Dynamic constant name in PHP
To use dynamic constant names in your class you can use reflection feature (since php5):
$thisClass = new ReflectionClass(__CLASS__);
$thisClass->getConstant($constName);
For example: if you want to filter only specific (SORT_*) constants in the class
class MyClass
{
const SORT_RELEVANCE = 1;
const SORT_STARTDATE = 2;
const DISTANCE_DEFAULT = 20;
public static function getAvailableSortDirections()
{
$thisClass = new ReflectionClass(__CLASS__);
$classConstants = array_keys($thisClass->getConstants());
$sortDirections = [];
foreach ($classConstants as $constName) {
if (0 === strpos($constName, 'SORT_')) {
$sortDirections[] = $thisClass->getConstant($constName);
}
}
return $sortDirections;
}
}
var_dump(MyClass::getAvailableSortDirections());
result:
array (size=2)
0 => int 1
1 => int 2
http://dk.php.net/manual/en/function.constant.php
echo constant($constant_name);
And to demonstrate that this works with class constants too:
class Joshua {
const SAY_HELLO = "Hello, World";
}
$command = "HELLO";
echo constant("Joshua::SAY_$command");