davedolan.com

Ok, well I was so anxious to hear about the DLR, that I forgot to look around for articles on it. I missed this one [The One True Object (Part One)] by a month.

And this one [First DLR Talk On The Web - Live (pre-recorded!)].

And, wow, I was really sleeping folks, because this one [A Dynamic Runtime DLR] is even days older than those two.

I’m not just a link poster, honest. I do a lot of writing too, it’s just that I’m most definitely not an expert on this subject, even though I’m trying here. I’m so happy stuff is finally coming out, but I just don’t have all day to play like I wish I did, so I have to rely on blogisms (which I have to admit, coming straight from the library authors’ desk is great,) but I have a feeling they’re saving the best for a book or something. Oh yeah, and they’re probably coding. Go figure.

I’m not so sure that I would be able to work under those conditions. Picture yourself in this scenario: It’s like the world is watching with ticking stop watches, just waiting for you to stop reading that google, I mean… er… msn.. news article. “Check your email later, man, we’re waiting for the DLR with examples and doco!!!” Yeah. See?

So my hats off to Jim for taking the time to write about this. Whatever happened to that John Lam cat? Oh yeah, he’s a rock star now! (In all seriousness, I’d probably live in a hole if I were hired off to Microsoft on such a high profile project.)

In my own various attempts to write a ‘dynamic’ language of my own, I’ve always tried to do what the folks do in C++ land.. they make tagged unions or wrappers for data types and objects, and then have some sort of syntax tree for dealing with the cases of each… Even take a look at our friend TreeCC, which is, at least for it’s day, one of the most excellent tools for generating AST nodes en mass (though not necessarily for dynamic languages, but just anyway for argument) it even does the tagged union thing. So naturally I hadn’t even considered the possibility that building actual CLR types (a la the one true object) in .NET meta-data and IL is the way to go… I just figured I ought to write my own ‘runtime support’ which I figured must include a type system that marshals to the real type system. Hah. This is where I learned a valuable lesson. “Look at the source to IronPython.”

In particular, I’d take a look at the illustration in UserTypes.cs. The one comment that sticks out nice and blonde at a brunette convention:

“UserType represents the type of new-style Python classes (which can inherit from built-in types). ”

Who would have thought that some of the most interesting information in a comment would be the aside in parenthesis?