alt Hacker NewsC++ conference speakers (including keynotes) are now begging everyone to stop using enum to string in their example. While they are a simple and easy to understand example, reflection is for much more interesting problems. I can't think of any other example that I would type into a comment box or put on a slide.
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Serialization is the canonical example. Being able to turn
struct MyStruct {
int val = 42;
string name = "my name";
};
{
"val": 42, // if JSON had integers, and comments of course
"name": "my name",
}
Anybody the derive traits rust has are a good demo.
I mean a readable implementation of tuple with minimal overhead is a great case for me (went from around 1.6k lines to approximately 250 lines). I wrote an implementation including the normally difficult to implement tuple_cat based on c++26 within a few hours.
My favorite thing is that I will get to remove and replace most of the cryptic template recursion stuff I have with "template for" and maybe a bit of reflection. Debugging the unrolled stuff will be a joy in comparison.
It comes up pretty frequently in java. Serialization/Deserialization, adding capabilities based on type, Adding new capabilities to a type, general tuning (for example, adding a timing or logging call onto methods).
Almost all the Java web frameworks are giant balls of reflection. Name a function the right way or add the right magic annotation and the framework will autowire it correctly.
It's a pretty powerful tool. (IDK if C++'s reflection is as capable, but this is what was enabled by java's reflection).