This module provides combinators to build printers for user-defined types. It doesn't try to do pretty-printing (see for instance Pprint for this), but a simple way to print complicated values without writing a lot of code.
Those combinators work with "%a". For instance to print a (int * bool) list list and a float array, one can write:
CCPrint.(printf "int: %d list: %a, array: %a\n"
42
(list (list (pair int bool))) [[1, true; 2, false]; [4, true]]
(array float) [| 1. ; 2. ; 3e18 |] ;;Remember that "%a" in this context requires two arguments:
'a t (buffer printer)'a (value to print)To define new printers, one can either use existing ones (e.g. list int), or use Printf.bprintf. For instance a printer for colored points in 2D:
type point = {x:int; y:int; colors: string list};;
let pp_point buf p =
Printf.bprintf buf "{x=%d, y=%d, colors=%a}"
p.x p.y CCPrint.(list string) p.colors;;type 'a t = Buffer.t -> 'a -> unitA printer for the type 'a
val silent : 'a tprints nothing
val unit : unit tval int : int tval string : string tval bool : bool tval float3 : float tval float : float tval char : char tval output : Pervasives.out_channel -> 'a t -> 'a -> unitval to_string : 'a t -> 'a -> stringval sprintf : ('a, Buffer.t, unit, string) Pervasives.format4 -> 'aPrint into a string
val fprintf :
Pervasives.out_channel ->
('a, Buffer.t, unit, unit) Pervasives.format4 ->
'aPrint on a channel
val to_file : string -> ('a, Buffer.t, unit, unit) Pervasives.format4 -> 'aPrint to the given file
val printf : ('a, Buffer.t, unit, unit) Pervasives.format4 -> 'aval eprintf : ('a, Buffer.t, unit, unit) Pervasives.format4 -> 'amodule type MONAD_IO = sig ... end