I am tired of using code like:
$blog = isset($_GET[\'blog\']) ? $_GET[\'blog\'] : \'default\';
but I can\'t use:
$blog = $_
No there is no shorter way than that. You can create a class that handles the $_POST and $_GET variables and just user it whenever you call the blog.
Example:
$blog = Input::put("blog");
The input class will have a static method which will determine when input is either have a $_POST and $_GET or a null value.