从静态函数内部引用静态变量

I have the following piece of code, which doesn't work:

<?php
class test{
    public static $var = 'foo';
    public static function printvar(){
        echo "Var value is {self::$var}";
    }
}
test::printvar();
?>

However this works:

<?php
class test{
    public static $var = 'foo';
    public static function printvar(){
        echo "Var value is " . self::$var;
    }
}
test::printvar();
?>

Question is, is there anyway I can access the static variables inside quotes from inside a static method?

By manual:

Functions, method calls, static class variables, and class constants inside {$} work since PHP 5. However, the value accessed will be interpreted as the name of a variable in the scope in which the string is defined. Using single curly braces ({}) will not work for accessing the return values of functions or methods or the values of class constants or static class variables.