PHP7 Scalar Type Hinting

php5-type-hinting.php

<?php
/**
 * PHP5 Type Hinting Example.
 *
 * @copyright 2016 SqueezyWeb
 * @author Mattia Migliorini <[email protected]>
 */

/**
 * Array Type Hinting.
 */
function setOptions(array $options) {
	var_dump($options);
}

// Call setOptions() passing an array.
setOptions(array());
// Output:
// array(0) {
// }

// Call setOptions() passing something else (a string in this case).
setOptions('foo');
// Result:
// PHP Warning:  Uncaught TypeError: Argument 1 passed to setOptions() must be of the type array, string given

/**
 * String Type Hinting.
 */
function setValue(string $value) {
	var_dump($value);
}

setValue('foo');
// Result:
// PHP Catchable fatal error:  Argument 1 passed to setValue() must be an instance of string, string given

php7-type-hinting-casting.php

<?php
/**
 * PHP7 Type Hinting with Casting Example.
 * 
 * @copyright 2016 SqueezyWeb
 * @author Mattia Migliorini <[email protected]>
 */

/**
 * Boolean Type Hinting.
 */
function setBool(bool $bool) {
  var_dump($bool);
}

// Call setBool() passing a boolean.
setBool(true);
// Output:
// bool(true)

// Call setBool() passing a string.
setBool('foo');
// Output:
// bool(true)

// Call setBool() passing an empty string.
setBool('');
// Output:
// bool(false)

// Call setBool() passing an integer.
setBool(1);
// Output:
// bool(true)

// Call setBool() passing a negative integer.
setBool(-1);
// Output:
// bool(true)

// Call setBool() passing zero.
setBool(0);
// Output:
// bool(false)

// Call setBool() passing an array.
setBool([]);
// Result:
// PHP Warning:  Uncaught TypeError: Argument 1 passed to setBool() must be of the type boolean, array given

/**
 * Integer Type Hinting.
 */
function setInt(int $number) {
  var_dump($number);
}

// Call setInt() passing an integer.
setInt(10);
// Output:
// int(10)

// Call setInt() passing a numeric string.
setInt('10');
// Output:
// int(10)

// Call setInt() passing a non-numeric string.
setInt('foo');
// Result:
// PHP Warning:  Uncaught TypeError: Argument 1 passed to setInt() must be of the type integer, string given

php7-type-hinting-strict.php

<?php
/**
 * PHP7 Strict Type Hinting Example.
 * 
 * @copyright 2016 SqueezyWeb
 * @author Mattia Migliorini <[email protected]>
 */

// Force Type Hinting to do a strict type check (the same as ===).
declare(strict_types=1);

function setBool(bool $bool) {
  var_dump($bool);
}

// Call setBool() passing a string.
setBool('foo');
// Result:
// PHP Fatal error:  Uncaught TypeError: Argument 1 passed to setBool() must be of the type boolean, string given

php7-type-hinting.php

<?php
/**
 * PHP7 Type Hinting Example.
 * 
 * @copyright 2016 SqueezyWeb
 * @author Mattia Migliorini <[email protected]>
 */

/**
 * String Type Hinting.
 */
function setValue(string $value) {
	var_dump($value);
}

// Call setValue() passing a string.
setValue('foo');
// Output:
// string(3) "foo"

// Call setValue() passing an array.
setValue([]);
// Result:
// PHP Warning:  Uncaught TypeError: Argument 1 passed to setValue() must be of the type string, array given