Posted by Morgan Doocy on 10/19/45 11:30

I'm trying to figure out if PHP has the facility to reference containing, non-parent objects. I have three classes, embedded hierarchically, but which are NOT extended classes of their containing objects. I'd like to be able to reference variables in the higher-level objects from the lower-level objects.

To illustrate:

<?php

class Country {
var $name;
var $states;

function Country($name = '', $states = array()) {
$this->name = $name;
$this->states = $states;
}
}

class State {
var $name;
var $cities;

function State($name = '', $cities = array()) {
$this->name = $name;
$this->cities = $cities;
}
}

class City {
var $name;

fuction City($name = '') {
$this->name = '';
}

function name_with_state() {
return "$this->name, " . /* parent node reference */->name;
}
}

$countries = array (
'USA' => new Country('United States',
array (
'WA' => new State('Washington',
array (
'SEA' => new City('Seattle'),
'GEG' => new City('Spokane')
)
),
'CA' => new State('California',
array (
'LAX' => new City('Los Angeles'),
'SFO' => new City('San Francisco')
)
)
)
)
);

echo $countries['USA']->states['WA']->cities['SEA']->name_with_state();
// Output: 'Seattle, Washington'

?>

Obviously, just extending Country doesn't make sense: a State isn't a type of Country, and a City isn't a type of State -- but States are part of Countries, and Cities are part of States. Plus, if City was just an extended State (which in turn is an extended Country), it would contain both a $states and a $cities variable. Which doesn't make sense.

What, if anything, do I replace /* parent node reference */ with in City::name_with_state()?

Thanks,

Morgan

• Next in forum: Re: Inserting NULL Integer Values
• Prev in forum: Re: <select> not populating form fields (php,mysql)
• Thread view: Referencing Containing (Non-Parent) Object?

[Reply to this message]