> -----Original Message----- > From: Fernando [mailto:fernando@xxxxxxxxxx] > Sent: Thursday, April 15, 2010 10:24 AM > To: php-general@xxxxxxxxxxxxx > Subject: Re: 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:ash@xxxxxxxxxxxxxxxxxxxx] > >>> Sent: Thursday, April 15, 2010 6:38 AM > >>> To: PHP General List > >>> Subject: 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
