Module Expr_generator.Polymorphic

type func

This phantom type represents the type of functions in our expressions. We use a phantom type here because, we do not know (or need to know) the type of the parameters or return value of functions in our expressions. We need to use a phantom type however to make sure that certain expressions such as lists or tuples are used as functions.

type _ expr =
  1. | Var : 'a expr
  2. | List : 'a expr list -> 'a list expr
  3. | Cons : 'a expr * 'a list expr -> 'a list expr
  4. | Tuple : 'a expr * 'b expr -> ('a * 'b) expr
  5. | App : func expr * 'a expr list -> 'a expr
  6. | Eq : 'a expr * 'a expr -> bool expr
  7. | Gt : 'a expr * 'a expr -> bool expr
  8. | Lt : 'a expr * 'a expr -> bool expr
  9. | Or : bool expr * bool expr -> bool expr
  10. | And : bool expr * bool expr -> bool expr
  11. | Not : bool expr -> bool expr
  12. | If : bool expr * 'a expr * 'a expr -> 'a expr

This GADT represents Ocaml expressions

type polyVal

This phantom type represents expressions that have a completely polymorphic type. For example x or if a then b else c would have a completely polymorphic type, however [x] or (a, b) would not.

type _ typ =
  1. | AT : polyVal typ
  2. | ListT : 'a typ -> 'a list typ
  3. | TupleT : 'a typ * 'b typ -> ('a * 'b) typ
  4. | FuncT : func typ
  5. | BoolT : bool typ

This GADT represents the types of expressions

val gen_string : int -> string

Generates the string representation of an expression with the given depth.

val generate : 'a typ -> int -> 'a expr

Generates a random expression.

  • parameter typ

    the typ of the expression that will be generated

  • parameter depth

    the depth of the expression that will be generated.

val to_string : 'a expr -> string

Converts an expression to a string.