Tag : programming

Parsing XKB files with antlr

antlr (well, antlr3) is an amazing tool that replaces lex/flex, yacc/bison.

One would use antlr3 if they want to deal with Domain-Specific Languages (DSL), an example of which are the text configuration files.

In our case, we use antlr3 to parse some of the XKB configuration files, those found in /etc/X11/xkb/symbols/??.

Our aim is to be able to easily read and write those configuration files. Of course, once we have them read, we do all sorts of processing.

The stable version of antlr3 is 3.0.1, which happened to give lots of internal errors. It has not been very useful, so I tried a few times the latest beta version 3.1b, and eventually managed to get it to work. If I am not mistaken, 3.1 stable should be announced in a few days.

When using antlr, you have the choice of several target languages, such as Java, C, C++ and Python. I am using the Python target, and the latest version that is available from the antlr3 repository.

Here is the tree of the gb layout file,

tree = (SECTION (MAPTYPE (MAPOPTIONS partial default alphanumeric_keys xkb_symbols) (MAPNAME “basic”)) (MAPMATERIAL (TOKEN_INCLUDE “latin”) (TOKEN_NAME Group1 (VALUE “United Kingdom”)) (TOKEN_KEY (KEYCODEX AE02) (KEYSYMS 2 quotedbl twosuperior oneeighth)) (TOKEN_KEY (KEYCODEX AE03) (KEYSYMS 3 sterling threesuperior sterling)) (TOKEN_KEY (KEYCODEX AE04) (KEYSYMS 4 dollar EuroSign onequarter)) (TOKEN_KEY (KEYCODEX AC11) (KEYSYMS apostrophe at dead_circumflex dead_caron)) (TOKEN_KEY (KEYCODEX TLDE) (KEYSYMS grave notsign bar bar)) (TOKEN_KEY (KEYCODEX BKSL) (KEYSYMS numbersign asciitilde dead_grave dead_breve)) (TOKEN_KEY (KEYCODEX LSGT) (KEYSYMS backslash bar bar brokenbar)) (TOKEN_INCLUDE “level3(ralt_switch_multikey)”))) (SECTION (MAPTYPE (MAPOPTIONS partial alphanumeric_keys xkb_symbols) (MAPNAME “intl”)) (MAPMATERIAL (TOKEN_INCLUDE “latin”) (TOKEN_NAME Group1 (VALUE “United Kingdom – International (with dead keys)”)) (TOKEN_KEY (KEYCODEX AE02) (KEYSYMS 2 dead_diaeresis twosuperior onehalf)) (TOKEN_KEY (KEYCODEX AE03) (KEYSYMS 3 sterling threesuperior onethird)) (TOKEN_KEY (KEYCODEX AE04) (KEYSYMS 4 dollar EuroSign onequarter)) (TOKEN_KEY (KEYCODEX AE06) (KEYSYMS 6 dead_circumflex NoSymbol onesixth)) (TOKEN_KEY (KEYCODEX AC11) (KEYSYMS dead_acute at apostrophe bar)) (TOKEN_KEY (KEYCODEX TLDE) (KEYSYMS dead_grave notsign bar bar)) (TOKEN_KEY (KEYCODEX BKSL) (KEYSYMS numbersign dead_tilde bar bar)) (TOKEN_KEY (KEYCODEX LSGT) (KEYSYMS backslash bar bar bar)) (TOKEN_INCLUDE “level3(ralt_switch)”))) (SECTION (MAPTYPE (MAPOPTIONS partial alphanumeric_keys xkb_symbols) (MAPNAME “dvorak”)) (MAPMATERIAL (TOKEN_INCLUDE “us(dvorak)”) (TOKEN_NAME Group1 (VALUE “United Kingdom – Dvorak”)) (TOKEN_KEY (KEYCODEX BKSL) (KEYSYMS numbersign asciitilde)) (TOKEN_KEY (KEYCODEX AE02) (KEYSYMS 2 quotedbl twosuperior NoSymbol)) (TOKEN_KEY (KEYCODEX AE03) (KEYSYMS 3 sterling threesuperior NoSymbol)) (TOKEN_KEY (KEYCODEX AE04) (KEYSYMS 4 dollar EuroSign NoSymbol)) (TOKEN_KEY (KEYCODEX LSGT) (KEYSYMS backslash bar)) (TOKEN_KEY (KEYCODEX AD01) (KEYSYMS apostrophe at)))) (SECTION (MAPTYPE (MAPOPTIONS partial alphanumeric_keys xkb_symbols) (MAPNAME “mac”)) (MAPMATERIAL (TOKEN_INCLUDE “latin”) (TOKEN_NAME Group1 (VALUE “United Kingdom – Macintosh”)) (TOKEN_KEY (KEYCODEX AE02) (KEYSYMS 2 at EuroSign)) (TOKEN_KEY (KEYCODEX AE03) (KEYSYMS 3 sterling numbersign)) (TOKEN_INCLUDE “level3(ralt_switch)”)))

When traversing the tree, we can then pretty-print the layout at wish:

partial default alphanumeric_keys xkb_symbols “basic” {
name[Group1] = “United Kingdom”;
include “latin”
include “level3(ralt_switch_multikey)”
key <AE02> = { [ 2 , quotedbl , twosuperior , oneeighth ] };
key <AE03> = { [ 3 , sterling , threesuperior , sterling ] };
key <AE04> = { [ 4 , dollar , EuroSign , onequarter ] };
key <AC11> = { [ apostrophe , at , dead_circumflex , dead_caron ] };
key <TLDE> = { [ grave , notsign , bar , bar ] };
key <BKSL> = { [ numbersign , asciitilde , dead_grave , dead_breve ] };
key <LSGT> = { [ backslash , bar , bar , brokenbar ] };
};
… snip …

The code is currently hosted at code.google.com (keyboardlayouteditor) and I intend to move it shortly to FDO.

Using Anjuta in Ubuntu 8.04 to develop a GNOME C++ application (gtkmm)

You can install Anjuta 2.4.1 from the Synaptic package manager. You also need to install a few development packages. I do not know if there is a nice meta-package such as build-essential (used to install compilers et al), so I’ll just ask you to install the packages by hand. A more elegant way would be very much appreciated to see in the comments.

$ sudo apt-get install build-essential libgtkmm-2.4-dev autogen automake libtool intltool libglademm-2.4-dev

That is the order of installation when you go trial by error inside Anjuta to compile a project. Each package draws in several other packages. Also, if you have the Ubuntu 8.04 DVD in your drive, most of these packages will be installed in a jiffy. We have the Greek localisation enabled, so bear with us. Thanks to Giannis Katsampiris for completing the recent update of the Anjuta 2.4 localisation.
Screenshot of Anjuta, initial screen (Localisation: Greek)
Once Anjuta is installed, you are presented with the Anjuta main window.

We then click on File/New/Project (Αρχείο/Νέο/1. Έργο),

Project creation wizard

We click on Forward here.

Choose project type

There are many many project types. We wade through and we pick to use C++ and GTKMM (C++ bindings for GTK+). We could pick any other variation; GTKMM was a request from the Ubuntu-gr mailing list.

Fill in some contact details

We then fill in some contact details.

Sorting out the project settings

There is an option to specify at this stage external packages. We opt not to specify them now.

We are actually done!

Once you click Apply (Εφαρμογή) – the button with the green tick, Anjuta will create an initial dummy package (actually a hello world application), and will run automatically the equivalent of ./configure for you.

Read to work!

Now, this is the final screen, when you start working. Here you would click on Κατασκευή/Κατασκευή έργου (Build/Build Project), so that the project gets compiled.

Then, you would click on Κατασκευή/Εκτέλεση προγράμματος… (Build/Run program…) to run the program!

Start typing!

Here is shows that we have located the source file (main.cc), and we see main().

It takes about 3 second to compile a program with g++ (at least on my system). Therefore, the dead time between (a) Let’s compile it and (b) Oh, I am running my program!, is under 5 seconds, which is good.

FOSDEM ’08, summary and comments

I attended FOSDEM ’08 which took place on the 23rd and 24th of February in Brussels.

Compared to other events, FOSDEM is a big event with over 4000 (?) participants and over 200 lectures (from lightning talks to keynotes). It occupied three buildings at a local university. Many sessions were taking place at the same time and you had to switch from one room to another. What follows is what I remember from the talks. Remember, people recollect <8% of the material they hear in a talk.

The first keynote was by Robin Rowe and Gabrielle Pantera, on using Linux in the motion picture industry. They showed a huge list of movies that were created using Linux farms. The first big item in the list was the movie Titanic (1997). The list stopped at around 2005 and the reason was that since then any significant movie that employs digital editing or 3D animation is created on Linux systems. They showed trailers from popular movies and explained how technology advanced to create realistic scenes. Part of being realistic, a generated scene may need to be blurred so that it does not look too crisp.

Next, Robert Watson gave a keynote on FreeBSD and the development community. He explained lots of things from the community that someone who is not using the distribution does not know about. FreeBSD apparently has a close-knit community, with people having specific roles. To become a developer, you go through a structured mentoring process which is great. I did not see such structured approach described in other open-source projects.

Pieter Hintjens, the former president of the FFII, talked about software patents. Software patents are bad because they describe ideas and not some concrete invention. This has been the view so that the target of the FFII effort fits on software patents. However, Pieter thinks that patents in general are bad, and it would be good to push this idea.

CMake is a build system, similar to what one gets with automake/autoconf/makefile. I have not seen this project before, and from what I saw, they look quite ambitious. Apparently it is very easy to get your compilation results on the web when you use CMake. In order to make their project more visible, they should make effort on migration of existing projects to using CMake. I did not see yet a major open-source package being developed with CMake, apart from CMake itself.

Richard Hughes talked about PackageKit, a layer that removes the complexity of packaging systems. You have GNOME and your distribution is either Debian, Ubuntu, Fedora or something else. PackageKit allows to have a common interface, and simplifies the workflow of managing the installation of packages and the updates.

In the Virtualisation tracks, two talks were really amazing. Xen and VirtualBox. Virtualisation is hot property and both companies were bought recently by Citrix and Sun Microsystems respectively. Xen is a Type 1 (native, bare metal) hypervisor while VirtualBox is a Type 2 (hosted) hypervisor. You would typically use Xen if you want to supply different services on a fast server. VirtualBox is amazingly good when you want to have a desktop running on your computer.

Ian Pratt (Xen) explained well the advantages of using a hypervisor, going into many details. For example, if you have a service that is single-threaded, then it makes sense to use Xen and install it on a dual-core system. Then, you can install some other services on the same system, increasing the utilisation of your investment.

Achim Hasenmueller gave an amazing talk. He started with a joke; I have recently been demoted. From CEO to head of virtualisation department (name?) at Sun Microsystems. He walked through the audience on the steps of his company. The first virtualisation product of his company was sold to Connectix, which then was sold to Microsoft as VirtualPC. Around 2005, he started a new company, Innotek and the product VirtualBox. The first customers were government agencies in Germany and only recently (2007) they started selling to end-users.

Virtualisation is quite complex, and it becomes more complex if your offering is cross platform. They manage the complexity by making VirtualBox modular.

VirtualBox comes in two versions; an open-source version and a binary edition. The difference is that with the binary edition you get USB support and you can use RDP to access the host. If you installed VirtualBox from the repository of your distribution, there is no USB support. He did not commit whether the USB/RDP support would make it to the open-source version, though it might happen since Sun Microsystems bought the company. I think that if enough people request it, then it might happen.

VirtualBox uses QT 3.3 as the cross platform toolkit, and there is a plan to migrate to QT 4.0. GTK+ was considered, though it was not chosen because it does not provide yet good support in Win32 (applications do not look very native on Windows). wxWidgets were considered as well, but also rejected. Apparently, moving from QT 3.3 to QT 4.0 is a lot of effort.

Zeeshan Ali demonstrated GUPnP, a library that allows applications to use the UPnP (Universal Plug n Play) protocol. This protocol is used when your computer tells your ADSL model to open a port so that an external computer can communicate directly with you (bypassing firewall/NAT). UPnP can also be used to access the content of your media station. The gupnp library comes with two interesting tools; gupnp-universal-cp and gupnp-network-light. The first is a browser of UPnP devices; it can show you what devices are available, what functionality they export, and you can control said devices. For example, you can use GUPnP to open a port on your router; when someone connects from the Internet to port 22 on your modem, he is redirected to your server, at port 22.

You can also use the same tool to figure out what port mapping took place already on your modem.

The demo with the network light is that you run the browser on one computer and the network light on another, both on the local LAN (this thing works only on the local LAN). Then, you can use the browser to switch on/off the light using the UPnP protocol.

Dimitris Glezos gave a talk on transifex, the translation management framework that is currently used in Fedora. Translating software is a tedious task, and currently translators spent time on management tasks that have little to do with translation. We see several people dropping from translations due to this. Transifex is an evolving platform to make the work of the translator easier.

Dimitris talked about a command-line version of transifex coming out soon. Apparently, you can use this tool to grab the Greek translation of package gedit, branch HEAD. Do the translation and upload back the file.

What I would like to see here is a tool that you can instruct it to grab all PO files from a collection of projects (such as GNOME 2.22, UI Translations), and then you translate with your scripts/tools/etc. Then, you can use transifex to upload all those files using your SVN account.

The workflow would be something like

$ tfx --project=gnome-2.22 --collection=gnome-desktop --action=get
Reading from http://svn.gnome.org/svn/damned-lies/trunk/releases.xml.in... done.
Getting alacarte... done.
Getting bug-buddy... done.
...
Completed in 4:11s.
$ _

Now we translate any of the files we downloaded, and we push back upstream (of course, only those files that were changed).

$ tfx --project=gnome-2.22 --collection=gnome-desktop --user=simos --action=send
 Reading local files...
Found 6 changed files.
Uploading alacarte... done.
...
Completed uploading translation files to gnome-2.22.
$ _

Berend Cornelius talked about creating OpenOffice.org Wizards. You get such wizards when you click on File/Wizards…, and you can use them to fill in entries in a template document (such as your name, address, etc in a letter), or use to install the spellchecker files. Actually, one of the most common uses is to get those spellchecker files installed.

A wizard is actually an OpenOffice.org extension; once you write it and install it (Tools/Extensions…), you can have it appear as a button on a toolbar or a menu item among other menus.

You write wizards in C++, and one would normally work on an existing wizard as base for new ones.

When people type in a word-processor, they typically abuse it (that’s my statement, not Berend’s) by omitting the use of styles and formatting. This makes documents difficult to maintain. Having a wizard teach a new user how to write a structured document would be a good idea.

Perry Ismangil talked about pjsip, the portable open-source SIP and media stack. This means that you can have Internet telephony on different devices. Considering that Internet Telephony is a commodity, this is very cool. He demonstrated pjsip running two small devices, a Nintendo DS and an iPhone. Apparently pjsip can go on your OpenWRT router as well, giving you many more exciting opportunities.

Clutter is a library to create fast animations and other effects on the GNOME desktop. It uses hardware acceleration to make up for the speed. You don’t need to learn OpenGL stuff; Clutter is there to provide the glue.

Gutsy has Clutter 0.4.0 in the repositories and the latest version is 0.6.0. To try out, you need at least the clutter tarball from the Clutter website. To start programming for your desktop, you need to try some of the bindings packages.

I had the chance to spend time with the DejaVu guys (Hi Denis, Ben!). Also met up with Alexios, Dimitris x2, Serafeim, Markos and others from the Greek mission.

Overall, FOSDEM is a cool event. In two days there is so much material and interesting talks. It’s a recommended technical event.

OpenVistA information system for hospitals and medical care

It is quite common to expect the availability of free and open-source software for common needs, such as an operating system and an office suite. What is the situation when your needs are much more advanced? Such as, when you are looking for an information system for a hospital?
Luckily, there is such a software package for an information system for hospital needs, called OpenVistA. OpenVistA comes from VistA, a public-funded medical system for the United States Department of Veterans Affairs. Due to the source of the funding, the source code of the medical system has been available with a liberal license, and gave birth to OpenVistA.
An interesting issue with OpenVistA is that the backend is written with the MUMPS programming language. This programming language is quite old with syntax dissimilar to modern languages. However, MUMPS has become popular in medical care systems and especially VistA. There are people that criticize the programming language; it is important to understand that a big piece of software working well has much more weight over the language preferences. In addition, the front-end is what the end-user uses, and in our case it is written with modern programming languages.
Screenshot of Mono frontend of OpenVistA
Traditionally, the major front-end of OpenVistA was written in Delphi. Quite recently, a new front-end has been written, in Mono. Thanks to Mono, the front-end is cross-platform and supports i18n (the front-end can be translated in many written languages).
You can try out OpenVistA straight away by downloading the OpenVistA VMWare appliance (image file that contains an installation of an operating system, configured and ready to use). The specific VMWare appliance is based on Xubuntu.
Software for hospitals is quite expensive, and is a lucrative business for software houses. However, when one takes into account that in many countries hospitals are public-funded, it is easy to understand how important it is to use free and open-source software in this case. Sadly, in many cases, hospitals make ad-hoc agreements for such software, resulting to inefficient use of public funds.

Παρωχημένα πράγματα

παρωχημένος -η -ο [paroiménos] E3 : που ανήκει στο παρελθόν: O ιστορικός μελετά παρωχημένες εποχές. || (γραμμ.) Παρωχημένη λέξη / έκφραση. Παρωχημένη σημασία / χρήση μιας λέξης, που υπήρχε παλαιότερα. || (γραμμ.) ~ χρόνος, συντελεσμένος. [λόγ. < αρχ. παρῳχημένος (γραμμ.: ελνστ. σημ.)]

Πηγή: http://www.komvos.edu.gr/dictionaries/dictonline/DictOnLineTri.htm

Υπάρχει συζήτηση στη λίστα i18ngr για το αν είναι κατάλληλη η λέξη παρωχημένος για τη μετάφραση του όρου deprecated (π.χ. the use of the abort3() system call is deprecated).

Στην Πληροφορική, ο όρος deprecated έχει την έννοια της σταδιακής απόσυρσης ενός χαρακτηριστικού σε λογισμικό. Δηλαδή η λειτουργία είνα διαθέσιμη τώρα, ωστόσο στο μέλλον δεν θα είναι διαθέσιμη πια.

In computer software standards and documentation, deprecation is the gradual phasing-out of a software or programming language feature.

Πηγή: http://en.wikipedia.org/wiki/Deprecated

Η λέξη παρωχημένος τείνει να έχει αρνητικό connotation και σε μερικές καταστάσεις έχει χρήση ως βρισιά.

Ποιος είναι ο πιο κατάλληλος όρος για τη μετάφραση του deprecated;

Είσαι προγραμματιστής;

Το Google διοργανώνει Διαγωνισμό Πληροφορικής αυτό το μήνα, το Google Code Jam Europe. Ο διαγωνισμός διεξάγεται μέσω Διαδικτύου μέσα από μια ενδιαφέρουσα πλατφόρμα. Γραφτείτε τώρα και έχετε τη δυνατότητα να δοκιμάσετε την πλατφόρμα με προβλήματα-δείγματα.

Only four of the 48 best computer programmers in the world are Americans, at least according to a computer-programming competition run by TopCoder. Poland had 11 of the final 48, and Russia had 8. Wall Street Journal columnist Lee Gomes asks whether this is more evidence of a sad decline in American education and competitiveness: ‘Surprisingly, the Eastern Europeans don’t seem to think so. Poland’s Krzysztof Duleba, 22, explained that in countries like his own, there are so few economic opportunities for students that competitions like these are their one chance to participate in the global economy. Some of the Eastern Europeans even seemed slightly embarrassed by their over-representation, saying it isn’t evidence of any superior schooling or talent so much as an indicator of how much they have to prove.’

Πηγή: The Wall Street Journal

Υπάρχουν άραγε οικονομικές ευκαιρίες στην Ελλάδα;

Σύνδεσμοι – Τεχνολογίες Web και Wikipedia/Leonariso

Μέχρι να βγει κάποιο λειτουργικό πρόγραμμα που να διατηρεί στο διαδίκτυο πληροφορίες προφίλ, καταγράφω τα παρακάτω:

Το Experiments in Web Programming περιγράφει αναλυτικά τη δημιουργία σελίδων HTML με τεχνολογίες CSS, DOM κτλ. Όμορφα πράγματα.

Ο Leonariso γράφει στο Wikipedia. Ο πηγαίος κώδικας του Wikipedia βρίσκεται στο MediaWiki development.