On 5/8/07, Gregory Dai <gregory.dai@gmail.com> wrote:
On 5/8/07, Dan Day <coolmandan@gmail.com> wrote:
On 5/8/07, Mathias Gaunard wrote:
Dean Michael Berris wrote:
I still think the semantics of `lexical_cast("127")` should allow for the conversion to happen -- either convert to a 'short int' then assign to a char, if that makes any sense.
There is no way to distinguish int8_t and char. They are both aliases to the same type. Welcome to the wonderful world of typedefs.
Maybe I'm just short-sighted, but it seems to me this really isn't a problem. A lexical_cast conversion from char * -> char doesn't make much practical sense in my mind except for grabbing the first character in the
Agreed. This is the same behavior as the std::iostreams do, as had been pointed out by a number of people already. Let's leave it at that.
I don't see why we should leave it at that though. Considering the semantics of using static_cast<char>(1) -- unless there's something wrong with that statement inherently -- the casting type shouldn't complain that "hey, you're trying to cast an int to a character... this shouldn't work!" but obviously the user definitely wants to do that otherwise the user would've done it another way.
string, which can be done numerous other ways. AFAICS, lexical_cast could be
specialized for char * -> char for such conversions as the OP desires. To me, that would be far more useful than the current behavior.
Nope, it's tempting to do "nice" thing, but again let's leave it at that (see above), and close the subject.
If the argument is just because the standard streams treat it that way, doesn't mean that we should stick to that when obviously a lexical_cast<T> implies that you want to convert a string / const char * to a numeric value of the type T. I particularly don't see why the constraint that the standard streams imposes in this case should affect the behavior and/or semantics of lexical_cast<T> -- because if I really for instance wanted to use a standard stream (which has completely different semantics from lexical_cast<T>) then I would have used that. Being that lexical_cast<T> uses a standard stream underneath the hood should be an implementation detail, and should not concern the users of lexical_cast<T> who actually expect to have a string converted to a numeric value of type T -- granted that T is a numeric type. -- Dean Michael C. Berris http://cplusplus-soup.blogspot.com/ mikhailberis AT gmail DOT com +63 928 7291459