Module `QCheck2.Print`

Printing functions and helpers, used to print generated values on test failures.

type 'a t = 'a -> string: Printer for values of type 'a.

val unit : unit t

unit is a printer of unit.

since: 0.6

val int : int t: int is a printer of integer.

val bool : bool t: bool is a printer of boolean.

val float : float t: float is a printer of float.

val char : char t: char is a printer of character.

val string : string t: string is a printer of string.

val option : 'a t -> 'a option t: option p is a printer of 'a option, using p if it is a Some.

val pair : 'a t -> 'b t -> ('a * 'b) t: pair p1 p2 is a printer of pair.

val triple : 'a t -> 'b t -> 'c t -> ('a * 'b * 'c) t: triple p1 p2 p3 is a printer of triple.

val quad : 'a t -> 'b t -> 'c t -> 'd t -> ('a * 'b * 'c * 'd) t: quad p1 p2 p3 p4 is a printer of quadruple.

val list : 'a t -> 'a list t: list p is a printer of list, using p for each element.

val array : 'a t -> 'a array t: array p is a printer of array, using p for each element.

val contramap : ('b -> 'a) -> 'a t -> 'b t

contramap f p transforms printer p into another using f.

Note the reverse order of types in f which may be conter-intuitive: indeed a function that prints values of type 'b can be obtained by transforming a value of type 'b to 'a using f, and then by printing this value of type 'a using p.

val comap : ('b -> 'a) -> 'a t -> 'b t

deprecated: use contramap instead.