I never liked the original D in the early 2000s, especially the anti-C++ marketing rhetorics. But the post-alexandrescu D is amazing. Just last week I placed a delegate bound to a closure into an immutable struct within a child thread's run function and passed it into the main thread via send to be called and it actually worked! What an amazing language. There aren't many 3rd party libraries, though. And whatever exists is highly questionable.