I have always thought about domain specific languages as a way to not only boost productivity but also free our thoughts from these small menial and mundane tasks. I am so excited about domain specific languages that I have thought numerous times to continue some research studies in this area. Sadly I havent been able to find any good place yet in Helsinki.

QML or QtQuick is an excellent DSL for creating nicely animated user interfaces, not just for desktop computers but also for mobile devices. The productivity boost is immense, I wrote complete applications in Qt Quick in weeks which even iPhone developers took months to write. Still more wild that the Qt Quick app ran fine on N900, N8 and other Nokia Qt devices. Since that time I have been hooked on Qt Quick. I havent found a better DSL for UI’s than Qt Quick. It is so simple, no crazy xml syntax like in XAML. XAML might be more powerful but the power is lost in its complexity and IMO bad idea of using XML.

The second experience of DSL came with LINQ when I wrote my first app for Windows Phone. I had previously done similar app on Android, iPhone and Qt/Symbian where I needed to parse huge XML documents, so I had to spend weeks just to write the code to handle the SAX events and create a state machine. This code was fragile and just too much work. Thank god for json.

Coming back to the point, the experience of parsing XML with LINQ was quite the opposite, it was … pleasant and enjoyable. I was amused by the speed at which I wrote the code and how simple it was. It all made sense.

I think Microsoft is on the right path. They already have two DSL’s incorporated in Windows Phone development, writing apps therefore for WP is quite easy and fun experience.

I hope in the future DSL’s will become even more common and we will have write apps in DSLs which are then glued together by a general purpose language.

While Qt offers many many nice features which make Objective-C look like from stone age. Objective-C has some nice features as well, one I mentioned in my previous post, which Qt already solves rather nicely and in a better way as one of the commenter pointed out. Objective-C and Qt are quite similar in a sense that they provide improvements on top of an already existing language. Qt with meta object compiler and Obj-C with something similar.

So back to the point, I now use Q_PROPERTY macro in my QObjects based classes a lot:

class Person : public QObject
{
Q_OBJECT
Q_PROPERTY(QString name READ name WRITE setName)

public:
void setName(const QString& aName) { iName = aName; }
QString name() const { return iName; }

private:
QString iName;
};

Now consider this Objective-C code:

// person.h
@interface Person : NSObject
{
NSString* name;
}
@property (nonatomic, retain) NSString* name; // same as Q_OBJECT 

// person.m:
@implementation Person
@synthesize name; // this generates getter/setter in the .m file

// rest of the code ...

So do you see what I see ? In the Objective-C version of the code I don't have to write the getter and setter methods, whereas in Qt i have to. I think all the information to automatically implement the getter and setter functions is already in the Q_PROPERTY macro, may be the moc compiler can go ahead and also generate the getter and setter methods for us ?

But perhaps the best thing about N900 is that my Qt apps that I write for  Symbian  also work with little modifications on my N900! you dont even need to install some crazy toolchains or use the linux os to do any of this; with the Nokia Qt SDK you can do all of this from your windows computer. Even though its in beta right now; but every thing works; i am using it for a meego/maemo app i am doing and no issues yet

First you need to install it in your iphone/ipod.  Search for ‘Touch Mouse’  in the app store, install it. Then go to Logitech Touch Mouse Server Web site, and get the server software for what ever your OS is. It seems only Linux is not supported. Sad! . Install the server, then run the app on your iphone/ipod, it will detect your computer and hit connect.

So while this is very neat, not every one has a iphone/ipod ( I have a first generation ipod touch ). It would be really great if there was a similar app for the Symbian phones, Android, WebOS or Maemo phones.

To do that we need to understand the protocol used by the touch mouse server and the client. My investigation just came to the conclusion that its a UDP based protocol, the app also uses bonjour for service discovery. The UDP protocol is very cryptic and it seems this is not a easy task, it would be just great if Logitech can release some documents on this.

in the command prompt:
SET LIB=c:\openssl\lib\mingw;%LIB%
SET INCLUDE=c:\openssl\include;%INCLUDE%
SET PATH=c:\openssl;%PATH%

now go to the Qt source folder and execute the configure.exe like so:

configure.exe -openssl

and finally
mingw32-make

and here a nice demo of qt4.6 while it compiles for you.

the repository is hosted at http://gitorious.org/qfacebookconnect

Currently the project is in copy / paste / compile mode. But once I have all the files compiling I will optimize it for Qt. Please have a look and join if you are interested !