12 Jun
2015
12 Jun
'15
12:45 a.m.
On 6/12/15 3:39 AM, Louis Dionne wrote:
Instead, in a heterogeneous setting, you probably want it to return false_. With Fusion/MPL, this is not a problem because they use `std::is_same` to perform comparisons. However, `std::is_same` performs a very shallow comparison and only allows comparing types. Instead, Hana uses a more general system which also allows comparing values, but we have to return false_ for unrelated objects, a bit like `std::is_same` returns `std::false_type` on unrelated types.
I might not be understanding this correctly, but Fusion == does not use std::is_same. It does value comparison much like tuples. Regards, -- Joel de Guzman http://www.ciere.com http://boost-spirit.com http://www.cycfi.com/