Author: allison Date: Tue Sep 16 13:12:27 2008 New Revision: 31186 Modified: trunk/docs/pdds/pdd23_exceptions.pod
Log: [pdd] Clarifying the description of the 'throw' opcode, and the necessary interface of thrown exceptions. Modified: trunk/docs/pdds/pdd23_exceptions.pod ============================================================================== --- trunk/docs/pdds/pdd23_exceptions.pod (original) +++ trunk/docs/pdds/pdd23_exceptions.pod Tue Sep 16 13:12:27 2008 @@ -64,27 +64,17 @@ Pop the most recently pushed exception handler off the exception handler stack. -=item B<throw I<EXCEPTION>> - -Throw an exception consisting of the given I<EXCEPTION> PMC. Active exception -handlers (if any) will be invoked with I<EXCEPTION> as the only parameter. - - =item B<throw I<EXCEPTION> [ , I<CONTINUATION> ]> -Throw an exception consisting of the given I<EXCEPTION> PMC after taking -a continuation at the next opcode. When a I<CONTINUATION> is passed in, -it will use that instead. Active exception handlers (if any) will be -invoked with I<EXCEPTION> and the given continuation as parameters. - -Any type of PMC can be thrown as an exception. However, if there's any chance -of cross-language calls -- and in a Parrot environment, cross-language -operations are kind of the point -- then you should be prepared to catch -exception classes you would never have thrown yourself. - -That said, it is recommended that any thrown PMC that can possibly escape your -private sandbox should meet the minimal interface requirements of the -C<parrot;exception> class, described below. +Throw an exception consisting of the given I<EXCEPTION> PMC, after taking a +continuation at the next opcode. When a I<CONTINUATION> is passed in, it will +use that instead of generating a new continuation. Active exception handlers +(if any) will be invoked with I<EXCEPTION> as the only parameter, and the +return continuation stored within that exception object. + +PMCs other than Parrot's Exception PMC may also be thrown, but they must +support the interface of an Exception PMC. An HLL may implement throwing any +arbitrary type of PMC, by storing that PMC as the payload of an Exception PMC. Exception handlers can resume execution immediately after the C<throw> opcode by invoking the resume continuation which is stored in the exception object.
