Anton Bukov has done a great job replicating the LINQ framework in the Foundation collections classes.
For those of you who aren’t former .Net fanboys, LINQ is the gem of .Net development. LINQ stands for Language-Integrated Query and it is a compile time, source-independent querying language for .Net. You can query in-memory arrays, SQL databases, or Amazon’s API with the same compile-checked querying language. It’s awesome.
I actually miss it and, even though blocks made a lot of headway in Objective-C since 2010, the Foundation collections classes still lag behind .Nets in querying. I’m really glad to see progress being made on this.