I’m a bit worried things are getting far too samey here. This past week I spent a day fixing up a client’s buggy iPhone app and then another day working on another client’s PHP+JS property database. I also managed to get time to make some progress on an interesting client app that I’m not going to talk about in detail.

Well, that’s how I started writing this blog post a week ago, and then other activities took over and dragged me away. I attended OGGCamp over the weekend which was really interesting but did take up plenty of time. I’ll continue below and hopefully get week 93’s post out a lot sooner!

During the last week I did tweet a few times about chess moves so I’ll now admit that the interesting client iPhone app is based around chess. Obviously the rules of chess lead to some very interesting challenges while coding. For instance I had expected that validating moves was going to be very difficult to do. I think this was because I imagined taking a piece and a starting square and having to figure out all the places that it can go to. While this isn’t overly difficult it could be fiddly and time consuming.

In actuality when it came down to it I found it wasn’t so hard. In my situation I have a starting square and a destination square and need to figure out if it’s valid for a given piece. This is actually much easier, or at least was much easier for my brain to work out.

For instance with a knight, even though they have a funny way of travelling all you have to check is that they’ve travelled 2 squares sideways and 1 up or down, or vice versa, anything else is wrong. I also made sure that before doing custom moves per-piece I also did some basic sanity tests like making sure the starting square and destination were within the board and that the destination square didn’t contain a piece of the same colour.

I’ve included a screenshot above to liven this post up but it doesn’t really show what the app does, in fact the app doesn’t do very much at the moment. I’ve been very careful to keep my code very modular so I’m actually hoping to use it in a number of apps, or at least do an iPhone and iPad version of the main app. For a lot of the code I’ve even been trying to stick to pure C rather than Objective-C as I believe that will help me if I try porting this to Android.

Unfortunately I’ve had to put this app down again while working on another project this week which I’ll mention in the next post but I’m hoping to get back to the chess app again soon so that I can get it finished off and delivered to the client. I promise my next post will come a lot sooner, I’m already writing it in my head!