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Date: Mon, 21 Oct 2019 16:42:25 -0400
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To: Kosit Supanyo <webdevxp.com@gmail.com>
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Subject: Re: [PHP-DEV] 'switch-expression' and the 'type guard' unary operator
 demo
From: mike@newclarity.net (Mike Schinkel)

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> On Oct 20, 2019, at 11:11 PM, Kosit Supanyo <webdevxp.com@gmail.com> =
wrote:
> Ok, so let's look at a scenario. Will we be able to do this in the =
future, if we decide to allow multiple expressions to result in a final =
value?
> $y =3D switch ($x) {
>     case 1 =3D> $arr =3D get_array(), array_pop($arr),
>     case -1 =3D> $arr =3D get_array(), array_unshift($arr),
>     default =3D> null,
> };
>=20
> As I told you in previous reply, I'm working on block-expressions as =
well. So if PHP has block-expressions you can do the same this way:
>=20
> $y =3D switch ($x) {
>     case 1 =3D> eval {
>         $arr =3D get_array();
>         give array_pop($arr);
>     },
>     case -1 =3D> eval {
>         $arr =3D get_array();
>         give array_shift($arr);
>     },
>     default =3D> null,
> };

I know you said you were working on block expressions, but I did not =
view that as the best solution to the question I asked although I see =
that is how you envision it.


> Which is obviously cleaner and more powerful.

That is arguable. I find the solution you proposed above that uses =
`eval()` to be very "busy" visually, and needlessly complex/  You could =
instead simply assume that case statements supports multiple lines with =
the last providing the value, and thus not requiring the use of an =
explicit `eval()`. But to do that would require semi-colon line =
terminators, I think.

Note I also think `eval()` would also be a nice to have, but what would =
be even nicer is if the inline switch did not require use of `eval()` to =
support multiple lines per case.

#fwiw

-Mike






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