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Date: Wed, 4 Apr 2012 16:25:48 -0400
Message-ID: <CAGyUfm0SkjTVZ4hcQRNGThWWzGoXbbVnBXHBDcr1jP=6cFCMkQ@mail.gmail.com>
From: Pierre Chopin <pierre@punchup.com>
To: caml-list@inria.fr
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Subject: [Caml-list] exn vs option


--f46d04426aa49f224b04bce03a03
Content-Type: text/plain; charset=ISO-8859-1

Hi,

I benchmarked two programs, in one case the main function throw an
exception that is caught, in the other the function returns an option that
is pattern matched on.

I noticed that, whether the exception is thrown or not, the option version
is always faster.

Is there any case where it makes sense, performance wise, to use exception
instead of 'a option ?

test1.ml
----------------------------------------------------------------------

exception Foo
let f x =
 if x =1 then raise Foo else ()

;;

 for i = 0 to 10_000_000 do
try
    f 1
with Foo -> ()
done
------------------------------------------------------------------------
test2.ml:
------------------------------------------------------------------------
let f x =
    if x=1 then None else Some ()

;;
for i = 0 to 10_000_000 do
    match f 1 with
        None -> ()
    |   Some s -> s
    done
------------------------------------------------------------------------



-- 
Pierre Chopin,
Chief Technology Officer and co-founder
punchup LLC
pierre@punchup.com

--f46d04426aa49f224b04bce03a03
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div>Hi,</div><div><br></div><div>I benchmarked two programs, in one case t=
he main function throw an exception that is caught, in the other the functi=
on returns an option that is pattern matched on.</div><div><br></div><div>
I noticed that, whether the exception is thrown or not, the option version =
is always faster.</div><div><br></div><div>Is there any case where it makes=
 sense, performance wise, to use exception instead of &#39;a option ?</div>
<div><br></div><div><a href=3D"http://test1.ml">test1.ml</a></div><div>----=
------------------------------------------------------------------</div><di=
v><br></div><div><div>exception Foo</div><div>let f x =3D</div><div>=A0if x=
 =3D1 then raise Foo else ()</div>
<div><br></div><div>;;</div><div><br></div><div>=A0for i =3D 0 to 10_000_00=
0 do</div><div>try</div><div>=A0 =A0 f 1</div><div>with Foo -&gt; ()</div><=
div>done</div></div><div>--------------------------------------------------=
----------------------</div>
<div><a href=3D"http://test2.ml">test2.ml</a>:</div><div><div><div>--------=
----------------------------------------------------------------</div></div=
><div>let f x =3D</div><div>=A0 =A0 if x=3D1 then None else Some ()</div><d=
iv><br>
</div><div>;;</div><div>for i =3D 0 to 10_000_000 do</div><div>=A0 =A0 matc=
h f 1 with</div><div>=A0 =A0 =A0 =A0 None -&gt; ()</div><div>=A0 =A0 | =A0 =
Some s -&gt; s</div><div>=A0 =A0 done</div></div><div><div>----------------=
--------------------------------------------------------</div>
</div><div><div><br></div></div><div><br></div><div><br></div>-- <br>Pierre=
 Chopin,<div>Chief Technology Officer and co-founder</div><div>punchup LLC<=
/div><div><a href=3D"mailto:pierre@punchup.com" target=3D"_blank">pierre@pu=
nchup.com</a></div>
<br>

--f46d04426aa49f224b04bce03a03--