Friday, February 10, 2006

Generics at user meeting

I went to the Indianapolis .Net User Group meeting last night. They advertised Generics as the topic, and since I really didn't know anything about them, I was looking forward to it.

It turned out to be more interesting as a group dynamic than as a presentation. As a presentation, what I gleaned was that, from a user's perspective, generics are precisely identical to C++ templates. You declare a variable of a type that takes generics, and drop the specific type after the type name, in brackets: ArrayList foo = new ArrayList. Or you declare your own class and declare a after it to create your own generic.

From an implementer's standpoint, they're pretty darn different from C++ templates, as you might expect. And working out exactly what those differences might be engendered more discussion from the group than any topic I've yet seen. People were interested in how they were implemented, whether they would really avoid boxing, whether it was done at run time or compile time. There appeared to be two or three people who really knew their stuff, too - they were discussing what the IL that was generated looked like and that sort of thing. By the 45 minute mark, I was pretty sure that I was in for a two-hour or more night.

But amazingly, the entire presentation couldn't have been more than 35 minutes. Add in 25 minutes of discussion and the whole thing would have been over with before seven with plenty of time to draw door prizes and be out of there by 7:30.

But I don't know if that's what happened or not. The Q&A period was still going strong at 7:05 and I decided to bail. I hope my ticket didn't win a new car or something :)