#50368 [NEW]: Need variable default function param values, undefine(), or "semi-constants"

From: merlinyoda at dotproject dot net Operating system: N/A PHP version: 5.3.1 PHP Bug Type: Feature/Change Request Bug description: Need variable default function param values, undefine(), or "semi-constants" Description: ------------ Somewhat picking up on Bug #8577 here as I see some potentially legitimate uses for an "unset" function or some functional equivalent as a way to temporarily set a static value based on an expression. The replies in the last bug were a bit flippant on both sides so I hope to get a better resolution as I see this as a potential step towards another degree of untapped flexibility and ability to minimize code. The following function definitions are not valid in PHP: function connectFunct($user_name, $password, $server = getHostName(), $port=3306) { //some code } function connectVar($user_name, $password, $server = $_SERVER["SERVER_NAME"], $port=3306) { //some code } at present the only workaround is to have a "flag" value and reassign the variable as needed like so: function connectFunct($user_name, $password, $server = null, $port=3306) { if ($server === null) { $server = getHostName(); } //some code } function connectVar($user_name, $password, $server = null, $port=3306) { if ($server === null) { $server = $_SERVER["SERVER_NAME"]; } //some code } However the need may easily arise where the "flag" value chosen becomes a value that triggers some other behavior (e.g. null should be an erroneous value if passed). If a constant could be redefined or undefined to more accurately reflect the current state of the value of function call or variable it would allow for a less "hackish" workaround. Example using "undefine()": if (defined('CONNECT_SERVER')) { $prev_connect_val = CONNECT_SERVER; undefine('CONNECT_SERVER'); } define ('CONNECT_SERVER', getHostName()); function connectFunct($user_name, $password, $server = CONNECT_SERVER, $port=3306) { //some code } undefine('CONNECT_SERVER'); if (is_set($prev_connect_val)) { define ('CONNECT_SERVER', $prev_connect_val); } Alternately, you could have another class of constants which are designed for the purpose of temporary value storage (i.e. "semi-constants" mentioned in summary): Example using "semi-constant" function define_temp(): define_temp ('CONNECT_SERVER', getHostName()); function connectFunct($user_name, $password, $server = CONNECT_SERVER, $port=3306) { //some code } undefine_temp('CONNECT_SERVER'); //may not be necessary depending on implementation of "semi-constants" -- Edit bug report at http://bugs.php.net/?id=50368&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=50368&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=50368&r=trysnapshot53 Try a snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=50368&r=trysnapshot60 Fixed in SVN: http://bugs.php.net/fix.php?id=50368&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=50368&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=50368&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=50368&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=50368&r=needscript Try newer version: http://bugs.php.net/fix.php?id=50368&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=50368&r=support Expected behavior: http://bugs.php.net/fix.php?id=50368&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=50368&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=50368&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=50368&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=50368&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=50368&r=dst IIS Stability: http://bugs.php.net/fix.php?id=50368&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=50368&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=50368&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=50368&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=50368&r=mysqlcfg