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Date: Sun, 18 Nov 2007 21:50:14 -0500
Sender: david.coallier@gmail.com
To: "Hannes Magnusson" <hannes.magnusson@gmail.com>
Cc: "Cristian Rodriguez" <judas.iscariote@gmail.com>, internals@lists.php.net
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References: <1195140437.23612.5.camel@sbarrow-desktop>
	 <10610581037.20071115172619@marcus-boerger.de>
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	 <7d5a202f0711181452h3b6a26b8x5b838b585c552765@mail.gmail.com>
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Subject: Re: [PHP-DEV] [PATCH] Optional scalar type hinting
From: davidc@php.net ("David Coallier")

On Nov 18, 2007 7:24 PM, Hannes Magnusson <hannes.magnusson@gmail.com> wrote:
> On Nov 19, 2007 12:13 AM, David Coallier <davidc@php.net> wrote:
> > I was thinking at something along the lines of objects also for instance:
> >
> > $i = new Integer(33);
> >
> > function foo(Integer $var) {
> > }
> >
> > foo ($i); else it emits a fatal error. But also if you do
> >
> > $i = "Name"; that would emit a fatal error because the value is
> > suposed to be an int. This might look a bit too much like java, but as
> > an extension it could be something quite interesting I believe.
> >
> > String, Object, Integer, Scalar, Float  and what else.
> >
> > So thinking of something like
> >
> > $string = new String("Foo");
> > $string = "bar" or $string->setValue("Bar"); would do
> >
> > $float = new Float(4.242);
> > $float->setValue('foobar'); // That emits an error
> > $float->setValue(3.14159);
> >
> > echo $float; (__toString) or echo $float->getValue; to echo it's content/value
> >
> > and so on.
>
> That has got to be the worst idea I've heard on internals for over a month.
> Besides, you can do this in userland already anyway:
>

haha :) Yes, you can do many things in userland.

> <?php
> class InvalidTypeException extends Exception {}
> class UnknownTypeException extends Exception {}
>
> class Types {
>         const INTEGER = 1;
>         const FLOAT   = 2;
>         const STRING  = 3;
>         const OBJECT  = 4;
>         const BOOLEAN = 5;
>
>         private $val, $type;
>
>         public function __construct($val, $type) {
>                 $this->type = $type;
>                 $this->setValue($val);
>         }
>         public function setValue($val) {
>                 switch($this->type) {
>                 case self::INTEGER:
>                         if (!is_int($val)) {
>                                 throw new InvalidTypeException;
>                         }
>                         break;
>
>                 case self::FLOAT:
>                         if (!is_float($val)) {
>                                 throw new InvalidTypeException;
>                         }
>                         break;
>
>                 case self::STRING:
>                         if (!is_string($val)) {
>                                 throw new InvalidTypeException;
>                         }
>                         break;
>
>                 case self::OBJECT:
>                         if (!is_object($val)) {
>                                 throw new InvalidTypeException;
>                         }
>                         break;
>
>                 case self::BOOLEAN:
>                         if (!is_bool($val)) {
>                                 throw new InvalidTypeException;
>                         }
>                         break;
>
>                 default:
>                         throw new UnknownTypeException;
>
>                 }
>                 $this->val = $val;
>         }
>         public function getValue() {
>                 return $this->val;
>         }
>         public function __toString() {
>                 return (string)$this->getValue();
>         }
> }
>
> class Integer extends Types {
>         public function __construct($val) {
>                 parent::__construct($val, Types::INTEGER);
>         }
> }
> class String extends Types {
>         public function __construct($val) {
>                 parent::__construct($val, Types::STRING);
>         }
> }
> class Float extends Types {
>         public function __construct($val) {
>                 parent::__construct($val, Types::FLOAT);
>         }
> }
> class Object extends Types {
>         public function __construct($val) {
>                 parent::__construct($val, Types::OBJECT);
>         }
> }
> class Boolean extends Types {
>         public function __construct($val) {
>                 parent::__construct($val, Types::BOOLEAN);
>         }
> }
> function type_hint_integer(Integer $val) {
>         echo $val, "\n";
> }
> function type_hint_string(String $val) {
>         echo $val, "\n";
> }
> function type_hint_float(Float $val) {
>         echo $val, "\n";
> }
>
>
>
> type_hint_integer(new Integer(123));
> type_hint_string(new String("string"));
> type_hint_float(new Float(0.25));
>

Nice implementation, so ? Still more code to include in your code.
Anyways, the "Optional" part in the subject means ... optional. Which
means that it does not *have* to be used and that the default hinting
will still be loose.

That gives the chance to anyone to use either strongly-typed code or
loosely-typed code. You know as much as I do that it's quite easy to
do (implement - like you just did), but if it's not in by default,
people won't care about doing it or implementing it.

On the other hand, if it's there, some people might be tempted to use
it, and will. But hey.. php's a loosely typed language and it'll
definitely stay that way. But only giving the choice to someone to use
what he feels like is quite interesting in my opinion.

Anyways, no need to get all grumpy, you can just say you don't like
the idea, that'll do just as well. Anyways, that was a thought, it's
quite easy to implement as an extension and would be light and simple
for anyone to either use or ignore it.


> -Hannes
>



-- 
David Coallier,
Founder & Software Architect,
Agora Production (http://agoraproduction.com)
51.42.06.70.18