Monthly Archives: March 2009

Studying For 70-505

Now that I’ve passed the base .NET exam (70-536), I’m working on the Windows Forms development certification exam.  Passing that will get me the “MCTS: .NET Framework 3.5, Windows Forms Applications” cert.  I’m pretty confident that I’ll pass it on the first try.  Here’s why:

1. I’ve written a lot of WinForms programs (including 3 for the Basternae project — the help editor, ANSI screen editor, and the zone editor).

2. The exam recommends one year of experience with the topic rather than the two that 70-536 wanted.

3. The book is better-written than the 70-536 book, is more accurate, and is about 300 pages shorter.  It’s less klunky as a learning tool.

I’ve finished the reading portion of the book already, so all I need to do now is spend some time practicing the parts I don’t know all that well.  Look for an exam results report in about a week or so.

Visual Studio Refactoring And Encapsulation

I love the refactoring support in MS Visual Studio.  It makes certain things like field encapsulation incredibly easy.

For instance, thanks to its origins in C, most of the Basternae 3 codebase doesn’t have encapsulation yet.  This means that there are tons of class member variables declared like this:

public string _keyword;

Setting the _keyword member variable to private and creating a property named Keyword with getters and setters that reference the _keyword variable would take about 30 seconds.

With Visual Studio it’s easier:  Just right-click on the variable and select “Encapsulate Field”.  It will come up with a reasonable property name and automatically generate the code and set the variable to private.

Pretty nice, but nothing to write home about.

But, here’s the magic:

All references to that variable in code are AUTOMATICALLY changed to refer to the property.  If that member variable was used in 50 different places, Visual Studio just saved you the trouble of making 50 different changes or doing a search-and-replace that may or may not get everything on the first try.

Of course, this doesn’t automatically update any XML files that have been saved using the old variable name.  To take care of that you can do one of two things.

1. Do a search and replace in every XML file that your class would have been serialized to and hope you didn’t miss one.
2. Use the XmlElementAttribute on your property to map the saved attributes to your new type:
[XmlElement(“_keyword”)]
public string Keyword
{

#2 is obviously safer and easier, especially since it doesn’t require changes to existing data.  Of course, your data files might be clearer to read if they used the exact property names, but do you want to go through the trouble?  Likely not.

Passed The 70-536 Exam

I took the Microsoft 70-536 .NET certification exam today.  I can’t say it was easy, but I clobbered it.  It wasn’t for lack of preparation either.  I think I may have read just over 2000 pages worth of material.

Studying For 70-536

In a previous life as a network admin, I took all sorts of certification tests — A+, Network+, I-Net+, CNA, and MCP, which I later upgraded to MCSA and then MCSE.

One thing that these tests always required was extensive knowledge of obscure parts of a technology regardless of their usefulness in working with the technology. You have to know all sorts of useless information to officially be an expert.

Since I’m studying for the Microsoft .NET Framework Foundation (70-536) exam, I’ve been investigating the cobwebbed corners of the framework.  It’s amazing how many things there are that I’ve never used, never thought I’d use, and probably never will use.  Even so, I have picked up a few useful tricks in the process.

What doesn’t help is the extensive amount of errata in the thousand-plus-page study guide.  There’s so much broken that there are FOUR knowledge base articles, presumably due to some sort of size limitation in a KB article:

http://support.microsoft.com/kb/923018
http://support.microsoft.com/kb/935218
http://support.microsoft.com/kb/949730
http://support.microsoft.com/kb/949734

Needless to say, I’m not relying too heavily on a single reference book.

The New Client In Action

In working on the new WPF-based client, I’ve redone the way I handle ANSI character code processing. Instead of a horrible multi-hundred-line nested if-statement-monster, I’ve created something based on regular expressions that is about 25 lines or so of code. It’s not absolutely perfect, but it’s already better than what we had with the wxWidgets + SDL client (what I call “Client #2”). (FYI: Client #1 was an SDL-only client that used a ridiculously huge amount of CPU and was unworkable in resolutions above 640×480).

Screenshot:

There’s still plenty more work to do on the client.

No Null Checks

After running the automated tests generated by Pex, it’s amazing how many functions in the old codebase received various class or structure arguments and immediately started working with the data in them without ever checking for null. It was a paradigm followed by the old public code release of Diku, Envy, Merc, etc. and was unthinkingly carried on by the Basternae 2 programmers, myself included. This lack of data validation is being corrected.

It’s no surprise that the old codebase crashed a lot. After seeing the extent of the damage, I feel like I need to go back and revisit the Magma codebase and add a lot of stabilization.

In fact, one of the main things with Basternae 3 that will help stability is the fact that all player-entered commands are executed within a try-catch block. This means that typing in a broken or unsupported command should never crash the MUD, which was a huge problem in the “bad old days”. Instead it will log an error and appear to do absolutely nothing from the player’s viewpoint.

The New Client So Far

It’s just screenshots of windows without anything in them — no fancy colors, images, or any bells and whistles yet.  This is just to show that it really exists:

.NET Basternae Client First Screenshot

C++ Is a Pain in the Arse (New Client)

Yesterday I opened up the source code for the Basternae Client in order to make a few changes, fixes, and updates.  What I had forgotten in the two years since I had been programming C++ actively is what a pain in the behind it is to get anything done in C++.

Sure, you can do anything with it, but there’s so much tedium and overhead involved that it takes forever to get anything done.  Sure, it’s great for low-level code where you’re tossing bits and bytes around, but for user interface development it’s just too unwieldy.

Out of frustration, I sat down and rewrote most of the client in C# in a few hours.  Mind you, it’s not fully implemented, but it’s usable as a telnet client.  I’d say about 8-10 more hours of development time and it’ll be ahead of where the other client was.

That makes this the third version of the client.  The first version was pure SDL with C++.  The second version was SDL combined with wxWidgets.  The third version is C#.NET and WPF.

Another benefit of switching to WPF is that the CPU utilization of the client has gone down tremendously, mainly because we’re using only one interface drawing library now.

Removing ANSI Color Codes With Regex

Strangely enough, I haven’t really used regular expressions until recently. They’re incredibly powerful. In fact, here’s one that replaces about 40 lines of C++ code with a single line of C#.NET code:

text = Regex.Replace(text, @”\e\[\d*;?\d+m”, “”);

It’s not absolutely perfect, but it does the trick for removing all of the ANSI color codes from a block of text.

FindMUD Becoming Somewhat Popular

I just checked Alexa stats for FindMUD.com.  Although Alexa isn’t exactly the full measure of the web since only a small percentage of people have the plugin installed, here are the MUD sites that FindMUD outranks:

mudmagic.com
mudbytes.net
mudlists.com
mudmaker.com
ftpgame.org
dikumud.com
mudlist.betterbox.net
dune.net
envy.com
silverden.com

It’s a respectable list, but we are far from surpassing the 800-pound-gorilla of MUD sites, the MUD Connector.  I don’t expect that to happen, but I do hope to get into the top three at some point (the other two being topmudsites.com and mud.de.)

Of course, FindMUD needs a lot more work that won’t happen in a single day, but I am gradually improving the site.  Just today we posted our own version of the MUD timeline.

Pex, Glorious Pex

Back when I was programming C++, I worked with a great test tool: Parasoft C++ Test.  It was great for auto-generating unit tests, which in my opinion is the best place to start.  Even if they need to be modified by a Human to get proper coverage and real-world test results, the ability to generate tests that automatically check for things like NULLs and ridiculous value ranges is a good start to build from.

Even better is the savings in time.  Manually typing out all of the tags, code, and various other “boilerplate” pieces is a pain.  With automated test generation, all you have to do is go in afterward and add rows for the tests you want to run.

This is especially helpful for larger projects (more than 100K lines of code), such as Basternae.

After creating a test project, I told Visual Studio 2008 to auto-generate tests for me.  It took about twenty minutes with the processor thinking at full speed.  I can’t imagine how long it would have taken a human, but since the Human brain functions at about 300Hz it would have taken a mighty long while.

After auto-generating 1,966 tests, I decided to run them.  It got just over a quarter of the way through with *LOTS* of failures (approximately none of this new code has ever been tested) and Visual Studio crashed.

Pex Crash Screenshot
 
One Visual Studio restart later and I was running tests again, with a massive amount of failures.

In the “CharData” class alone, 212 tests were generated and 199 of them threw exceptions on the first run.  The rest were “Inconclusive”, which is the default result for auto-generated tests.

Already, Mr. Pex has made it obvious that the application has some architectural flaws, chief among which is the random number generator.  The generator lives in an instance of the “SystemData” class when it should be in the “RandomNumber” class, which should be a singleton.  When running without the controlled startup environment of the entire codebase, things break horribly.  That’s one of the things a test framework is supposed to point out, right?

While automated test generation is not all-inclusive, Pex is extremely helpful for getting to the point where your tests are at least “Inconclusive” and ready to edit by a Human.  If you get exceptions without even getting that far, you have some work to do (as I have).

I have seen no better tool for getting a quick and easy start on unit testing.  Writing meaningful tests?  Well, that’s something you have to figure out on your own, but at least the boilerplate is done for you.

Here’s where you can get more info on Pex, including a video demonstration:

http://research.microsoft.com/en-us/projects/Pex/

It is worth noting that this Pex is extremely beta.  Every time I run it, I get the “VSTestHost.exe has stopped working” dialog box.  Even with that, all of the tests do manage to run.

Continuing Spell Migration

When we last saw our hero, he was working on migrating spells from being hard-coded in 15 different places to being individual XML data files that are loaded at boot time.

While this makes it easy to modify, enable, disable, rename, or adjust spells without a recompile, the main reason I’m doing so is because there’s just so dang much clutter in the codebase with spell info strewn about everywhere.  It’s like a pack of wizards exploded in there, I swear.

This will also make it far easier to make minor adjustments for balance.  Instead of having to track down a developer to go through many slow tweak-recompile-reboot cycles just to adjust spell damage, the “balance engineer” will be able to work independently.  In the future it may be possible to perform online editing of spell attributes without a reload.  This is obviously not something that everyone should be allowed to do.

Part of the migration will be to move most of the actual function code into the spell files.  Most spells are pretty generic in nature — add an affect (flight, strength, poison) or affect hitpoints in some way (fireball, heal).  Even so, the same ~10 lines of code are duplicated for pretty much every spell with only the name changed.

Making the spells somewhat independent of the game engine also makes the engine less “tied” to Basternae.  At some point I’d like to create a space-based MUD using the same code, and the spells would obviously be dead weight.