php - how is it that PDO can have methods with typed string parameters, but I can't do this in my own functions? -

if create instance of pdo , call pdo->quote('test') works no problems.

if @ defination of pdo quote method looks this:

/**  * quotes string use in query.  * pdo::quote() places quotes around input string (if required) , escapes special characters within input string, using quoting style appropriate underlying driver.  *  * @param string $string string quoted.  * @param int $parameter_type provides data type hint drivers have alternate quoting styles.  *  * return string  */ function quote(string $string, int $parameter_type) {/* method implementation */} 

note parameters actully have types defined in method signature, string , int.

now if create function this:

function test(string $test) {     return $test; } 

and attempt call this:

echo test('test'); 

it fails following error:

( ! ) catchable fatal error: argument 1 passed test() must instance of string, string given, called in [path_removed]testtypehinting.php on line 36 , defined in [path_removed]testtypehinting.php on line 2 

how come pdo can it, can't?

regards,

scott

it's documentation , real code. read type hinting.

type hints can not used scalar types such int or string

but there moving implement scalar type hinting.

you can add phpdoc documentation function.

/**  * test function  * @param string $test  * @return string  */ function test($test) {     return $test; } 

also read how read function definition