Maintain legacy code

legacy: require_once, include_once

• alternative: PHP系列 - Autoload 自動載入 « 不像樣工程師 Eric G. Huang's 學習日記

legacy: mysql_query, mysql_fetch_array

• alternative: PHP: PDO::prepare - Manual

legacy: foreach

• alternative: generators

legacy: nested if-else

• alternative: interface

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legacy: 
* alternative: