AMDG
I vote to ACCEPT PFR into Boost.
global_ops.hpp/ops.hpp/functions_for.hpp:
- Defining functions in a header as static risks UB via the
one definition rule.
- Can the operators be constexpr?
- I don't think that global_ops.hpp is a good idea.
`using namespace boost::pfr::ops` in the global namespace achieves
almost the same effect and is more clear.
- `using namespace boost::pfr::ops` is also quite fragile. It
will effectively declare the operators in the global namespace
The nearest namespace that encloses both the current scope and
the boost::pfr::ops). This means that they will be hidden by
any operators defined in the current namespace. For this reason,
`using boost::pfr::ops::specific operator` is generally more
reliable for functions like comparison operators that tend to be
heavily overloaded.
#include
namespace ns {
struct X {};
// Uncommenting this causes a compile error
// bool operator<(X, X) { return false; }
struct Y {};
void test() {
Y y;
using namespace boost::pfr::ops;
y < y;
}
}
- Does the documentation specify anywhere what operators the
struct members need to define in order for the precise operators
to work? It looks like the comparison operators require operator==
and the operator being defined.
- Would it make sense to define operator<=> for C++20?
- It would be nice if there were a way to select operators
more specifically for BOOST_PFR_FUNCTIONS_FOR. What if I
only want the comparision operators and hash, and want to
define my own stream operators?
- How would I define operators for a class template?
detail/fields_count.hpp:
- Do ubiq_lref_constructor and ubiq_rref_constructor need to have
their conversion operators defined? If they were only declared
they wouldn't need to use unsafe_declval.
-----------------
- The error when a struct has an array member is not very informative.
I can't think of a good way to detect this, however.
- It would also be nice if there were a trait that covers
all the detectable modes of failure, or perhaps a macro that
has all the static asserts in fields_count.
- The reference docs often uses it's instead of its:
its = possessive pronoun
it's = contraction of it is
In Christ,
Steven Watanabe
