On 2011-09-23 08:42, Daniel Murphy wrote:
"Jacob Carlborg"<[email protected]> wrote in message
news:[email protected]...
What I'm saying is that you can ignore the returned value of a delegate
therefore I think it should be possible implicitly convert a delegate
returning a value, to a delegate returning void. The same for function
pointers as well. Example:
void main ()
{
int delegate () bar = { return 1; };
void delegate () foo = bar;
int a = bar(); // here we call "bar" and handles the return value
bar(); // here we call "bar" and ignores the return value
foo(); // here we call "foo", same as the line above
}
I can see the appeal, but the abi makes it difficult. As Walter said, what
if the return value requires destruction by the caller? What if the return
is done through nrvo? While they're called the same, the code generator
handles them very differently. If it works, it should work for all cases.
Don't forget that you can trivially convert to a delegate returning void
with the following syntax:
void delegate () foo = { bar(); };
Why can't the compiler do something similar automatically. Then we won't
have the problem if a lambda returns void or a value.
--
/Jacob Carlborg
