teach PHP and related

knowledge areas of PHP

• uses of PHP : CLI for REPL and script execution . HTTP execution in HTTPd and "PHP -S" .
• expressions with literals and operators . uses of math functions . rounding . randomization .
• variables : visibility , create & destroy , read & write accesses , expressions with variables also .
• strings : literals of it , interpolation , concatenation , length , trim , case transforms .
• function : declare it , use it with params , use it with return values .
• array : literals of it , indexing , append , sort , nesting .
• control flow : decisions , loops , keywords like return or break or continue .
• OOP : classes & objects , members and static members , constructors , access specifiers , inheritance .
• include / require , include_once / require_once , autoload .
• HTTP context : $_REQUEST , $_GET , $_POST , $_COOKIE , $_SESSION , $_SERVER .
• output buffering : ob_start() , ob_end() .
• regular expressions : match , replace . regex testing tools .
• files : file_get_contents() , file_put_contents() .
• PDO for SQL , ORM for SQL ( RedBeanPHP ? )
• JSON serialization . use for files , use for network ( HTTP protocol ? ) .