Hello, for the integer wraps used for flags I have a third proposition, a working example is attached: * "enum class DisplayOption" for the individual flags * "class DisplayOptions" with an implicit converter DisplayOption -> DisplayOptions So we get an enum for the single options and avoid the old enum-style.
Diether
#include <iostream>
enum class DisplayOption {
SHOW_HEADING = 1 << 0,
SHOW_DAY_NAMES = 1 << 1,
NO_MONTH_CHANGE = 1 << 2,
SHOW_WEEK_NUMBERS = 1 << 3,
SHOW_DETAILS = 1 << 5
};
class DisplayOptions {
friend DisplayOptions operator|(DisplayOption, DisplayOption);
public:
DisplayOptions() = default;
DisplayOptions(DisplayOption v)
: value(static_cast<int>(v))
{ }
operator bool()
{ return value != 0; }
DisplayOptions operator&(DisplayOption rhs) const
{
if (value & static_cast<int>(rhs))
return rhs;
else
return {};
}
DisplayOptions& operator|=(DisplayOption rhs)
{
value |= static_cast<int>(rhs);
return *this;
}
private:
int value = 0;
};
DisplayOptions operator|(DisplayOption lhs, DisplayOption rhs)
{
DisplayOptions res(lhs);
res.value |= static_cast<int>(rhs);
return res;
}
/*
*/
void write(DisplayOptions o)
{
if (!o)
std::cout << "none\n";
if (o) {
if (o & DisplayOption::SHOW_HEADING)
std::cout << "show heading\n";
if (o & DisplayOption::SHOW_DAY_NAMES)
std::cout << "show day names\n";
if (o & DisplayOption::NO_MONTH_CHANGE)
std::cout << "no month names\n";
if (o & DisplayOption::SHOW_WEEK_NUMBERS)
std::cout << "show week numbers\n";
if (o & DisplayOption::SHOW_DETAILS)
std::cout << "show details\n";
}
std::cout << "\n";
}
/*
*/
int
main()
{
auto x = DisplayOption::SHOW_HEADING;
write(x);
write(x | DisplayOption::SHOW_DETAILS);
// not possible: x |= DisplayOption::SHOW_DETAILS
auto y = DisplayOptions(DisplayOption::SHOW_DAY_NAMES);
y |= DisplayOption::SHOW_DETAILS;
write(y);
return 0;
}
pgp5TMaz1rg3t.pgp
Description: Digitale Signatur von OpenPGP
_______________________________________________ gtkmm-list mailing list gtkmm-list@gnome.org https://mail.gnome.org/mailman/listinfo/gtkmm-list
