I am a new intern at a company and I was looking through someone's code, when I saw this notation:
if($o_eventNode->{$calOption}[0]['value'] == 1)
I don't understand the part with the curly brackets. Is there some other way to type it? And what is the advantage of that syntax?
With that syntax you are able to call methods and variables of a class dynamically without knowing their respective name (also see variable variable names in the docs).
/edit: updated the answer with a more sophisticated example, I hope this is easier to understand. Fixed the original code, this one should actually work.
Example:
<?php
class Router {
// respond
//
// just a simple method that checks wether
// we got a method for $route and if so calls
// it while forwarding $options to it
public function respond ($route, $options) {
// check if a method exists for this route
if (method_exists($this, 'route_'.$route) {
// call the method, without knowing which
// route is currently requested
print $this->{'route_'.$route}($options);
} else {
print '404, page not found :(';
}
}
// route_index
//
// a demo method for the "index" route
// expecting an array of options.
// options['name'] is required
public function route_index ($options) {
return 'Welcome home, '.$options['name'].'!';
}
}
// now create and call the router
$router = new Router();
$router->respond('foo');
// -> 404, because $router->route_foo() does not exist
$router->respond('index', array('name'=>'Klaus'));
// -> 'Welcome home Klaus!'
?>
The contents of the variable $calOption will be used as the name of the class member from $o_eventNode. The curly brackets are there, to clearly mark the end of the variable, so it is distinct that not $calOption[0]['value'] is meant instead.
See: http://php.net/language.variables.variable.php for an explanation of this ambiguity problem when using variable variables with arrays.
