On Friday, 22 November 2013 at 10:34:12 UTC, Jonathan M Davis
wrote:
On Friday, November 22, 2013 11:24:30 bearophile wrote:
Jonathan M Davis:
> It's not going to work for the compiler to figure out what
> types might work with a given template constraint and then
> have it pick one when you don't tell the template what
> type to be instantiated with.
It could work if the type system become more powerful, but what
are the costs in compiler complexity, compilation times, and
possible bugs in user code?
What's it going to do? Try ever type that it knows about and
see which happens
to work? Try every type that it sees in the template constraint
(particularly
those in is expressions) and see if any of them work? It's a
feature which
sounds like you're trying to write AI. I don't think that even
makes sense to
attempt it. If there's really a type that makes sense by
default, then just
give a default template argument. Why try and make the compiler
more
complicated, particularly when it's questionable that it's a
solvable problem,
and it's pretty much a guarantee that it would have a high
efficiency cost even
if you could pull it off.
- Jonathan M Davis
I just mean:
int t = s.value; // Means int t = s.value!int;
If there's a problem with template instantiatio is the same we
have now.
Now I have to write:
int t = s.value!int;
so if there's a problem with !int, it's just like now.
It's just a syntactic sugar, no new feature... Am I wrong?
