defining "in" What is the proper way in D2?

[bearophile]

Timon Gehr:

> AAs are built-in. The optimization you describe is quite easily carried 
> out by the compiler. And I am quite sure that in the long run, it will 
> bite us.

With the LDC compiler if you perform an AA lookup, and after one or few lines you do it again, (because you are using an if and you are not using the pointer nature of the return value of "in AA"), LDC most times uses a single AA lookup.

This little group of optimizations were added to LDC just to improve AA usage. With such simple optimizations I think 99% of times you don't need "in AA" to return a pointer. So probably returning a bool is enough. I don't think I have ever stored the return pointer of "in AA", I have used it locally, just to save one AA lookup.

Bye,
bearophile