | Box of typ * term
  | Unbox of term
  | Roll of typ * term
  | Unroll of term
  | WorkerWrapper of worker_wrapper
  | Halt of term

and worker_wrapper = {
  wrapper : var;
  worker : var;
  boxed_arg : typ;
  unboxed_args : repr list;
  result_repr : repr;
  wrap_body : term;
  worker_body : term;
  in_term : term;
}

type value =
  | VInt of int
  | VBool of bool
  | VTuple of value list
  | VInl of repr * repr * value
  | VInr of repr * repr * value
  | VLam of calling_conv * (var * repr) list * repr * term
  | VBox of typ * value
  | VRoll of typ * term

type outcome =
  | Value of value
  | Stuck of string
  | Diverged of int

type trace = {
  steps : term list;
  outcome : outcome;
}

val string_of_repr : repr -> string
val string_of_term : term -> string
val string_of_value : value -> string
val is_value : term -> bool
val step : term -> (term, string) result
val evaluate : ?fuel:int -> term -> trace
val observe : ?fuel:int -> term -> outcome