Re: [PHP] Assigning functions
On May 2, 2008, at 2:42 PM, Craige Leeder wrote:
Hello Philip
First thing first: design patterns are your friend. A good reference
for which, is:
http://www.fluffycat.com/PHP-Design-Patterns/
Second of all. What is the situation in which you are trying to do
this? I can't really think of one where you would do such a thing.
- Craige
Sorry I haven't responded earlier... was away from my computer since
Friday!
First, thanks for the link. Second, because of the way our application
is setup, I am interested in doing this functionality. However,
someone pointed out a very good point - basically abstraction and
classes not needing to know about other classes. So, 'A' knowing about
'C' is "not a good thing" (TM). After thinking twice about it, I won't
take this approach.
However, the reason this came up is because the application is split
up logically between the database layer, security layer, view layer,
logic layer, etc... There is a core class which has generic functions
in it which is called on every request. In this class, other classes
are instantiated and used throughout the app. Kinda like this...
site = new Site ();
}
class Site {
$this->render = new Render ();
}
class Render {
function translate ($template, $arr) {
$content = str_replace (
array_keys($arr),
array_values($arr),
"$template.tpl.php"
);
return $content;
}
function stroke () { }
}
// Somewhere in the app...
$content = $core->site->render->translate('someTemplate', $replace);
?>
Obviously, these are VERY dumbed-down versions of the classes, but
this is the general idea. It all comes down to separation of business
logic from the view from the database, and so on.
Hopefully that's as clear as mud now.
~Philip
On Fri, May 2, 2008 at 3:09 PM, Philip Thompson <[EMAIL PROTECTED]
> wrote:
Hi all. I have several classes. Within each class, a new class is
called. Is
there a way to assign a function in a *deeper* class to be called
in the
first class? Example to follow..
b = new B ();
// I want to do the following. This does not work, of course.
$this->doSomething = $this->b->c->doSomething;
}
}
class B {
function __construct () {
$this->c = new C ();
}
}
class C {
function __construct () { }
function doSomething () { echo "¡Hi!"; }
}
$a = new A ();
// Instead of doing this,
$a->b->c->doSomething();
// I want to do this.
$a->doSomething(); // ¡Hi!
?>
Basically, it's just to shorten the line to access a particular
function.
But, is it possible?!
Thanks,
~Philip
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Re: [PHP] Assigning functions
2008/5/2 Philip Thompson <[EMAIL PROTECTED]>:
> Hi all. I have several classes. Within each class, a new class is called. Is
> there a way to assign a function in a *deeper* class to be called in the
> first class? Example to follow..
>
>class A {
> function __construct () {
> $this->b = new B ();
> // I want to do the following. This does not work, of course.
> $this->doSomething = $this->b->c->doSomething;
> }
> }
>
> class B {
> function __construct () {
> $this->c = new C ();
> }
> }
>
> class C {
> function __construct () { }
> function doSomething () { echo "¡Hi!"; }
> }
>
> $a = new A ();
> // Instead of doing this,
> $a->b->c->doSomething();
>
> // I want to do this.
> $a->doSomething(); // ¡Hi!
> ?>
>
> Basically, it's just to shorten the line to access a particular function..
> But, is it possible?!
Inheritance - http://uk.php.net/extends
class A {
function methodOfA() {}
}
class B extends A {}
B::methodOfA();
(use sparingly - too much inheritance results in a tightly-coupled
hierarchy of classes, which are brittle and hard to re-use).
Or simply express the method in the interface of the exposed class:
class A {
function methodOfA() {}
}
class B {
function methodOfA() {
A::methodOfA();
}
}
b::methodOfA();
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Re: [PHP] Assigning functions
On Fri, May 2, 2008 at 1:48 PM, Nathan Nobbe <[EMAIL PROTECTED]> wrote:
> On Fri, May 2, 2008 at 1:09 PM, Philip Thompson <[EMAIL PROTECTED]>
> wrote:
>
>> Hi all. I have several classes. Within each class, a new class is called.
>> Is there a way to assign a function in a *deeper* class to be called in the
>> first class? Example to follow..
>>
>> > class A {
>>function __construct () {
>>$this->b = new B ();
>>// I want to do the following. This does not work, of course.
>>$this->doSomething = $this->b->c->doSomething;
>>}
>> }
>>
>> class B {
>>function __construct () {
>>$this->c = new C ();
>>}
>> }
>>
>> class C {
>>function __construct () { }
>>function doSomething () { echo "¡Hi!"; }
>> }
>>
>> $a = new A ();
>> // Instead of doing this,
>> $a->b->c->doSomething();
>>
>> // I want to do this.
>> $a->doSomething(); // ¡Hi!
>> ?>
>>
>> Basically, it's just to shorten the line to access a particular function.
>> But, is it possible?!
>
>
> i cant remember what the term is for it phillip (ill look later)
>
i remember what it is know; the principal of least knowledge ;)
http://en.wikipedia.org/wiki/Law_of_Demeter
-nathan
Re: [PHP] Assigning functions
On Fri, May 2, 2008 at 2:03 PM, Craige Leeder <[EMAIL PROTECTED]> wrote:
> ons here) as a simple example something like this
> >
> > class B {
> > //...
> > function doSomething() {
> > return $this->c->doSomething();
> > }
> > }
> >
> > which allows you this in A instances
> >
> > $this->b->doSomething();
> >
> > this is the preferred approach, since A and C instances are loosely
> coupled.
> >
> > of course, if you wanted a to 'know' about c then you could do something
> > like this,
> >
> > class B {
> > // ..
> > function getC() {
> > return $this->c;
> > }
> > }
> >
> > giving you the ability to do this in A instances
> >
> > $this->b->getC()->doSomething();
> >
> > of course now A's knows about C's and your system is more tightly
> coupled.
> >
> > -nathan
> >
>
> Why don't you just do a registry pattern instance then? IE:
>
> class Registry
> {
> private satic objs;
>
> public function __construct()
> {
>
>self::$objs = function_get_args();
> }
>
> public static function __get($obj)
> {
>return self::$objs[$obj];
> }
> }
>
> class A
> {
> ...
> }
>
> class B
> {
> ...
> }
>
> $reg = new Registry( new A(), new B());
>
> Now A and B can access each other through Registry::A and Registry::B
>
> (that code may not function. It's just a general example)
that seems like overkill to me, and anyway, A instances need to get at C
instances.. the Registry would need to be globally available and even then,
if C's and A's could talk to each other through it, it still presents the
issue where A instances know about C instances. its a design decision to be
sure, but likely the cleanest solution will have A instances not knowing
about C instances.
-nathan
Re: [PHP] Assigning functions
ons here) as a simple example something like this
>
> class B {
> //...
> function doSomething() {
> return $this->c->doSomething();
> }
> }
>
> which allows you this in A instances
>
> $this->b->doSomething();
>
> this is the preferred approach, since A and C instances are loosely coupled.
>
> of course, if you wanted a to 'know' about c then you could do something
> like this,
>
> class B {
> // ..
> function getC() {
> return $this->c;
> }
> }
>
> giving you the ability to do this in A instances
>
> $this->b->getC()->doSomething();
>
> of course now A's knows about C's and your system is more tightly coupled.
>
> -nathan
>
Why don't you just do a registry pattern instance then? IE:
class Registry
{
private satic objs;
public function __construct()
{
self::$objs = function_get_args();
}
public static function __get($obj)
{
return self::$objs[$obj];
}
}
class A
{
...
}
class B
{
...
}
$reg = new Registry( new A(), new B());
Now A and B can access each other through Registry::A and Registry::B
(that code may not function. It's just a general example)
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Re: [PHP] Assigning functions
On Fri, May 2, 2008 at 1:09 PM, Philip Thompson <[EMAIL PROTECTED]>
wrote:
> Hi all. I have several classes. Within each class, a new class is called.
> Is there a way to assign a function in a *deeper* class to be called in the
> first class? Example to follow..
>
> class A {
>function __construct () {
>$this->b = new B ();
>// I want to do the following. This does not work, of course.
>$this->doSomething = $this->b->c->doSomething;
>}
> }
>
> class B {
>function __construct () {
>$this->c = new C ();
>}
> }
>
> class C {
>function __construct () { }
>function doSomething () { echo "¡Hi!"; }
> }
>
> $a = new A ();
> // Instead of doing this,
> $a->b->c->doSomething();
>
> // I want to do this.
> $a->doSomething(); // ¡Hi!
> ?>
>
> Basically, it's just to shorten the line to access a particular function.
> But, is it possible?!
i cant remember what the term is for it phillip (ill look later), but thats
sort of considered a bad practice.. primarily since c is composed by b and
a doesnt really know about it, then the way a should talk to c is through
b. so i would create a wrapper method in b (you have many implementation
options here) as a simple example something like this
class B {
//...
function doSomething() {
return $this->c->doSomething();
}
}
which allows you this in A instances
$this->b->doSomething();
this is the preferred approach, since A and C instances are loosely coupled.
of course, if you wanted a to 'know' about c then you could do something
like this,
class B {
// ..
function getC() {
return $this->c;
}
}
giving you the ability to do this in A instances
$this->b->getC()->doSomething();
of course now A's knows about C's and your system is more tightly coupled.
-nathan
Re: [PHP] Assigning functions
Hello Philip
First thing first: design patterns are your friend. A good reference
for which, is:
http://www.fluffycat.com/PHP-Design-Patterns/
Second of all. What is the situation in which you are trying to do
this? I can't really think of one where you would do such a thing.
- Craige
On Fri, May 2, 2008 at 3:09 PM, Philip Thompson <[EMAIL PROTECTED]> wrote:
> Hi all. I have several classes. Within each class, a new class is called. Is
> there a way to assign a function in a *deeper* class to be called in the
> first class? Example to follow..
>
>class A {
> function __construct () {
> $this->b = new B ();
> // I want to do the following. This does not work, of course.
> $this->doSomething = $this->b->c->doSomething;
> }
> }
>
> class B {
> function __construct () {
> $this->c = new C ();
> }
> }
>
> class C {
> function __construct () { }
> function doSomething () { echo "¡Hi!"; }
> }
>
> $a = new A ();
> // Instead of doing this,
> $a->b->c->doSomething();
>
> // I want to do this.
> $a->doSomething(); // ¡Hi!
> ?>
>
> Basically, it's just to shorten the line to access a particular function.
> But, is it possible?!
>
> Thanks,
> ~Philip
> --
> PHP General Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
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[PHP] Assigning functions
Hi all. I have several classes. Within each class, a new class is
called. Is there a way to assign a function in a *deeper* class to be
called in the first class? Example to follow..
b = new B ();
// I want to do the following. This does not work, of course.
$this->doSomething = $this->b->c->doSomething;
}
}
class B {
function __construct () {
$this->c = new C ();
}
}
class C {
function __construct () { }
function doSomething () { echo "¡Hi!"; }
}
$a = new A ();
// Instead of doing this,
$a->b->c->doSomething();
// I want to do this.
$a->doSomething(); // ¡Hi!
?>
Basically, it's just to shorten the line to access a particular
function. But, is it possible?!
Thanks,
~Philip
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
