Lisp
type t =
| Int of int
| Str of string
| Sym of string
| Cons of t * t
| Subr of string
val nil : t
val t : t
val of_bool : bool -> t
val truthy : t -> bool
val list : t list -> t
val to_list : t -> t list option
val print : t -> string
val princ : t -> string