Re: constexpr and CTFE
On Sun, 27 Mar 2011 17:50:00 +0300, bearophile wrote: This first question is mostly for D.learn, but below I show a partially related link too, so I put both of them here. If you have library code, and the users of your library run one of your functions at compile time, later if you change your function it may not run at compile time any more. So isn't the quality of being able to run at compile time part of the signature of the function? --- GCC 4.6 implements the C++0x constexpr. I've found a note about constexpr, that touches the topic of logic const too, purity, memoization: http://stackoverflow.com/questions/4748083/when-should-you-use-constexpr-capability-in-c0x/4750253#4750253 Bye, bearophile constexpr is a primitive utility comparing to D, and why it is designed the way it is in C++ is IMO nothing but to maintain backwards compatibility, not because it has anything over what we have here. enum ctfe = fun(); If "fun" no longer ctfe'able compiler will output and error and that is all we need. Why would a library designer care if his code will be executed at compile or runtime? No reason i can think of.
Re: constexpr and CTFE
bearophile wrote: > This first question is mostly for D.learn, but below I show a partially > related link too, so I put both of them here. > > If you have library code, and the users of your library run one of your > functions at compile time, later if you change your function it may not > run at compile time any more. So isn't the quality of being able to run at > compile time part of the signature of the function? An attribute similar to pure that can be checked by the compiler might be useful. However, the signature affects the type right? I'm not sure that is the intent of ctfe. A simple ddoc annotation and a unittest is probably enough to both ensure and convey the ctfe-ability. > --- > > GCC 4.6 implements the C++0x constexpr. I've found a note about constexpr, > that touches the topic of logic const too, purity, memoization: > > http://stackoverflow.com/questions/4748083/when-should-you-use-constexpr- capability-in-c0x/4750253#4750253 > > Bye, > bearophile
constexpr and CTFE
This first question is mostly for D.learn, but below I show a partially related link too, so I put both of them here. If you have library code, and the users of your library run one of your functions at compile time, later if you change your function it may not run at compile time any more. So isn't the quality of being able to run at compile time part of the signature of the function? --- GCC 4.6 implements the C++0x constexpr. I've found a note about constexpr, that touches the topic of logic const too, purity, memoization: http://stackoverflow.com/questions/4748083/when-should-you-use-constexpr-capability-in-c0x/4750253#4750253 Bye, bearophile
