[Libguestfs] [PATCH 1/4] mllib: Add Common_utils 'may' function.

This higher order function encapsulates the following pattern: match x with | None -> () | Some x -> f x (replaced with: `may f x`) This is taken from OCaml lablgtk (Gtk bindings) where this pattern is used frequently. See also: https://ocaml.org/learn/tutorials/labels.html --- mllib/common_utils.ml | 4 ++++ mllib/common_utils.mli | 3 +++ 2 files changed, 7 insertions(+) diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml index d654fa8..52079d2 100644 --- a/mllib/common_utils.ml +++ b/mllib/common_utils.ml @@ -267,6 +267,10 @@ let rec assoc ?(cmp = compare) ~default x = function | (y, y') :: _ when cmp x y = 0 -> y' | _ :: ys -> assoc ~cmp ~default x ys +let may f = function + | None -> () + | Some x -> f x + let istty chan = Unix.isatty (Unix.descr_of_out_channel chan) diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli index 6e08e43..d8f63d5 100644 --- a/mllib/common_utils.mli +++ b/mllib/common_utils.mli @@ -124,6 +124,9 @@ val assoc : ?cmp:('a -> 'a -> int) -> default:'b -> 'a -> ('a * 'b) list -> 'b (** Like {!List.assoc} but with a user-defined comparison function, and instead of raising [Not_found], it returns the [~default] value. *) +val may : ('a -> unit) -> 'a option -> unit +(** [may f (Some x)] runs [f x]. [may f None] does nothing. *) + val prog : string (** The program name (derived from {!Sys.executable_name}). *) -- 2.5.0