TRY_CATCH()

[Andrew Cagney <ac131313@redhat.com>]

Hello,

The exceptions rewrite opens up a key possibility.  It's now possible to 
define a macro such that:

   struct args
   {
     ...
   };

   do_func (void *data)
   {
     struct args *args = data;
     ... do stuff ...;
   }

   func (...)
   {
     struct args args;
     args... = ...;
     struct exception e = catch_exception (..., func, &args, ...)
     switch (e.reason)
       ...
   }

can be replaced with the more compact:

   func (...)
   {
     volatile struct exception e;
     TRY_CATCH (e)
       {
         ... do stuff ...;
       }
     switch (e.reason)
       ...
   }

Yes I know macros a bad, m'kay.  However, this offers a simple way to 
rewrite the code using something more like a real programming languages 
try/catch.

Andrew

PS: I recall this being proposed years ago, but the mechanism proposed 
at the time had a more cumbersom syntax, from memory something like:

   TRY_BEGIN
     ... do stuff ...
   TRY_END;

comments?
Andrew