On Tue, Jun 5, 2012 at 10:26 AM, John Maddock <boost.regex@virgin.net>wrote:
Also just realized that while a simple adapter backend:
template <class BigInteger> class exact_float;
Would be more or less trivial as far as the arithmetic goes, other stuff like string conversion would be *much* more complex, exactly which conversions and/or string formatting should be supported would require some careful thought.
Yes, agreed regarding the trickiness of string conversions :( I guess if one doesn't want or need to implement such facilities, one could just throw on such overloads.
Actually, one could see it as a weakness of the library that so many of the requirements are compulsory and not optional.
Actually, there isn't a huge list of compulsory requirements, and even then the term "compulsory" might need revising - maybe more like "non-synthesizable". So if you want all of mp_number's documented operations to work, then you need to implement all of the "non-synthesizable" requirements. However, for a type like a ring, you wouldn't implement eval_divide even though it's one of the "compulsory" requirements - the result would be that the divide operator for mp_number<my_ring> wouldn't instantiate, but everything else you've implemented would. John.