Today, yet another episode in my ongoing series " What's the difference? " This time, a non-computer-related topic . I am often complimented on my choice of outerwear in the Seattle rainy season, and I hate to respond to a well-meant compliment with a...

Last time I noted that any two usages of "the same" anonymous type within an assembly actually unify to be the same type. By "the same" we mean that the two anonymous types have the same property names and types, and that they appear in the same order...

Back in my last post of 2010 I said that I would do an example of anonymous types unifying within an assembly "in the new year". I meant 2011, but here we are "in the new year" again, so, no time like the present. The C# specification guarantees you that...

If you ask a dozen C# developers what a "local variable" is, you might get a dozen different answers. A common answer is of course that a local is "a storage location on the stack". But that is describing a local in terms of its implementation details;...

Here's an inconvenient truth: just about every "public surface area" change you make to your code is a potential breaking change. First off, I should clarify what I mean by a "breaking change" for the purposes of this article. If you provide a component...

Happy New Year all! It has just been brought to my attention that this blog and the Programmer Ryan Gosling photo blog share at least one reader: I admit it, I LOL'd. In the interests of total accuracy I'd like to point out that the first entry on the...

OK, let's finish up this year and this series. We have an algorithm that can compute what cells in the zero octant are in view to a viewer at the origin when given a function that determines whether a given cell is opaque or transparent. It marks the...

I hope you all had a pleasant Christmas and Boxing Day; we chose to not travel to see family this year and had a delightful time visiting friends. We'll finish up 2011 here with a bit more on shadowcasting, and then pick up with more C# language design...

Last time we saw how many different ways there were to get the calculation of the top cell based on the top vector wrong. Today we'll take a briefer look at determining the bottom cell. We know from our discussion of last time that the right way to determine...

Before we get started, thanks for all the great comments to the previous couple of posts. I'll be updating the algorithm to try to make even better-looking circles of light based on the comments. Like I said, there's a lot of subtleties to these algorithms...

I hope the basic idea of the shadow casting algorithm is now clear. Let's start to implement the thing. There are two main concerns to deal with. The easy one is "what should the interface to the computation look like?" The second is "how to implement...

I've always loved the "roguelike" games; perhaps you've played some of them. Those are the games where you get a top-down view of a tile-based world, and have as much real time as you like to make a choice of action. The canonical plot is to enter a dungeon...

No technology today. Rather, some advice. I don't know if there's some sort of grifter convention going on, but I have seen four different short-con artists operating in Wallingford, the neighbourhood of Seattle where I live, in the last three days. Though...

In my earlier article from April 2011 on interface implementation I noted that C# supports a seldom-used feature called "interface re-implementation". This feature is useful when you need it but unfortunately is one of those features that can bite you...

Today, another episode of my ongoing series " What's the difference? " Today, what's the difference between a remainder and a modulus, and which, if either, does the % operator represent in C#? A powerful idea that you see come up in mathematics...

Last time I discussed why it is that we have all the .NET compilers target an "intermediate language", or "IL", and then have jitters that translate IL to machine code: because doing so ultimately reduces the costs of building a multi-language, multi...

One of the earliest and most frequently-asked questions we got when we announced the Roslyn project was "is this like LLVM for .NET?" No, Roslyn is not anything like LLVM for .NET. LLVM stands for Low-Level Virtual Machine ; as I understand it (admittedly...

Just a couple of quick links today. First: One of the questions I get most frequently is " can you recommend some good books about learning to program better in C#? " The question is usually asked by a developer; the other day I was surprised to get...

Before I get into the subject of today's post, thanks so much to all of you who have given us great feedback on the Roslyn CTP. Please keep it coming . I'm definitely going to do some articles on Roslyn in the future; the past few weeks I have been too...

I am super excited to announce that the Roslyn project code is now sufficiently coherent that we can start showing it to customers! But I am getting ahead of myself somewhat. What is this "Roslyn" project? Here's the deal. We've got these great...

I've never owned an Apple product; I haven't written Mac software professionally since working on the Mac version of Visual Basic briefly in 1994. Nevertheless, Steve Jobs inspired me every day . Wanting to make "insanely great" technology is one thing...

I am pleased to announce that MSDN Magazine is doing a special issue this month on the new "async-await" feature that we are working on for the next versions of C# and Visual Basic. If this subject interests you, see my introductory article for beginners...

A lot of people really love the idea of cryptography. To computer geeks like us there is nothing cooler than the idea that computing relatively simple arithmetic on a message can enable you to communicate secretly with anyone in the world, even if there...

(Note: Not to be confused with Representation and Identity ) Here's a question I got this morning: class Alpha<X> where X : class {} class Bravo<T, U> where T : class where U : T { Alpha<U> alpha; } This gives a compilation error stating...

Well that was entirely predictable; as I said last time , if you ask ten developers for a definition of "type", you get ten different answers. The comments to the previous article make for fascinating reading! Here's my attempt at describing what ...