On Sun, Jan 25, 2015 at 5:19 AM, Piotr Wygocki
Hi, this library might be very useful in a library I'm involved in. Particularly we've developed an interface for linear programing. In the implementation we needed to ensure that this expression compiles: Column x , y; 0 <= x + y <= 10;
And this:
0 <= x + y >= 10;
does not.
We have very ugly solution now and I guess this is a perfect use case for this library.
Yeah, that would be trivial to check with this. Unfortunately, I can't seem to get it to work consistently across compilers or even consistently within a single compiler. The most compelling thing about this, IMO, is that because it is itself an expression and doesn't require separate statements, it would be usable directly with enable_if, so if it can be made to work portably you could, for example, write a function template that is enabled if a certain operation is *not* supported (or if a certain operation is or is not constexpr), which without a trick like this requires at least another declaration to perform the SFINAE magic with a separate metafunction. With this, everything would be able to be done entirely as a part of the function template declaration itself. -- -Matt Calabrese