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Date: Sat, 28 Jul 2007 18:20:47 -0600
Message-ID: <E996AAF4A714DF4D9BD59E9418957A2128CF7D@peak8sbs.peak8solutions.local>
In-Reply-To: <200707281905.27822.larry@garfieldtech.com>
Thread-Topic: [PHP-DEV] Re: Type-hinted return values in PHP5?
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References: <74.B1.05050.EADEC964@pb1.pair.com> <08.07.20814.2587AA64@pb1.pair.com> <46ABD596.3060005@zend.com> <200707281905.27822.larry@garfieldtech.com>
To: "Larry Garfield" <larry@garfieldtech.com>,
	<internals@lists.php.net>
Subject: RE: [PHP-DEV] Re: Type-hinted return values in PHP5?
From: jeremy@peak8solutions.com ("Jeremy Privett")

And Zend Studio does this for you already, if you use comment your code
correctly. I really don't see a good use for this, either.

Jeremy

-----Original Message-----
From: Larry Garfield [mailto:larry@garfieldtech.com]=20
Sent: Saturday, July 28, 2007 6:05 PM
To: internals@lists.php.net
Subject: Re: [PHP-DEV] Re: Type-hinted return values in PHP5?

On Saturday 28 July 2007, Stanislav Malyshev wrote:
> > It would give you similar benefits to input type hinting, but
instead of
> > "Functions are now able to force parameters to be objects...", it
would
> > also read "Calling functions are now able to expect return types to
be
> > objects...". If a function was defined to return object Z, but
instead
> > returned false, then obviously there is something wrong and it could
be
> > caught before calling code sees it expecting it to be something
else.
>
> Catching language-level error in application code is usually harder
than
> just handling it in user code. And if you are talking about
distinction
> between false/null and actual object, language level is the wrong
level
> to catch such things.
> If you handle the error in runtime, you could have the check as well.
If
> you don't, the script breaks anyway, so it is not going to help you
much.
> Even more, the return value is the product of the module code, while
> input values are product of the outside code. So when you say "I'm
going
> to process only type X, and I make a requirement for others to pass
only
> X to me", it makes for me more sense than saying "I'm going to return
> only type X so I'm making restriction for myself to return only type
X".
> The latter is more like declaring variable types, which have its
> functions in compiled languages but usually is not happening in
dynamic
> interpreted languages.
> Also, since from the client side there's no way to check if the
function
> you are calling actually does have the return type restriction, it's
> quite hard to program basing on that from the client side. So you
> actually check it in one place (library) and use it in entirely
> different place (client) which is usually bad idea since the client
> becomes too reliant on internal details of the library.
>
> > If I, or someone else decided to make a patch for this, and assuming
it
> > worked exactly like I described, would it be accepted?
>
> I don't know... I personally don't see much use for it, but others may
> disagree.

I think the only serious advantage I could see would be to allow=20
context-assistance IDEs more data, so they could provide
method-completion. =20
As nice a feature as that would be, I don't think it's worth modifying
the=20
language syntax for.  I agree that in a loosely typed language that sort
of=20
thing needs to be checked by the application code anyway.

--=20
Larry Garfield			AIM: LOLG42
larry@garfieldtech.com		ICQ: 6817012

"If nature has made any one thing less susceptible than all others of=20
exclusive property, it is the action of the thinking power called an
idea,=20
which an individual may exclusively possess as long as he keeps it to=20
himself; but the moment it is divulged, it forces itself into the
possession=20
of every one, and the receiver cannot dispossess himself of it."  --
Thomas=20
Jefferson

--=20
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