Loki's blog

"Community commands (those hosted on individual servers, locally, or on the herd), however, cannot be localized at this time." (via: Labs/Ubiquity/Ubiquity 0.5 Making Commands Localizable - 09.07.10)

In one of my projects, I had to look for certain objects using certain qualifiers: ID, Name, ID & Name, etc… Without optional parameters (Hello C# 4.0!), I ended up with copying & pasting whole blocks of code: initializing, filtering, returning the result, error handling, etc. I wondered if there was an easier solution to that and then it hit me! LINQ & delegates!

Let’s start with a simple class:

public class Employee
{
    public string FirstName { get; protected set; }
    public string LastName { get; protected set; }
    public int Id { get; protected set; }
    //...and other methods...
}

Then, we have a List of Employees:

List<Employee> Employees = new List<Employee>()
    {
        new Employee("Juan", "dela Cruz", 1),
        new Employee("John", "Doe", 2),
        //and so on...
    };

Now let’s try making some convenience methods for retrieving a collection of filtered Employees.

public IEnumerable<Employee> GetByLastName(string last)
{
    IEnumerable<Employee> result = 
        Employees.Where(emp => emp.LastName == last);
    return result;
}

public IEnumerable<Employee> GetById(int id)
{
    IEnumerable<Employee> result =
        Employees.Where(emp => emp.Id == id);
    return result;
}

Quick & easy, yes? Now what if instead of a List, our collection of Employees isn’t that stable. We’d need to put each of them in try-catch blocks and add error handling. This can quickly become high-maintenance code.

Enter LINQ and delegates!

We then basically need one method that will contain all the error handling, initialization and whatnot. We just pass a delegate will filter the collection:

public IEnumerable<Employee> GetEmployee(Func<Employee, bool> query)
{
    try
    {
        //initialization
        IEnumerable<Employee> result = Employees.Where(query);
        return result;
    }
        //handling other exceptions...
    catch (Exception ex)
    {
        //Error handling
        return null;
    }
}

Did you notice: Func<Employee, bool>? All we need is to pass an expression that uses the Employee as input and returns a boolean (true if it passes the condition or false if not).

What does this mean? Well, we can now replace the convenience methods we wrote earlier with this:

public IEnumerable<Employee> GetByFirstName(string first)
{
    Func<Employee, bool> query = emp => emp.FirstName == first;
    return GetEmployee(query);
}

public IEnumerable<Employee> GetById(int id)
{
    Func<Employee, bool> query = emp => emp.Id == id;
    return GetEmployee(query);
}

We’re back to code that’s easy to maintain with all the initializations, error handling and other code blocks that you need.

You could even do away with the convenience methods and use lambda expressions all the way!

GetEmployee(emp => true); //get everything
GetEmployee(emp => emp.LastName.Contains("Locs"));
GetEmployee(emp => emp.FirstName == "Richard"
    && emp.LastName == "Locsin");

Have fun!

Related resources:

• LINQ
• Lambda Expressions

• Right-click the taskbar, choose Toolbars / New Toolbar
• In the folder selection dialog, enter the following string and hit OK: %userprofile%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch
• Turn off the “lock the taskbar” setting, and right-click on the divider. Make sure that “Show text” and “Show title” are disabled and the view is set to “small icons”.
• Use the dividers to rearrange the toolbar ordering to choice, and then lock the taskbar again.

The beta is feature complete; although there are "a couple of things that we're holding back", according to general manager Mike Ybarra. ... "all of the code is in the build, just the discoverability is not." ...

Read the rest of this post »

I just bumped into a clever little code snippet used to find the inverse square root:

float InvSqrt(float x) {
    float xhalf = 0.5f * x;
    int i = *(int*)&x;   // store floating-point bits in integer
    i = 0x5f3759d5 - (i >> 1);  // initial guess for Newton's method
    x = *(float*)&i;  // convert new bits into float
    x = x*(1.5f - xhalf*x*x);  // One round of Newton's method
    return x;
}

[ taken with comments from Kalid Azad @ BetterExpalined.com: Understanding Quake’s Fast Inverse Square Root. ]

Ok, it does not get the exact value but you get a good enough estimate, FAST!

There are two important things to note here:

• Newton’s method (also known as the Newton-Raphson method)
• The ‘magic number’: 0x5f3759d5, an optimized first guess

For a better explanation, I suggest reading Kalid Azad’s article and the paper by Charles McEniry.

Wait a minute, so why is this useful?

In graphics programming, this can be used to normalize vectors quickly. If you noticed the title on the first link, it’s used in the Quake 3 engine. So does that mean the legendary John Carmack wrote this code? If you’re interested, you can read the Origin of Quake3’s Fast InvSqrt() at Beyond3D.

What did I learn?

I usually forget one thing: there are times when speed trumps accuracy. A close quick estimate would be better and there are a number of optimations that can be made. Much thanks goes to Doc Mana who first introduced me to the Newton-Raphson method & how to apply it on code. 

• You can import bookmarks, passwords, etc. from your current browser
• It's noticably faster
• Cleaner = More page real estate! (It may take some time for me to get used to this...)
• Text in the address bar is more readable (it's bigger!)
• Firefox shortcuts work! (Alt+D/Ctrl+L, Ctrl+J, Ctrl+H, etc..)
• Autocomplete isn't intrusive and it really works
• Draggable tabs (moving them like FF...and OUTSIDE to put them in their own window!)
• Speaking of tabs, you can also drag your Firefox tab to Google Chrome! 
• There's Incognito mode (or "porn mode" if you're the type)
• The new tab page is unexpectedly useful
• Did I mention it's really fast? Wooo~! JavaScript!
• When right-clicking on a link, "Open link in new tab" is the first option instead of "new window." It also loads NEXT to your current tab, not at the end like in Firefox
• If one page causes a crash, the other tabs are unaffected. Finally!
• Downloads window is now a Downloads tab. Less intrusive = better
• When searching for terms, results outside the visible area is shown in the scroll bar! Neato!

• No spell check Whoops! I think it's just wordpress...Or maybe it's new? Ooh! they updated it!
• No real-time search in the History tab
• No user profiles
• No "master password" to protect all your saved passwords
• Plugins/Extensions are (currently) missing. (If you're extension-depended, stick to your current browser...for now at least)
• The feed button is nowhere to be seen (tell me if you find it)

12. Software updates 12.1 The Software which you use may automatically download and install updates from time to time from Google. These updates are designed to improve, enhance and further develop the Services and may take the form of bug fixes, enhanced functions, new software modules and completely new versions. You agree to receive such updates (and permit Google to deliver these to you) as part of your use of the Services.

17. Advertisements 17.1 Some of the Services are supported by advertising revenue and may display advertisements and promotions. These advertisements may be targeted to the content of information stored on the Services, queries made through the Services or other information. 17.2 The manner, mode and extent of advertising by Google on the Services are subject to change without specific notice to you. 17.3 In consideration for Google granting you access to and use of the Services, you agree that Google may place such advertising on the Services.

info["Errors"] = context.AllErrors == null ?
    "" :    string.Join( "<br/><br/>",
        (from error in context.AllErrors
        select String.Format( "{0}<br/>{1}",
            error.Source, error.Message))
       .ToArray<string>());

Posted by email from goofydelinquent's posterous

Ubiquity is an experimental Firefox extension that gives you a powerful new way to interact with the Web. You're used to telling Firefox where you want to go by typing Web addresses into the URL bar. With Ubiquity installed, you'll be able to tell Firefox what you want it to do by typing commands into a new Ubiquity input box.

(Source: Ubiquity 0.1 User Tutorial)

(Source:Ubiquity for Firefox from Aza Raskin on Vimeo.) Neat stuff. I, myself, am so excited that I can't help but try messing with Ubiquity. The result: A Ubiquity command for Ping.fm. Ping.fm: Updating social networks in a snap With a lot of social sites around (like Facebook, Twitter, Tumblr, Plurk, Livejournal, Yahoo! 360, Delicious, etc.), I can't help but be a member of a number of them. What usually happens is that some of my friends on one network is not a member of another. To update everything would be a pain and so there's Ping.fm!

Ping.fm was created for the sole purpose of making it as easy as possible to share your posts with the world. Now you don't have to fumble around the web in order to post anymore, you can just post once, and be done with it.

(Source: Ping.fm/About)

• Ubiquity in Depth by Aza Raskin
• Ubiquity User Tutorial
• Ubiquity Author Tutorial

• iPhone completely blocks free software. Developers must pay a tax to Apple, who becomes the sole authority over what can and can't be on everyone's phones.
• iPhone endorses and supports Digital Restrictions Management (DRM) technology.
• iPhone exposes your whereabouts and provides ways for others to track you without your knowledge.
• iPhone won't play patent- and DRM-free formats like Ogg Vorbis and Theora.
• iPhone is not the only option. There are better alternatives on the horizon that respect your freedom, don't spy on you, play free media formats, and let you use free software -- like the FreeRunner.

1. After using the Microsoft's OS's for over 10 years, I don't find Mac's OS user-friendly. It looks cool but function should take priority over form.
2. It's overpriced. Want proof? Here's a comparison of the Dell Inspiron 1720 and a MacBook Pro 17-inch:

While it's true that there are advantages to an apple computer in software and hardware and tech support and whatnot, it's insufficient to justify a nearly $2k price difference. What it comes down to is paying for style over substance, and anyone who says differently is lying or stupid.

Ok, what I do own is an 4th generation 20 GB iPod. I'm quite satisfied with it, despite the fact that I had to get it fixed last year when I got this error (cute icon though), and a year before that. But that's just it! I've become used to it and had been drowned by the hype that I didn't bother with complications Apple didn't mention.

• I have to use iTunes to import songs into my iPod and to listen to them while it's connected to my computer. Thankfully, there are quite a number of hacks out there so that I don't have to use this memory hog. Aside from that, there are Linux apps (with much resistance from Apple) that can read the iPod's weird file storage system that brings me to point #2.
• I cannot export the songs I have on my iPod, even if I got the files from that computer in the first place. Let's say I have my music library in my iPod & hard drive. For some reason, my hard drive got corrupted so my whole music library is lost. I cannot intuitively transfer the songs in my iPod back to my computer. I need to download more hacks to be able to that. I try copy the contents of my iPod as is, but it's not human readable.

If we give more "value" to such terms, we might end up in a grim world for consumers. Finally, just to end on a lighter side:

(images from: reddit: The problem with Apple, Apple iMac vs Dell XPS 410)

The registry cannot load the (hive) file: SystemRoot/System32/config/SOFTWARE or its log or alternate. It is corrupt, absent, or not writeable. Beginning dump of physical memory. Physical memory dump complete. Contact your system administrator or technical support group for further assistance.

Stop: c0000218 {Registry File Failure} The registry cannot load the hive (file): \SystemRoot\System32\Config\SOFTWARE or its log or alternate

1. Boot the Windows Vista CD
2. Selected the option to Repair an existing installation (it's found in the second window when it finally loads)
3. Wait for it....and then done!
4. Restart and Vista should load!

1. Go to Computer > Properties > Advanced System Settings
2. Click the Computer Name tab
3. Then somewhere near the bottom, click the Change button
4. In the "Member of" portion at the bottom, select the Workgroup radio button and type in a Workgroup name ("WORKGROUP" by default)
5. You'll be asked to restart so just do that
6. Repeat the same steps 1-3
7. Instead of selecting the Workgroup radio button, select Domain and type in the network domain.
8. Restart the computer.