Yuval Ronen wrote:
#define MY_STRUCT_AS_TUPLE(obj) const_tie(obj.x, obj.y, obj.z)
bool operator<(const MyStruct &lhs, const MyStruct &rhs) { return MY_STRUCT_AS_TUPLE(lhs) < MY_STRUCT_AS_TUPLE(rhs); }
Nobody corrected me, but this code works just fine with the existing boost::tie. There's no need for const_tie. I even prepared a macro to ease the creation of comparison operators: #define IMPLEMENT_COMPARISON_OPERATOR(TYPE, MAKE_COMPARABLE_MACRO, OPERATOR) \ bool operator OPERATOR(const TYPE &a_lhs, const TYPE &a_rhs) \ { \ return MAKE_COMPARABLE_MACRO(a_lhs) OPERATOR MAKE_COMPARABLE_MACRO(a_rhs); \ } which I can use as (if I have a struct by the name MyStruct): #define MY_STRUCT_AS_TUPLE(obj) tie(obj.x, obj.y, obj.z) IMPLEMENT_COMPARISON_OPERATOR(MyStruct, MY_STRUCT_AS_TUPLE, ==) IMPLEMENT_COMPARISON_OPERATOR(MyStruct, MY_STRUCT_AS_TUPLE, <) I think this is a very convenient way of creating comparison operators, if anyone is interested, and maybe it will even be a good idea to add it to the tuples documentation as "possible usages". Hope it was useful, Yuval