I was intrigued by Neil Deakin's recent post where he says that when he was a young user, he got mad about all kinds of things that, after a few years as an implementor, he didn't feel mad about anymore....

As I mentioned earlier, when you try to use a JScript .NET array when a CLR array is expected, we create a copy. But when you go the other way, things are a little different. Rather than producing a copy, using a CLR array as a JScript .NET array "wraps it up". No copy is made. The operation is therefore efficient and preserves identity. Changes made to a wrapped array are preserved...

I'm going to take a quick intermission from talking about the type system, but we'll pick it up again soon. I've been thinking a lot lately about philosophical and practical issues of thin client vs. rich client development....

JScript .NET arrays and hard-typed CLR arrays work together, but because these two kinds of arrays are so different they do not work together perfectly. The problem is essentially that JScript .NET arrays are much more dynamic than CLR arrays. JScript .NET arrays can change size, can have elements of any type, and so on. ...

As I was saying the other day, CLR arrays and JScript arrays are totally different beasts. It is hard to imagine two things being so different and yet both called the same thing. Why did the CLR designers and the JScript designers start with the same desire -- create an array system -- and come up with completely different implementations? ...

JScript arrays are sparse, variable-sized, single-dimensional, soft-typed associative arrays. CLR arrays are the opposite in every way! They are dense, fixed-size, multi-dimensional, hard-typed nonassociative arrays. It is hard to imagine two more different data structures with the same name. Making them interoperate at all was a pain in the rear, believe me. ...

A reader asks "can you explain the logic that a string is not always a String but a regexp is always a RegExp? What is the recommended way of determining if a value is a string?"...

In today's installment, things get complicated....

I'm going to make a rare departure from technical stuff for a moment. I've seen Matrix Revolutions twice in the last twelve hours, once in IMAX....

I thought I might spend a few days talking about the JScript and JScript .NET type systems, starting with some introductory material. There is a lot of terminology associated with type systems. What exactly is weak typing? What is a subtype? Just what is a type anyway? These terms are often bandied about and seldom actually defined precisely.

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As I promised, more information on why eval is evil. (We once considered having T-shirts printed up that said "Eval is evil!" on one side and "Script happens!" on the other, but the PM's never managed to tear themselves away from their web browsing long enough to order them.)...

Once upon a time I was in high school. Ah, the halcyon days of my youth....

In the majority of cases, eval is used like a sledgehammer swatting a fly -- it gets the job done, but with too much power. It's slow, it's unwieldy, and tends to magnify the damage when you make a mistake. Please spread the word far and wide: if you are considering using eval then there is probably a better way. Think hard before you use eval. ...