Module `Format.Args`

The Args module defines a heterogeneous list type, which can be used as the argument of printf-like functions.

It is not required to open this module when using the functions that accept an Args.t. Thanks to type-based disambiguation, the type is inferred automatically, so the list syntax [x; y; z] can be used directly for heterogeneous lists.

An example:

  (* without opening Args *)
  Format.lprintf "%s %d %.02f@." [ "ocaml"; 42; 3.14 ]

  (* or with explicit construction *)
  let lst = let open Format.Args in "ocaml" :: [ 42; 3.14 ] @ [ 'c' ] in
  Format.lprintf "%s %d %.02f %c@." lst

since 5.5

type t('a, 'r) =

| [] : t('r, 'r)
| ::('a, t('b, 'r)) : t('a => 'b, 'r)

;

let apply: 'a => t('a, 'r) => 'r;

let (@): t('a, 'r1) => t('r1, 'r2) => t('a, 'r2);