Stewart Gordon wrote:
On 19/10/2010 23:23, Jonathan M Davis wrote:
<snip>
Perhaps, but there is no real benefit in throwing anything other than
an Exception (or Error upon occasion) and if we allow you to throw
anything than catch(Exception e) won't catch them all. It also would
pretty much violate nothrow since nothrow guarantees that no
Exceptions are thrown from that function, and if you can throw any
old object anyway...
<snip>
Indeed, "Nothrow functions do not throw any exceptions derived from
class Exception" - seems odd to me.
I think I've had two uses in my time for throwing something that isn't
an Exception:
- in a previous version of SDWF, to handle an awkward corner case in the
Windows dialog API, though I later found a better way of dealing with it
- in the runtime for an Unlambda to D compiler, to serve as the
continuation object, though that could just as well be changed
I hadn't realised until now that D2 had changed to have a Throwable
class and Error and Exception classes derived therefrom. It seems the
intention was to prevent a nothrow function throwing anything other than
an Error, but it wasn't quite said right. So any solution should
probably prevent circumvention by creating a whole new subclass of
Throwable. (By a quick look through the Java API docs, checked
exception classes are defined as Throwable minus the RuntimeException
and Error subclasses.)
Stewart.
nothrow actually prevents you from throwing anything. A nothrow function
may still perform operations which may throw a compiler-generated Error.
(eg, AssertError, OutOfMemoryError).
It's only a spec change which is required.
