Missing operator in less_than_comparable2?
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Due to a compilation error, I just had a look at Boost.Operators and think there's an inconcistency in less_than_comparable2.
From my understand, it should generate:
operator<=(T, U)operator>=(T, U)operator> (T, U)operator< (U, T)operator<=(U, T)operator>=(U, T)operator> (U, T)
based on the user-supplied operator<(T, U) - aka extend less_than_comparable1 for two types (1), but operator>(T, U) is actually missing in less_than_comparable2.
Is this a bug or a deliberate design?
(1) Note that equality_comparable2 exhibits exactly that behavior compared to equality_comparable1.
less_than_comparable2 requires T<U and T>U to be supplied by the user, as the latter can not simply be derived from the former. Reversing the arguments of T<U yields U<T and T<U does not necessarily allow that. Even if it would work, it would probably convert the arguments from T to U and from U to T.
The operators library generates new operators based on existing one by only allowing to swap the existing arguments or negate the result of another comparison. This is not the case here.