Req #52583 [NEW]: Improved casting and hinting, new magic method __cast()

From: Operating system: Irrelevant PHP version: Irrelevant Package: Class/Object related Bug Type: Feature/Change Request Bug description:Improved casting and hinting, new magic method __cast() Description: ------------ Type casting in PHP is currently limited to the builtin types. It would be very useful (IMO) if one could cast a value/variable to a class. And also type hinting could be improved by casting instead of type checking only. I suggest to solve this by introducing a new magic method for classes, called "__cast()", that accepts the value to cast as parameter. I see two possible solutions for its functionality: (1) __cast() replaces the constructor method This will force the developer to move logics from the constructor into a separate function/method (which isn't even so bad) or to copy his code (which is indeed bad). If the function returns with the boolean value "false", the default error mechanism is started saying something like "cast to XYZ not allowed". (2) __cast() acts like a static constructor The code must return the casted result itself. That means one would implement some logics to transform the given value to the needed constructor parameters and create a new instance on his own. To handle an unsupported value the method would throw an exception or an error. The negative (or let's say curious) thing about this solution is, that this cast method could also return a value of a totally different type (see example). Test script: --------------- // see patch file Expected result: ---------------- // working cast Actual result: -------------- // parse errors -- Edit bug report at http://bugs.php.net/bug.php?id=52583&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=52583&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=52583&r=trysnapshot53 Try a snapshot (trunk): http://bugs.php.net/fix.php?id=52583&r=trysnapshottrunk Fixed in SVN: http://bugs.php.net/fix.php?id=52583&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=52583&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=52583&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=52583&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=52583&r=needscript Try newer version: http://bugs.php.net/fix.php?id=52583&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=52583&r=support Expected behavior: http://bugs.php.net/fix.php?id=52583&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=52583&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=52583&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=52583&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=52583&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=52583&r=dst IIS Stability: http://bugs.php.net/fix.php?id=52583&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=52583&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=52583&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=52583&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=52583&r=mysqlcfg