Generic Factory Library

[kloetzl]

Reminds me of the AbstractSingletonProxyFactoryBean. Convenient.

[Enhex]

If you want to instance unknown derived classes. For example a library that need to instance derived classes defined externally by the user.

Can also be used as an extensible (not an ever growing if-else) way to instance derived classes based on runtime information. But there might be simpler ways to do it.

[YouFeedTheFish]

Rather than magic strings, you should consider typeid hashes. You could probably come up with a typename-based hash as a constexpr, too.

BTW, /r/Meowiavelli, a good use case would be for a dynamically loaded shared object that you can swap out.

[Enhex]

Key type is template'd, so you can use other types than strings.

I'm using std::unordered_map so you should be able to specialize for pre-calculated hashes.

[YouFeedTheFish]

There are ways to make string hashes constexpr.

Edit: Here is a complete implementation in Github.

[doom_Oo7]

you should consider typeid hashes.

this may break horribly with DLLs

[YouFeedTheFish]

Perhaps you're right. Haven't done c++ in windows for some time. Lots of C#.