Dr. Blip's PC-Doctor Blog

The next C++ standard (C++0x) will have lambda expressions as part of the standard. N2550 introduces them. It's a short document, and it's not too painful to read. Go ahead and click it.

Like many new C++ standards, it's not clear yet how the new feature is going to be used. Michael Feathers has already decided not to use them. At least one other person seems to mostly agree. I, on the other hand, am with Herb Sutter who seems excited enough about the feature to imply that MSVC10 will have support for it. This is going to be a great feature. Incidentally, Sutter has mentioned an addition to C++/CLI in the past that would add less sophisticated lambda support for concurrency. I suspect he's serious about adding the support soon.

There have been many times when I've desperately wanted to avoid defining a one-off functor or function in my code. In fact, there have been times when I've been desperate enough to actually use Boost.Lambda! This standard is a clear win over Boost's attempts to deal with the limitations of C++03.

Continue reading "C++0x: The Lambda Expression Debate" »

ECMAScript 4.0 (ES4) is on its way. This will be the next standard for JavaScript. It's not going to be usable on web pages for a while, though. In fact, I suspect I won't be using it on my web page for at least 5 years. The problem is simple: as long as people still use older browsers, you won't be able to assume that people have it.

However, the features in it are an interesting look at what the standards committee thinks is wrong with the current JavaScript. This is not a minor patch release. This is a dramatically overhaul of the current JavaScript (ES3). Oh, they've included a lot of minor things that are simply broken in ES3. These changes are certainly interesting, but today I'm going to talk about their major focus. They want to make it easier to develop large applications in JavaScript. Clearly, they understand that people are starting to develop large applications for web browsers, and they feel that there are problems with the currently available technologies for this.

I don't have any experience with developing what I'd call a large JavaScript application, but we are starting to develop an extension of PC-Doctor for Windows that uses JavaScript in numerous places to control its behavior. In my dreams, I imagine that it will eventually become a large application made up of plugins that run on JavaScript.

Let's go through the major features that the committee thinks I'll need as our technology gets bigger...

Continue reading "The Next JavaScript..." »

This article is going to have more questions in it than answers. It's about a problem in software development that I'm not sure I've worried about enough. I've certainly thought about it for specific cases, but this is the first time I've tried to think about the problem in general.

My main question revolves around the cost of complexity in software. There is certainly a large cost in making software more complex. Maintenance becomes more difficult. Teaching new employees about the project becomes harder. In the end, you will get fewer engineers who understand a complex project than a simple one.

Unfortunately, almost any non-refactoring work will add to the complexity of a project. However, some changes can have a large effect on the complexity in a short period of time. Adding a new library or technique to the code base, for example, will make it so that the new technology will have to be understood by people working on the project.

What I really want to know is how much can this cost of complexity be mitigated? Besides switching libraries to add, what can be done to decrease the cost? My question is based on the assumption that some complexity is essential. So, given that you're going to add a new library to the code base, for example, what can be done to reduce the cost?

Continue reading "The Cost of Complexity" »

The visitor pattern from the GoF is frequently overlooked by programmers who are used to object oriented programming. However, in some cases, it is significantly cleaner and easier to use than an overridden function. Unfortunately, it's easier to misuse as well, and, when it is used poorly, it can be a real mess.

I was going to tell you about my static analysis project and how I'm using the visitor pattern there. Then I took a glance at the wikipedia article on the visitor pattern. It's clearly written by a OOP fanatic who's never seen the alternatives, so I'm going to contrast my implementation of visitor with the one there.

The contrast is useful because wikipedia's implementation is written using object oriented principles. Part of my goal with this post is to explain about OO alternatives. My implementation is written using compile time polymorphism rather than runtime polymorphism. As we'll see, this is significantly prettier and more flexible than runtime polymorphism.

Continue reading "The Visitor Pattern as an Alternative to OOP" »