Known bugs, fixed here.

mysql.php throws a diferent than "PDOException". This leads to an ugly error page when a user tries to install to a database that doesn't exist. This catches the error. We might consider trying to create the database. Reference https://github.com/anchorcms/anchor-cms/issues/638
No sir,

First, in your example, $database[host] shouldn't resolve without encapsulating "host" in quotes. I believe it should throw a constant error.

Secondly, it is completely valid syntax.

Try it here.

http://codepad.org/yImzHL47