ThisIsNotATest

This is a tutorial about writing Ruby applications that use the Qt framework on Windows XP. For doing so, the Qt-Ruby bindings named QtRuby are used.

——RANT MODE: ON—–

Ruby programs that have a nice GUI? Is that possible? With all that Ruby On Rails stuff going on, good old desktop applications have been left behind. And so has the topic of creating a desktop application that is pleasant to use and to code.

When combining Ruby and Qt, developers finally have a chance to create Ruby GUI applications that are neither pain in the ass for developers nor pain in the eye for the user.

——RANT MODE: OFF—–

Disclaimer
At the time of writing this I have very little experience with QtRuby. However I just wanted to get started with it and did not find a decent guide for doing so on windows, so I just put together what I learned in the first few days.
For the sake of simplicity and brevity, this guide does not use the latest versions of Ruby, Qt and QtRuby. Instead, it is using prebuilt binaries and installers, that have been created by some nice guys (for getting the latest version running, see comments).
You have been warned. Comments are welcome.

Setting everything up

Getting your first QtRuby program to run under windows is surprisingly simple. You don’t even need to install Qt.

Installing Ruby

1. Download the Ruby 1.8.6 One-Click Installer from the official Ruby site: www.ruby-lang.org/de/downloads/
2. During installation, check the SciTE and Enable RubyGems options. SciTE is an editor and Gems is the Ruby package manager (we won’t need those here, but they are both very handy tools).
3. Install to c:\ruby. You may of course choose a different path, but for the rest of this guide I will assume this location.
4. When installation is finished, open a shell and type ruby --version. It should say ruby 1.8.6.

Installing QtRuby

1. Get the installer from vision.eng.shu.ac.uk/mmvlwiki/index.php/Qt4-QtRuby_installer_for_Microsoft_Windows and install it.
2. Open irb (that’s a Ruby shell) by typing irb at your Windows shell.
3. Type require 'Qt4' and execute it by pressing Enter.
4. It will complain, that it does not find mingwm10.dll, so let’s get that thingie.

Installing mingw Runtime

1. Download the mingwm10.dll from sourceforge.net/forum/forum.php?forum_id=873679.
2. Copy it to c:\ruby\bin
3. Go to the irb again and type require 'Qt4'. This time it should yield true.

That’s it! Now you are ready to begin development of QtRuby programs.
You may leave now if you want and hack away on your own. However, if you want some advice on how to start and where to get information, I kindly invite you to stay a bit longer.

Hello Qt, Hello Ruby!

Let’s see if we can greet our new friends. Type the following program into the irb. Alternatively you may copy-paste the code into a fresh file. Name it main.rb and run it with ruby main.rb.

require 'Qt'
app = Qt::Application.new(ARGV)
button=Qt::PushButton.new("Hello Ruby, hello Qt!")
button.resize(100,30)
button.show
app.exec

You should see something that looks strikingly similar to the screenshot.

Getting Help on Qt
Qt is the best-documented library I have ever seen. You can find everything at
doc.trolltech.com/4.3
(The QtRuby version you downloaded has been built against Qt 4.3.1)

The docs are available as an offline version: If you install and compile an open source version of Qt (see this post ), you will get a program called Qt Assistant (assisstant.exe) that offers the full documentation and some neat searching features.
When installing Qt, you will also get a nice program called qtdemo.exe. It contains lots of example programs (in fact the Regular Expressions ‘example’ is one of my favorite tools at work).

However, there is one drawback on both, the documentation and the example programs. It is all written for C++ coders. Damn!
Fortunately the difference between C++-Qt and Ruby-Qt is not that big. But it gets even better…

Tons of Examples (in Ruby!)
…because a very kind guy named Richard Dale converted the Qt examples from C++ to Ruby. They come with the QtRuby source package, that can be found on the Rubyforge homepage of Korundum/QtRuby (rubyforge.org/frs/?group_id=181). Let me show you how to get them running (and introduce you to the resource compiler on the way).

1. Download e.g. qt4-qtruby-1.4.9.tgz and unpack it
2. Browse to the directory qt4-qtruby-1.4.9\ruby\qtruby\examples\graphicsview\collidingmice and open a shell
3. Type ruby main.rb
4. And tadaah - you will get an error message saying no such file to load -- qrc_mice.rb (LoadError)

The reason for this error is that the resources (images in this case) have to be available for the program to work. To create the required resource file, we have to execute the Ruby-pendant of the Qt resource compiler (rbrcc, probably located in c:\ruby\bin)
Type
rbrcc mice.qrc -o qrc_mice.rb
Try ruby main.rb again. This time you should see a window with some mice running around in it.

More, More, More
When finished with this short introduction, I strongly recommend to check out
techbase.kde.org/Development/Languages/Ruby
immediately. It explains how the concepts of Qt/C++ translate to QtRuby, gives a few nice tricks, that are not possible in C++ and demonstrates some convenient features of QtRuby. There’s also a bunch of links at the bottom of that page, that points out more resources to learn about QtRuby.
Great stuff, one small warning: It appears that the example code is written for Qt 3.x. So keep that in mind when copy-pasting it.

Well, that’s it for now. Happy coding!

One problem when developing VBA applications is that bringing bugfixes and improvements to your users can be difficult since an Excel Workbook contains both, code and data. Certainly you cannot expect the typical MS Excel user to import .bas files or things like that.

To solve this problem, I wrote a small Excel tool called ‘VBA Updater’. It updates the VBA code of an Excel Workbook from another Workbook without touching the data in the Worksheets.

You can find a description and the tool at: VBA Updater

The commercial version of Qt has a very nice feature. Given a qmake project file, it is able to create a .vcproj file that can be opened with Visual Studio. If everything is setup correctly you can instantly compile your project using the Visual Studio C++ compiler. This way it is not much of a problem to develop a C++ project where some developers are linux geeks and some are lazy windows users who do not like mingw or make (for good reasons, of course) and who absolutely hate gdb (for even better reasons).

Most unfortunately, this feature was not available in the Open Source version of Qt. You either had to create their project files manually, which is a very painful task for several reasons - one of them being that the MOC and the UIC have to be integrated into the build process. Or you had to set up a Makefile project using Visual Studio. That’s what I was about to do this morning, when I stumbled across the following article:

Qt/Windows Open Source Edition to support VS Express

The most important statement in above article is the following:

“We have decided to support Visual Studio Express with Qt/Windows Open Source - we are dual licensing the MSVC Makefile and project generator (Sorry, no VS Integration for Open Source users)”

——RANT MODE: ON—–

Obviously, second-most important statement is this one:

“The Visual Studio Express environment is just so much superior and easier to use for existing Windows developers compared to what MinGW provides.” - I could not agree more.

——RANT MODE: OFF—–

So since 4.3.2 even the Open Source version of Qt is able to create vcproj files. However, since the Open Source version is configured for mingw when installed, just throwing qmake at your project file will only create a usual Makefile.

Creating a Visual Studio Project File from a qmake Project File

1. To create a vcproj file, you will have to use the correct mkspec and change the template from “app” to “vcapp”. The following command does the job for Visual Studio 2005:
   qmake -tp vc -spec win32-msvc2005
   If you are using a different version of Visual Studio, have a loot at QTDIR/mkspecs to find the correct mkspec for you. QTDIR is the directory where you installed Qt.
   If your project file was named “myproject.pro” you will now find a file named “myproject.vcproj” in the same directory.
2. Try to build the application. You will be greeted by the following error message:
   fatal error LNK1181: cannot open input file 'c:\<QTDIR>\lib\qtmain.lib', where QTDIR corresponds to the directory of your Qt installation.

Building Qt with the Visual Studio Compiler

The problem is, that the prebuilt binaries that come with the Open Source Qt distribution for Windows cannot be used by the Visual Studio compiler. Heck, they do not even have the right name.

How to fix this? Well, you have to build those files from the Qt sourcecode using the Visual Studio compiler. Do the following:

1. (Skip this step, if you are using the commercial version of Visual Studio)
   The Express Version of Visual Studio does not include the Platform SDK. Unfortunately this SDK contains some headers and libs that are required to compile Qt. Go to Windows Server 2003 R2 Platform SDK Web Install to install it. Make sure to include the Core SDK AND the Web Workshop SDK during installation.
   Have a look in the directory of the SDK and locate the file SetEnv.Cmd. Add the directory to your path (Should be something like C:\Program Files\Microsoft Platform SDK for Windows Server 2003 R2. Do not forget to surround it with double quotes (”) if it contains blanks.)
2. Add <VisualStudioDirectory> \VC\bin to your path.
3. Then open a command line and go to the Qt installation directory. Type vcvars32.bat.
   This will create the environment variables required for the next step. The batch file resides in the VC\bin directory of your Visual Studio installation.
4. (Skip this step, if you are using the commercial version of Visual Studio)
   Type SetEnv.cmd to create the environment variables necessary for including the files of the Platform SDK
5. Type configure -platform win32-msvc2005.
   This will tell Qt to prepare itself for being compiled by the Visual Studio compiler. Again, if you use another version of VS than 2005, replace win32-msvc-2005 with the makespec appropriate for you.
6. Type nmake. Then go and have a break. Compiling Qt will take a while.
   Actually, I was surprised that this last step works. Up to this day I thought that the OS version of Qt could not be built with Visual Studio. You had to apply a batch distributed by some helpful people under the name qtwin (Here is a german tutorial on that stuff). It appears that those dark days are over now.
7. Now try building your application again. Everything should work fine now.

I hope this guide helps you to get going with Visual Studio and Qt Open Source. If you have any trouble or suggestions, feel free to drop me a mail or post a comment.

As I am working on some small Excel Project, I have stuffed some new things in the VBA Library. There are new functions for talking to MS Word and MS Outlook and one function to compare arrays. Not very fancy, but I post it here anyway to make sure I don’t forget that they are there and ready to be used.

The library can be found here.

Question: How can a classic for loop

for (int i=0;i<10;++i) {
// do stuff
}

be realized in a windows batch file?

Answer:

echo off
SET /a i=0

:loop
IF %i%==10 GOTO END
echo This is iteration %i%.
SET /a i=%i%+1
GOTO LOOP

:end
echo That’s it!

The answer uses goto and the /A option of the set command. Without that option, SET interprets the right side of the equals sign as a string and i would contain ‘i+1′, then ‘i+1+1′ and so on. To make SET interpret the right side as an arithmetic operation, the option /A is required. Enter SET /? to get a detailed explanation of the SET command’s capabilities.

I just put up a first little version of a VBA library, which is a collection of function for doing stuff in Excel VBA. There are a few functions for ranges, strings and VBA modules. Currently (2007-12) I am not doing any larger VBA project. Once I work on something that has more than a few lines of code however, this library will certainly grow.

You can find the whole thing here.

The problem:
You want to have a User Form (a VBA-Dialog) which

For a solution of these problems check the following file and/or read on.
Example Code for Dynamic Dialogs in Excel VBA

Consider the following example: There is a table which contains products of some type. Each product has some properties like description, prize etc. This table is created by some database queries. Hence, you do not know how much entries the table will have.
You want to provide the user of your Excel application with an easy way to select those products and insert them in another table (e.g. an invoice). If a user wants to insert a product into the invoice, he clicks a button and you would like to present him a User Form that has one button for each product. If he clicks on one button, the concerning product is inserted into the invoice table with its description, price etc.

Read the rest of this entry »

Here’s just something I wrote some time ago and rotted on my harddisk. It might be helpful for people new to C++.

———————-
In all but the smallest projects, code is much more often read than (re)written. This means, that a large amount of the development time goes into reading code, which therefore should be made as easy as possible. It also means, that almost everything you can do, to make your code easier to be read should be done because the additional time you spent in writing the code will more than pay off in the future. We all know (and perhaps hate) some ways, to make code easier to read: use comments, use long variable names, give functions a clear name that corresponds to their purpose etc.

These rules can be applied in almost every programming language. But if you and your fellow developers really know the programming language, you can do more. You can express certain expectations and warranties by using features of the language and by this, express yourself more clearly (special bonus: you may even omit a few comments, because your code speaks for itself). Additionally, sometimes the compiler and the runtime environment help you to enforce certain requirements on how your code is to be used (see Design by Contract).

Read the rest of this entry »

When you use batch files in windows xp, you may want to call a set of batch files from another batch file. Let’s say your file is named foo.bat and looks like this:

echo off
echo "Starting foo.bat"
subFoo1.bat
subFoo2.bat
echo "Finished foo.bat"

You will never see Finished foo.bat, since the batch processing will stop after the execution foo1.bat.

To fix this, you need to call the command line processor for each batch file:

echo off
echo "Starting foo.bat"
cmd /C subFoo1.bat
cmd /C subFoo2.bat
echo "Finished foo.bat"


Or you can use the call-command:

echo off
echo "Starting foo.bat"
call subFoo1.bat
call subFoo2.bat
echo "Finished foo.bat"