LambdaProlog built-in data types

val int : int CData.cdata
val is_int : CData.t -> bool
val to_int : CData.t -> int
val of_int : int -> term
val float : float CData.cdata
val is_float : CData.t -> bool
val to_float : CData.t -> float
val of_float : float -> term
val string : string CData.cdata
val is_string : CData.t -> bool
val to_string : CData.t -> string
val of_string : string -> term