Functions in PHP: Part 1 - Writing Your Own Functions
John Kary discusses 4 guidelines that if followed will result in clear, focused functions that are easy to read, reason about and reuse. Examples are shown in PHP.
function users_name_begins_with($users, $letter) { $filtered = array(); ! foreach ($users as $user) { if (0 === strpos($user['name'], $letter)) { $filtered[] = $user; } } return $filtered; } 1. Well Named 2. Change vs Same
$a = 1; // global scope ! function test() { global $a; echo $a; // reference to function scope } ! test($a); 1 Avoid using global and its friend $GLOBAL
function users_name_begins_with($users, $letter) { $filtered = array(); ! foreach ($users as $user) { if (0 === strpos($user['name'], $letter)) { $filtered[] = $user; } } return $filtered; } 4. Control In and Out
function users_name_begins_with($users, $letter) { $filtered = array(); ! foreach ($users as $user) { if (0 === strpos($user['name'], $letter)) { $filtered[] = $user; } } return $filtered; } 4. Control In and Out 3. One Return Type 1. Well Named 2. Change vs Same