RE: [PHP] class attributes and __construct
Hi Ashley,
-Original Message-
From: Ashley Sheridan [mailto:a...@ashleysheridan.co.uk]
Sent: Thursday, April 15, 2010 6:38 AM
To: PHP General List
Subject: [PHP] class attributes and __construct
I think this is probably going to end up as one of those coders'
preference type of things, but I was wondering what was considered the
general best approach.
When creating a class, you can define default values for the object in
the class itself, and within the __construct function. Now, while I see
the advantage to using __construct to set properties that might depend
on a variable, what would be the best approach for any values that
might
likely remain at a default value and only ever change in a few rare
circumstances?
For example:
class Person
{
public $right_handed = true;
I recommend setting it to private or protected instead of public to protect the
integrity of the app. And add a get method/function to obtain the value.
function __construct($name, $height)
{
$this-name = $name;
$this-height = $height;
}
function set_hand($side)
{
if($side == 'left'
{
$this-right_handed = false;
}
else
{
$this-right_handed = true;
}
}
}
Now, this is a simple example, but a value like $right_handed should
only ever change if it's not the typical. As most people are
right-handed it would make sense to set it to true and allow it to be
changed to false as necessary. What I'm wonder is, where is the best
place to set it to true, in the list of class properties at the top, or
in the __construct() function?
I know I could move it to __construct and give it a default value in
the
arguments list, but that brings it's own problems. What if the argument
list grows too big, and which attribute would be deemed more important
than another that you might want to override it without specifying
every
other? Is there a rule of thumb as to what belongs in __construct and
what does not?
Thanks,
Ash
http://www.ashleysheridan.co.uk
As for setting the default value in the construct, I recommend not to because
should PHP support overloading later, you can then have another method/function
to change its non-default value along with the initial parameters for the
class. I use the constructor to set initial parameters for the class or
initialize any class specific settings such as connection for DBAL.
Regards,
Tommy
--
PHP General Mailing List (http://www.php.net/)
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RE: [PHP] class attributes and __construct
On Thu, 2010-04-15 at 07:42 -0700, Tommy Pham wrote:
Hi Ashley,
-Original Message-
From: Ashley Sheridan [mailto:a...@ashleysheridan.co.uk]
Sent: Thursday, April 15, 2010 6:38 AM
To: PHP General List
Subject: [PHP] class attributes and __construct
I think this is probably going to end up as one of those coders'
preference type of things, but I was wondering what was considered the
general best approach.
When creating a class, you can define default values for the object in
the class itself, and within the __construct function. Now, while I see
the advantage to using __construct to set properties that might depend
on a variable, what would be the best approach for any values that
might
likely remain at a default value and only ever change in a few rare
circumstances?
For example:
class Person
{
public $right_handed = true;
I recommend setting it to private or protected instead of public to protect
the integrity of the app. And add a get method/function to obtain the value.
function __construct($name, $height)
{
$this-name = $name;
$this-height = $height;
}
function set_hand($side)
{
if($side == 'left'
{
$this-right_handed = false;
}
else
{
$this-right_handed = true;
}
}
}
Now, this is a simple example, but a value like $right_handed should
only ever change if it's not the typical. As most people are
right-handed it would make sense to set it to true and allow it to be
changed to false as necessary. What I'm wonder is, where is the best
place to set it to true, in the list of class properties at the top, or
in the __construct() function?
I know I could move it to __construct and give it a default value in
the
arguments list, but that brings it's own problems. What if the argument
list grows too big, and which attribute would be deemed more important
than another that you might want to override it without specifying
every
other? Is there a rule of thumb as to what belongs in __construct and
what does not?
Thanks,
Ash
http://www.ashleysheridan.co.uk
As for setting the default value in the construct, I recommend not to because
should PHP support overloading later, you can then have another
method/function to change its non-default value along with the initial
parameters for the class. I use the constructor to set initial parameters
for the class or initialize any class specific settings such as connection
for DBAL.
Regards,
Tommy
Maybe my example wasn't the best, but I did mean that my public variable
there was a value that should be initially set with the class
initialisation I realise the differences between public, private and
protected variables, that wasn't my question. What I wanted to know was
if there was a convention about what specific properties should be set
through the public $var = method and what should be left for the
__construct function?
For example, which would be better here (assuming a variable number of
variables that might be set this way:
class House
{
public $roof = true;
}
class House
{
function __construct()
{
$this-roof = true;
}
}
Aside from the amount of typing (which isn't a serious consideration for
me anyway) and assuming that such variable initialisation will not rely
on variable input but will be fixed with the option of a class method to
change the value later, what would be the preferred method and are there
any caveats I'm unaware of right now (as I'm aware of none so far) to
either method?
Thanks,
Ash
http://www.ashleysheridan.co.uk
Re: [PHP] class attributes and __construct
Hello Ashely,
I would initialize the variable when I'm defining it as there isn't much
of a point of doing it in the constructor unless I'm having the value
changed by a parameter.
In my opinion:
class House
{
public $roof = true;
}
is the way to go.
Fernando.
On 15/04/2010 11:54, Ashley Sheridan wrote:
On Thu, 2010-04-15 at 07:42 -0700, Tommy Pham wrote:
Hi Ashley,
-Original Message-
From: Ashley Sheridan [mailto:a...@ashleysheridan.co.uk]
Sent: Thursday, April 15, 2010 6:38 AM
To: PHP General List
Subject: [PHP] class attributes and __construct
I think this is probably going to end up as one of those coders'
preference type of things, but I was wondering what was considered the
general best approach.
When creating a class, you can define default values for the object in
the class itself, and within the __construct function. Now, while I see
the advantage to using __construct to set properties that might depend
on a variable, what would be the best approach for any values that
might
likely remain at a default value and only ever change in a few rare
circumstances?
For example:
class Person
{
public $right_handed = true;
I recommend setting it to private or protected instead of public to protect the
integrity of the app. And add a get method/function to obtain the value.
function __construct($name, $height)
{
$this-name = $name;
$this-height = $height;
}
function set_hand($side)
{
if($side == 'left'
{
$this-right_handed = false;
}
else
{
$this-right_handed = true;
}
}
}
Now, this is a simple example, but a value like $right_handed should
only ever change if it's not the typical. As most people are
right-handed it would make sense to set it to true and allow it to be
changed to false as necessary. What I'm wonder is, where is the best
place to set it to true, in the list of class properties at the top, or
in the __construct() function?
I know I could move it to __construct and give it a default value in
the
arguments list, but that brings it's own problems. What if the argument
list grows too big, and which attribute would be deemed more important
than another that you might want to override it without specifying
every
other? Is there a rule of thumb as to what belongs in __construct and
what does not?
Thanks,
Ash
http://www.ashleysheridan.co.uk
As for setting the default value in the construct, I recommend not to because
should PHP support overloading later, you can then have another method/function
to change its non-default value along with the initial parameters for the
class. I use the constructor to set initial parameters for the class or
initialize any class specific settings such as connection for DBAL.
Regards,
Tommy
Maybe my example wasn't the best, but I did mean that my public variable
there was a value that should be initially set with the class
initialisation I realise the differences between public, private and
protected variables, that wasn't my question. What I wanted to know was
if there was a convention about what specific properties should be set
through the public $var = method and what should be left for the
__construct function?
For example, which would be better here (assuming a variable number of
variables that might be set this way:
class House
{
public $roof = true;
}
class House
{
function __construct()
{
$this-roof = true;
}
}
Aside from the amount of typing (which isn't a serious consideration for
me anyway) and assuming that such variable initialisation will not rely
on variable input but will be fixed with the option of a class method to
change the value later, what would be the preferred method and are there
any caveats I'm unaware of right now (as I'm aware of none so far) to
either method?
Thanks,
Ash
http://www.ashleysheridan.co.uk
RE: [PHP] class attributes and __construct
-Original Message-
From: Fernando [mailto:ferna...@ggtours.ca]
Sent: Thursday, April 15, 2010 10:24 AM
To: php-general@lists.php.net
Subject: Re: [PHP] class attributes and __construct
Hello Ashely,
I would initialize the variable when I'm defining it as there isn't
much
of a point of doing it in the constructor unless I'm having the value
changed by a parameter.
In my opinion:
class House
{
public $roof = true;
}
is the way to go.
Fernando.
That's what I meant. IMO, it's also a micro optimization since it doesn't need
an extra step of looking the variable and assigning the value when it's not
needed. Plus, it allows better polymorphism through methods/functions.
Regards,
Tommy
On 15/04/2010 11:54, Ashley Sheridan wrote:
On Thu, 2010-04-15 at 07:42 -0700, Tommy Pham wrote:
Hi Ashley,
-Original Message-
From: Ashley Sheridan [mailto:a...@ashleysheridan.co.uk]
Sent: Thursday, April 15, 2010 6:38 AM
To: PHP General List
Subject: [PHP] class attributes and __construct
I think this is probably going to end up as one of those coders'
preference type of things, but I was wondering what was considered
the
general best approach.
When creating a class, you can define default values for the object
in
the class itself, and within the __construct function. Now, while I
see
the advantage to using __construct to set properties that might
depend
on a variable, what would be the best approach for any values that
might
likely remain at a default value and only ever change in a few rare
circumstances?
For example:
class Person
{
public $right_handed = true;
I recommend setting it to private or protected instead of public to
protect the integrity of the app. And add a get method/function to
obtain the value.
function __construct($name, $height)
{
$this-name = $name;
$this-height = $height;
}
function set_hand($side)
{
if($side == 'left'
{
$this-right_handed = false;
}
else
{
$this-right_handed = true;
}
}
}
Now, this is a simple example, but a value like $right_handed
should
only ever change if it's not the typical. As most people are
right-handed it would make sense to set it to true and allow it to
be
changed to false as necessary. What I'm wonder is, where is the
best
place to set it to true, in the list of class properties at the
top, or
in the __construct() function?
I know I could move it to __construct and give it a default value
in
the
arguments list, but that brings it's own problems. What if the
argument
list grows too big, and which attribute would be deemed more
important
than another that you might want to override it without specifying
every
other? Is there a rule of thumb as to what belongs in __construct
and
what does not?
Thanks,
Ash
http://www.ashleysheridan.co.uk
As for setting the default value in the construct, I recommend not
to because should PHP support overloading later, you can then have
another method/function to change its non-default value along with the
initial parameters for the class. I use the constructor to set initial
parameters for the class or initialize any class specific settings such
as connection for DBAL.
Regards,
Tommy
Maybe my example wasn't the best, but I did mean that my public
variable
there was a value that should be initially set with the class
initialisation I realise the differences between public, private and
protected variables, that wasn't my question. What I wanted to know
was
if there was a convention about what specific properties should be
set
through the public $var = method and what should be left for the
__construct function?
For example, which would be better here (assuming a variable number
of
variables that might be set this way:
class House
{
public $roof = true;
}
class House
{
function __construct()
{
$this-roof = true;
}
}
Aside from the amount of typing (which isn't a serious consideration
for
me anyway) and assuming that such variable initialisation will not
rely
on variable input but will be fixed with the option of a class method
to
change the value later, what would be the preferred method and are
there
any caveats I'm unaware of right now (as I'm aware of none so far) to
either method?
Thanks,
Ash
http://www.ashleysheridan.co.uk
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] class attributes and __construct
On Thursday 15 April 2010 08:37:40 am Ashley Sheridan wrote: I know I could move it to __construct and give it a default value in the arguments list, but that brings it's own problems. What if the argument list grows too big, and which attribute would be deemed more important than another that you might want to override it without specifying every other? Is there a rule of thumb as to what belongs in __construct and what does not? Thanks, Ash http://www.ashleysheridan.co.uk I tend to favor setting the default with the property itself rather than in the constructor, even if I expect the constructor to specify it. I really really hate having undefined variables. :-) So even if, for instance, I'm going to pass in a db connection object in the constructor I will define it in the class and set it to NULL rather than not setting to anything. OK, I'm a little OCD, but it works. :-) --Larry Garfield -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
