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| author |  Hugo Herbelin <Hugo.Herbelin@inria.fr> | 2017-08-21 23:49:20 +0200 |
|---|---|---|
| committer | Hugo Herbelin <Hugo.Herbelin@inria.fr> | 2017-09-12 20:17:27 +0200 |
| commit | 8b07b9296dac108d7a3d44db227bb1c6042db555 (patch) | |
| tree | 63a788b3e9fc6c4094b86417058f06f630b3bc01 | |
| parent | cc94172036789cfef28007f59510b7f17df5d45d (diff) | |
Adding function to be typically used to pass values from an OCaml "when" clause.
| -rw-r--r-- | lib/util.ml | 9 | ||||
| -rw-r--r-- | lib/util.mli | 5 |
2 files changed, 14 insertions, 0 deletions
diff --git a/lib/util.ml b/lib/util.ml index 36282b2da..6de012da0 100644 --- a/lib/util.ml +++ b/lib/util.ml @@ -171,3 +171,12 @@ let open_utf8_file_in fname = let s = Bytes.make 3 ' ' in if input in_chan s 0 3 < 3 || not (is_bom s) then seek_in in_chan 0; in_chan + +(** A trick which can typically be used to store on the fly the + computation of values in the "when" clause of a "match" then + retrieve the evaluated result in the r.h.s of the clause *) + +let set_temporary_memory () = + let a = ref None in + (fun x -> assert (!a = None); a := Some x; x), + (fun () -> match !a with Some x -> x | None -> assert false) diff --git a/lib/util.mli b/lib/util.mli index d910e7e28..c54f5825c 100644 --- a/lib/util.mli +++ b/lib/util.mli @@ -137,3 +137,8 @@ val sym : ('a, 'b) eq -> ('b, 'a) eq val open_utf8_file_in : string -> in_channel (** Open an utf-8 encoded file and skip the byte-order mark if any. *) + +val set_temporary_memory : unit -> ('a -> 'a) * (unit -> 'a) +(** A trick which can typically be used to store on the fly the + computation of values in the "when" clause of a "match" then + retrieve the evaluated result in the r.h.s of the clause *) |