RE: [PEAR-DEV] Exception misinformation

I haven't been playing with PHP5's exception handler yet but If you could override the base system Exception class you could do something like the following - which would be similar to the way Pear manages errors (treat the following as pseudo code): Class MyErrorHandler extends System.Exception { Var $ExpectedExceptions=array(); Function __Throw($e) { // If the exception isn't in $ExpectedExceptions - if it is - then nothing is thrown - and // the code continues Throw $e; } Function _ExpectExceptions($ExceptionToExpect) { } } $exceptionHandler= New System.Exception(); $MyErrorHandler = & New MyErrorHanlder(); $exceptionHandler::CustomHandler = &$MyErrorHandler; $MyErrorHanlder::_ExpectExceptions(new exception("something")); ... $MyErrorHanlder::_ExpectExceptions(new exception("something else")); Then later that same day :).. Try { // Do some code that throws the exception // The exception handler determines if there is a custom handler // There is - so it uses that handler (MyErrorHandler) - which we have defined } catch (Exception $e) { // This is something we didn't expect Switch ($e): Case Exception_A: Break; Case Exception_B: Break; Default: Throw $e; Break; } With the above you get the same kinda flexibility as Pear::Exception - but in a PHP5 way. PEAR::Exceptions would be a subclass of the System.Exceptions - so it wouldn’t matter if a PEAR::Exception was thrown or a System::Exception. That way you don't have to mandate what type of exception was thrown and the stack trace would still be meaningful. I guess I should take a look at PHP5 Exceptions and see if the above is possible. Anybody had much of a play with them yet? Regards, David Ashwood -----Original Message----- From: Sergio Carvalho [mailto:sergio.carvalho@portugalmail.com] Sent: Sunday, July 11, 2004 9:53 PM To: pear-dev@lists.php.net Subject: Re: [PEAR-DEV] Exception misinformation Mandate that PEAR Exceptions get thrown by a PEAR method. Instead of: throw new SomeFangledException('aha'); Developers should write: PEAR_Exception::throw(new SomeFangledException('aha')); You can then do all kinds of magic, from silencing to downgrading into Warnings. This has at least one defect: the stack trace for the exception will start inside PEAR_Exception::throw. The first meaningful location will the the next level in the call stack. Complicating a bit the throwing code, one could mandate PEAR_Exceptions are thrown like this: if (PEAR_Exception::shouldThrow($e = new SomeFangledException('aha'))) throw(e); Cheers, Sérgio Carvalho Lukas Smith wrote: > Hi, > > I am wondering if we have come up with some magic to handle the > following issue with exceptions. Currently using PEAR_Error I can build > up a stack of expected errors which should not cause the standard error > handling callback to be called and thereby let local error handling take > over. > > The only way using Exceptions I can quickly come up with is wrapping > every method call with a try catch block including _every_ method call. > Considering that this catch block could get fairly lengthy this could > bloat code considerably. > > Again this shows a huge problem in how exceptions force handling of > every error and at the same time not being able to be easily selectively > suppresed from showing this behaviour. > > Anyways not sure that I thought this thing 100% through considering its > a sunday evening and I am currently watching a movie on TV. If I am > totaly off .. sorry for the noise. > > regards, > Lukas