Including iostream means introducing the static (global) constructors
and destructors for std::cin, std::cerr, and std::cout. That extra
init and fini code is undesirable when those streams are not actually
used.
Instead, we'll use the narrower includes for exactly what's needed,
i.e., <istream> or <ostream>.
Since `std::string` has to be dynamically constructed and destructed,
it could be accessed before initialization or after destruction in a
multithreaded context. By using constant c-strings instead, we guarantee
that the array will be valid for the whole lifetime of the program. The
use of `constexpr` also enforces this requirement.
I have run clang-format on the file to format my changes according to
CONTRIBUTING.md.
* Add compilation flags: -Wshadow -Weffc++ -pedantic -pedantic-errors
* Delete implicit copy & move constructors & assignment operators
in classes with pointer data members.
* An exception to the above: Add default copy & move constructors &
assignment operators for the Binary class.
* Convert boolean RegEx operators to binary operators.
* Initialize all members in all classes in ctors.
* Let default ctor delegate to the converting ctor in
Binary and RegEx
* Don't change any tests except regex_test (as a result of the change
to binary operators).
Note: https://bugzilla.redhat.com/show_bug.cgi?id=1544675 makes
-Weffc++ report a false positive in "include/yaml-cpp/node/impl.h".
