On Sun, Sep 16, 2012 at 6:27 PM, Dave Abrahams <dave@boostpro.com> wrote:
on Tue Sep 04 2012, Lorenzo Caminiti <lorcaminiti-AT-gmail.com> wrote:
Just to consider all alternatives, we could also do this:
CONTRACT_FUNCTION( template( typename To, typename From ) if( // used with enable_if in the declaration part is_convertible<From, To>::value, is_convertible<To, From>::value )
+1 for "if." Andrzej's "enable_if" suggestion is nice and more explicit too, but there's no syntax highlighting bonus. I'm torn.
requires( // included in the function body
The fact that this is "included in the function body" is irrelevant I think. I guess the real point you're trying to make is that it generates hard errors at acompile time when violated. That suggests something like "asserts" instead of "requires."
Then I think "check" for hard errors and "requires" for SFINAE is a good choice (requires better than if or enable_if for SFINAE I think...). I will read N3351 and check again with this ML before making a final decision: http://sourceforge.net/apps/trac/contractpp/ticket/96
static_assert(sizeof(To) >= sizeof(From), "destination too small"), boost::Copyable<From> ) (To*) memcopy ( (To*) to, (From*) from ) precondition( to; // pointer not null from; // pointer not null ) ) { // ... }
Thanks, --Lorenzo