是否有可能让函数变量包含参数？

Question

I have the following code:

$posted_on = new DateTime($date_started);
$today = new DateTime('today');
$yesterday = new DateTime('yesterday');
$myFormat = 'format(\'Y-m-d\')';

if($posted_on->{$myFormat} == $today->{$myFormat}) {
    $post_date = 'Today';
}
elseif($posted_on->{$myFormat} == $yesterday->{$myFormat}) {
    $post_date = 'Yesterday';
}
else{
    $post_date = $posted_on->format('F jS, Y');
}

echo 'Started '.$post_date;

As you can see I'm trying to use "format('Y-m-d')" many times, and don't want to type it in multiple places, so I'm trying to simply put it in a variable and use that. However, I get a notice: Message: Undefined property: DateTime::$format('Y-m-d')

What would be the right way to go about doing this?

Answer 1

No, but you can curry the function:

$myFormat = function($obj) {return $obj->format("Y-m-d");};

if( $myFormat($posted_on) == $myFormat($today))

Or more cleanly:

class MyDateTime extends DateTime {
    public function format($fmt="Y-m-d") {
        return parent::format($fmt);
    }
}
$posted_on = new MyDateTime($date_started);
$today = new MyDateTime("today");
$yesterday = new MyDateTime("yesterday");

if( $posted_on->format() == $today->format()) {...