I participated in GSoC for Go OpenOffice, which is a project that maintains a set of patches on top of OpenOffice. Go OpenOffice is the OpenOffice version distributed with OpenSuSE, Ubuntu and other distros, it is allegedly a lot better than the official OpenOffice release. And also available for Windows.

Hacking OpenOffice have been a very exciting experience. I haven’t worked on a project so large and complex before. It easily takes 2 hours to build OpenOffice and the sources and binaries fills about 13 GiB. Luckily I didn’t have to rebuild everytime I had to test something.

The visual formula editor, see video above, is not production ready yet. That is it needs extensive testing and a few extra features… However, I plan to keep working on it. You can read more about it’s features and current status here.

I don’t think I’ll keep updating that wiki page, but rather post some updates here once in a while. If you are eager to help test this feature when it comes that far, feel free to leave a comment with your email…

Temaet for årets børnesommerlejr var cirkus. Dette skulle selvfølgelige reflekteres i hiken, hvor vi bl.a. havde kapløb i klovne sko, flødeskums kast (på leder) og tiger tæmning som poster. Anders og jeg var posteret ved tiger tæmnings posten, her skiftedes vi til at kravle rundt, skærer tænder og skrige os hæse, mens ungerne skulle pacificeres os med pakketape. Nedenunder ses, en farlig tiger (mig), indfanget af 8 friske tiger tæmnings aspiranter .

Til trods for et par dråber regn forløb hiken helt godt… Vi overlevede alle sammen, selvom vi savnede vores har-alt-mulig-i-traileren-mand Jens Christian, det forlyder dog at han kommer igen næste år . Udover et par dråber på hiken fik vi ikke noget regn på børnesommerlejr. Men det betyder jo ikke at man kan forblive tør, når ungerne får lov at give en leder vand til lejrbål hvis de har det pæneste telt. Således gik det altså til at jeg ikke kunne komme til lejrbål uden at blive våd…

This semester my group have designed and implemented a small statically typed object oriented language slightly inspired by Python. We wrote our own lexer and parser generator in Python, and implemented the compiler in C++. And just for the record we implemented the DFA of the lexer and PDA of the parser using goto’s, inspired by re2c, this was quite fun and the result very fast.

The language is called groo (that was the best name we could come up with), it compiles into gril (groo intermediate language) which in turn run on VROOM (groo virtual machine) where memory is managed by MOM (Mark-sweep Object Manager). Whilst this isn’t the best project yet, and all the acronyms doesn’t make much sens, I really like to say that when we need to release memory we call MOM to clean up
(I appoligies for my crazy sens of humor).

I don’t think the project is of much use to anybody else… But if you want to play with simple, well documented compiler in C++, this might be it… Also the parser generator is AFAIK pretty unique, haven’t see anybody else implement a parser using goto’s… Anyway the project report and groo compiler source code is all in English and available here:

• Project report (1.5 MiB PDF)
• Compiler source code (16,5 MiB tarball)

• Project page
• Git repository

By the way did I mention, git is really nice… I just had a little fun making a bugfix branch and merging it…

I’ve found the patterns applicable many places, and recently had the privilege of using one in my C# programming exam. I previous mentioned this book when I discussed “Framework Design Guidelines“, which I wasn’t too happy about at the time… However, “Design Patterns” is definitely the book for writing reusable code, whereas “Framework Design Guidelines” is more concerned with the usability of the APIs.

Anyway, that was a word on “Design Patterns”, definitely worth a read…

The result is bindings for a subset of ZBar and a Gtk# bar scanning widget. I don’t intend to maintain the source, but if you find any bugs etc. or wish to start a project for the bindings, please leave a comment…

• zbar-sharp documentation
• Download zbar-sharp

The example application using the bar code scanning widget can be seen on to right. Note: this was a really lousy webcam . The check-mark appears when a bar code have been recognized and then fades away.

In Foodolini we used HAL to detect webcams as they were plugged, however, having heard that Ubuntu will be deprecating HAL, I didn’t care to clean up the source for this feature. If you interested it can be found in the source for Foodolini. And if anybody should happen to know how to detect webcams, distro independently, without HAL, please leave a comment…

Anyway, for this project we analyzed, designed and implemented system for managing recipes and food in a common household. The system was suppose to compute nutritional intake and manage diets and exercises as well, however, these features were never fully designed and implemented. Nevertheless, it uses the USDA National Nutrient Database for Standard Reference, to find the nutritional content of various groceries.

The system is called Foodolini and was implemented in C# on Mono using Gtk#, but also runs on .Net and Gtk# for .Net. Foodolini uses Sqlite as database, and we wrote a simple and neat ORM tool, inspired by SubSonic‘s SimpleRepository. However, the most interesting feature in my opinion is the bar code scanner used when registering groceries in the system. It’s implemented using a ZBar which captures and scans images from a webcam. I’ll be release C# bindings for ZBar and a Gtk# widget in an upcoming blog post, when I’ve cleaned it up a bit…

• Foodolini 1.0.0 (sources, binaries and documentation)
• Report (documenting the analysis, design and implementation of Foodolini)

Anyway, I needed a MusicPlayer module that would make it easy to publish music in Flash based music player, so I wrote one. The documentation for pluck is fairly good, php on the other hand is horrible (it took me a while to figure out I had to enable error reporting). Nevertheless, the result allows the user to upload mp3s, choose player skin and settings. For playback I used Xspf Jukebox which has 20 skins included some of which are fairly good looking…

You can download the module here… It’s for pluck 4.6, tested with 4.6.3.

Update: This plugin is now hosted at github: github.com/jopsen/pluckplayer.

While writing a backend for Pwytter I also created some abstractions for micro-blogging services, so that Pwytter supports multiple accounts and multiple services (currently Twitter and Identi.ca). With this new backend all the messages are also cached in an sqlite database, enabling Pwytter for work while offline.

I also added theming support to the Qt frontend I wrote for Pwytter, above is a screenshot of Pwytter running the “Twitter-like” theme (as you can see have also be translated, so far only to Danish). Pwytter uses WebKit to display tweets, users and other types of content, thus themes can customize the GUI using HTML templates and Qt stylesheets. Documentation for writing such themes can be found in the project wiki, I plan to write an article on subject when this Pwytter branch is released. So far this Pwytter branch is still under development, and interested developers can find install instructions in the project wiki.

A few months ago I felt like I needed to get better at writing clean reusable code, so I impulsively bought a book called Framework Design Guidelines, Conventions, Idioms, and Patterns for Reuable .NET Libraries. Now having read the thing I must admit that I found large parts of it rather boring. The book is mainly presented in “Do”/”Do not” form, however, interrupted by annotations that discusses these guidelines, and gives examples to where these are followed or forgotten in the .Net Framework.

Apart from the annotation this book is mainly about usability of .Net libraries, conventions and guidelines for the public interface of a .Net library. This book only briefly touches a few design patterns, but apart from these it’s all about the public interface and how to design this in order to facilitate extensibility. So if you’re look for coding guidelines on how to design the public interface for a .Net library this is the book. However, I was probably a bit to impulsive, so I’ll be reading Design Patterns next…