On 8/24/2013 1:09 PM, H. S. Teoh wrote:
On Sat, Aug 24, 2013 at 12:27:37PM -0700, Walter Bright wrote:
[...]
Not a bad idea, but it has some issues:
1. scope(failure) takes care of most of it already
2. I'm not sure this is a problem that needs solving, as the DIP
points out, these issues are already easily dealt with. We should be
conservative about adding more syntax.
3. What if the destructor needs to do more than just unwind the
transactions? Where does that code fit in?
I think it's unhelpful to conflate scope(this) with dtors. They are
related, but -- and I guess I was a bit too strong about saying dtors
are redundant -- if we allow both, then scope(this) can be reserved for
transactions, and you can still put code in ~this() to do non-trivial
cleanups.
If you take out automatic dtor generation, I see no difference between
scope(this) and scope(failure).
4. The worst issue is the DIP assumes there is only one constructor,
from which the destructor is inferred. What if there is more than
one constructor?
This is not a problem. If there is more than one constructor, then only
those scope(this) statements in the ctor that were actually encountered
will trigger when the object reaches the end of its lifetime.
Do you mean multiple dtors will be generated, one for each constructor?
