I was also worried about @ but it feels OK after some time. What I really like is the new delta notation. Makes for far more concise but still readable aggregat

I was also worried about @ but it feels OK after some time. What I really like is the new delta notation. Makes for far more concise but still readable aggregate handling. For once, going in the right direction for readability. Plus, it helps expressing intent and removed some proof burden ("yes I'm passing a whole structure but I'll be modifying only field x and y").