51–60 of 160 posts
This is a typical example of a solution to an artificial, self-imposed problem created by C++'s assumptions. As a programmer, I would feel frustrated to have to figure this out instead of spending time on something a user would actually care about.
I like it! The self-documentation of where the call is coming-from is quite nice (though a more descriptive name like CallFrom would make that even clearer, were it the principle intent). I can't help myself, though: template Badge FakeBadge() { struct Stub {} return reinterpret_cast >(Stub()); }
template
Badge FakeBadge() {
static struct Stub {} stub;
return *(Badge*)&stub;
};I like it! The self-documentation of where the call is coming-from is quite nice (though a more descriptive name like CallFrom would make that even clearer, were it the principle intent). I can't help myself, though: template Badge FakeBadge() { struct Stub {} return reinterpret_cast >(Stub()); }
Doesn't subvert Device badges for me. Complete sample: template class Badge { friend T; Badge() {} }; template Badge FakeBadge() { struct Stub {}; return reinterpret_cast >(Stub()); }; class Device { public: static Badge getBadge() { return Badge (); } }; void needDeviceBadge(Badge badge) { } int main() { needDeviceBadge(Device::getBadge()); // no error needDeviceBadge(FakeBadge ()); // error! return 0; } g++ errors:…
Wouldn't -Wextra yell about the Badge being an unused parameter in the register devices? You would have to do some kind of dummy call that the compiler would have to optimize away.
I like it! The self-documentation of where the call is coming-from is quite nice (though a more descriptive name like CallFrom would make that even clearer, were it the principle intent). I can't help myself, though: template Badge FakeBadge() { struct Stub {} return reinterpret_cast >(Stub()); }
Doesn't subvert Device badges for me. Complete sample: template class Badge { friend T; Badge() {} }; template Badge FakeBadge() { struct Stub {}; return reinterpret_cast >(Stub()); }; class Device { public: static Badge getBadge() { return Badge (); } }; void needDeviceBadge(Badge badge) { } int main() { needDeviceBadge(Device::getBadge()); // no error needDeviceBadge(FakeBadge ()); // error! return 0; } g++ errors:…
Could you make the badge the last argument and give it a default value, so you don't need the initialization at the function call? It looks a bit strange and would need an explanation for why the empty initialization list is there IMO. I'm not sure if it would work, cppreference has this to say about default arguments: > The names used in the default arguments are looked up, checked for accessibility, and bound at th…
Could you make the badge the last argument and give it a default value, so you don't need the initialization at the function call? It looks a bit strange and would need an explanation for why the empty initialization list is there IMO. I'm not sure if it would work, cppreference has this to say about default arguments: > The names used in the default arguments are looked up, checked for accessibility, and bound at th…
Unfortunately it seems like default arguments can't use private constructors. Both GCC and Clang immediately fail at the declaration. Not fair, C++!
/home/andreas/src/serenity/Kernel/FileSystem/VirtualFileSystem.h:81:52: error: 'Badge::Badge() [with T = Device]' is private within this context
Wouldn't -Wextra yell about the Badge being an unused parameter in the register devices? You would have to do some kind of dummy call that the compiler would have to optimize away.
No warning:
void VFS::register_device(Badge, Device& device) { ... }
void VFS::register_device(Badge badge, Device& device) { ... }I used to carefully design my C++ code with public / private / protected / friend (and the pointer-to-impl pattern for "compile time private") but a few years ago I started doing everything all-public ala python (struct instead of class by default) with occasionally an m_ prefix for "intended to be private", and I've never looked back. It's been great, made my programming life much easier. This badge thing is clever,…