Stefan-Marr.de

Finally, I managed to complete the changes for the traits patch. Since, PHP 5.3 already entered the release cycle and it is not sure whether there will be a PHP 5.4 with new language features, the new patch is written for the PHP6 codebase.

In its current version, it implements the RFC with the proposed syntax and functionality. There are still some parts missing for a complete integration into the PHP landscape. Most noticeable is the lack of reflection support at the moment. I will add it, when the patch has reached a level of stability to be included in the official language.

For testing purpose, you can use the following patch, archive with test cases.

The patch is build for cvs -d :pserver:cvsread@cvs.php.net:/repository checkout php6. More information on how to build the PHP source from CVS is available at php.net.

Patch:

• traits.patch
• Test Cases

In case of any problems applying the patch on the CVS checkout, you can use this code snapshot with traits: php6-traits.tar.bz2

Since I started my PhD studies at the Programming Technology Lab (PROG) at the VUB in Brussels a while ago, I had to update my pages a bit to reflect my new live as a scientist. You might have noticed, now this blog contains also some details about myself. You will find also some thoughts about my research and maybe at some point in time a real publication My office is located here, if you like to give me a visit:
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Yes! Finally! I am done with my Master’s Thesis.

It was a lot of work, but it was worth it. The results are quite interesting. Especially, if you’re interested in modularization, architecture, separation of concerns and may be even high-level language virtual machines. Unfortunately, I had not the muse and time to write the whole thesis in English, but the abstract will give you some hints what it is about. In addition, hopefully, there will be a publication derived from my work which summarizes the results early next year. Until then, you have to know German to read the whole thesis

Modularization of Virtual Machines: Implementation and Evaluation of an Architecture Description Language

Abstract

Today, high-level language virtual machines are custom-made special purpose systems optimized for specific domains like embedded devices. Their implementation suffers from high complexity, strongly intertwined subsystems and little maintainability. This is caused by insufficient modularization techniques failing to represent the system architecture in the code. To overcome this situation, the Virtual Machine Architecture Definition Language (VMADL) has been proposed. In this work, the language features of VMADL are investigated and a VMADL compiler is implemented to conduct a case study on an existing Smalltalk VM written in C named CSOM.

The aim of this case study is to test the language on CSOM and to modularize it in a way that it is possible to build a product family of VMs out of it, to be able to benefit from a product-line approach for customizing VMs. In a first step, CSOM is reverse engineered and several feature implementations are analyzed for their specific requirements on modularization. Based on this examination, a CSOM specific feature-oriented class definition language is added to VMADL to allow a completely modularized implementation of all analyzed features.

Afterwards, the case study is evaluated using several metrics to prove that the code overhead caused by VMADL is minimal and necessary for the architecture and modularization. Furthermore, it is shown that there is no negative impact on the runtime performance of the system. To prove the positive influence of VMADL on architectural comprehension and maintainability, an experiment with students is designed and conducted. Eventually, this work demonstrates how VMADL can be used to explicitly express the architecture of a VM in the code, improve modularization, and add the necessary variability to build a VM product family.

• PDF: Masterarbeit - Modularisierung virtueller Maschinen

One important part in research is the discussion with other people about your research topic, and well, the SVPP’08 was my first real research event and I really enjoyed it

I meet some very interesting people discussing things, which are somehow related to what I am actually doing in my Master’s Thesis. So, I not only got some more insight what there is going on in the community, but also suggestions according to my topic and a starting-point to get a scholarship for my PhD.

Ok, in the end of this two-day event, the "old guys" got lost in some esoteric discussions, but this seams to be the way how it goes.

For my first real research event, where I have actively participated, it was worthwhile.

My talk was about the architecture definition language, which I have analyzed and enhanced in my Master’s Thesis. What it is all about is discussed very briefly in this extended abstract. In the next weeks, there should be also videos for all talks on the official symposia website.

Heute, am zweiten Tag der Unconference hier in Hamburg, hab ich endlich ein wenig Zeit mir auch ein paar Vorträge an zu hören. Gestern musste ich unerwarteter Weise gleich zwei mal ran.

Meine Sessionvorschläge zu den Themen Metaprogrammierung und Traits wurden beide gewählt und ich durfte dementsprechend zwei mal 45min vortragen.

Die Folien zu den beiden sind einmal als PDF verfügbar und außerdem hab ich sie bei Slideshare eingestellt, mal sehen wie gut das funktioniert.

Metaprogrammierung und Reflection: Tool-Entwicklung für und mit PHP
Slides als PDF

Traits: A Language Feature for PHP?
Slides als PDF