From: Leonardo Laguna Ruiz <modlfo@gmail.com>
To: "caml-list@inria.fr" <caml-list@inria.fr>
Subject: [Caml-list] Pattern matching of records
Date: Wed, 16 Sep 2015 14:19:42 +0200 [thread overview]
Message-ID: <55F95E5E.6000209@gmail.com> (raw)
I have the following type
(* File: S.ml *)
module S = struct
type s =
{
a : int;
b : int;
}
end
I I have found that for creating records I can do as follows:
(* File: main.ml *)
open S
let s0 = S.{ a = 0; b = 0}
However this does not work for pattern matching:
(* this does not work *)
match s0 with
| S.{ a = 0 ; b = 0 } -> true
| _ -> false
These two alternatives work, but one with a warning and the other
(depending on the type) is too verbose:
(* this produces a warning *)
match s0 with
| { a = 0 ; b = 0 } -> true
| _ -> false
(* this works *)
match s0 with
| { S.a = 0 ; S.b = 0 } -> true
| _ -> false
Is there any other way of writing pattern matches as compact as S.{ a =
0 ; b = 0 } ? (which is consistent to the construction of the same value)
I know that it's possible to do:
let open S in
match s0 with
| { a = 0 ; b = 0 } -> true
| _ -> false
but the main reason I don't do it is because I have more records like:
match s0,k0 with
| { S.a = 0 }, {K.a = 0 } -> true
Best regards,
Leonardo
next reply other threads:[~2015-09-16 12:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-16 12:19 Leonardo Laguna Ruiz [this message]
2015-09-16 12:26 ` Nicolas Ojeda Bar
2015-09-16 12:26 ` Thibault Suzanne
2015-09-16 12:28 ` Leonardo Laguna Ruiz
2015-09-16 19:03 ` Gerd Stolpmann
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