I stumbled over this funny site called CodeGolf.com and tried my luck on the first problem (actually it’s the sixth, but it was the last and therefore appeared first on their page – confused?) Writing a Brainfuck Interpreter:

The brainfuck language uses a simple model of a computer consisting of an array of memory cells, a movable pointer into the array, an output stream, an input stream and the program itself. The program is formed from a sequence of the below commands :

• > – Increment the pointer to point to the next cell to the right.
• < – Decrement the pointer to point to the next cell to the left.
• + – Increment the byte pointed to by the pointer.
• - – Decrement the byte pointed to by the pointer.
• [ - Jump forward to the command after the corresponding ] if the byte at the pointer is zero.
• ] – Jump back to the command after the corresponding [ if the byte at the pointer is non-zero.
• . – Output the value of the byte at the pointer.
• , – Accept one byte of input, storing its value in the byte at the pointer.

It didn’t take me very long to write a running interpreter. My first version was more than a thousand characters. Even after renaming the variables and stripping all the whitespaces I still needed around 700 characters, which is huge compared to the best Ruby solution with only 142 characters. Read the rest of this entry »

This is a great thread on Lamba the Ultimate. The quality of posts at LtU is usually pretty good, but this one is even better. What really suprised me is the lack of flaming. Probably because of the “that you can’t prove (yet)” in the original question, which labeled everything as speculation.

The whole discussion is worth reading and there is a wealth of interesting pointers. Below is the list of links I followed or will follow as soon as I find the time.

• Lively Linear Lisp — ‘Look Ma, No Garbage!’
• ‘Use-Once’ Variables and Linear Objects
• Philip Wadler: Linear Logic
• omake
• Patterns of Software (pdf)
• Psychological criticism of the Prototype-based object-oriented languages
• E
• Partial Evaluation and Automatic Program Generation or pdf
• partial-eval.org
• Partial Evaluation – An Overview

I looked through my logs and was happy to see that some of my older posts are still quite popular. When I reread them I found some minor mistakes and added a little content. Anyway, I updated these three older posts:

• Rails, ActiveRecord and Distributed Ruby (DRb) in a nutshell (added DRb over unix sockets)
• Rubybashing: Why use implicit return? (this reminds me, I wanted to write an article about what I had learned, something like “Why and when to use implicit return in Ruby?”)
• Using Google Talk with kopete

Frank Westphal writes about Barcamp Berlin. This was the first time I heard about a Barcamp but the whole idea sounds like a lot of fun:

The Rules of BarCamp:
BarCamp is an ad-hoc un-conference born from the desire for people to share and learn in an open environment. It is an intense event with discussions, demos and interaction from attendees.

Anyone with something to contribute or with the desire to learn is welcome and invited to join.

When you come, be prepared to share with barcampers.
When you leave, be prepared to share it with the world.

I think I will give it a try, at least some of the topics sound interesting to me:

• Microformats
• Mobile Tagging Matrix
• Web2.0 und Datensicherheit
• Ruby on Rails
• Privatsphäre im offenen Web

I don’t know what I could talk about, but I’m sure I will be able to improvise…

[tags]barcampberlin[/tags]

Some time ago Martin Fowler wrote about Humane Interfaces which led to an lively debate. This is really old stuff, but yesterday I read about the upcoming Java 6 aka Mustang and one of the changes was adding the isEmpty() method to String.

So it seems like Java is slowly getting more humane

This blog is closed for vacation. I will spend the next 2 1/2 weeks far away from any computer hiking through Ireland…

I started working on my RSS filter again. It’s a rewrite of my php test as a small Ruby on Rails app using Bob Aman‘s FeedTools. All the time I was wondering if this is really worth spending my time. To me the idea of filtering feeds seems obvious, but it felt strange that there were no other tools around to provide the same service.

Yesterday I found Feedrinse, so perhaps my idea isn’t strange after all. They provide only very simple features: filter by author, filter by keyword and filter by tag. Not much, but it shows there is a market

At my daytime job I had to rewrite a class which sends a Message to a Queue. Sounds simple? With EJB3 it is reasonably simple and can be done in around 10 lines of code involving lots of lookups. But if you are looking for a reliable solution which works even when the application server reboots every once in a while your code gets messy. My current solution has 120 lines of code and there are still some things to add like buffering of unsent messages. Read the rest of this entry »

The previous post about blog quality made me think about the things I want to write on this blog. Here’s the result, enjoy:

• Thou shall not post daily links – if I’m interested in your links, I will subscribe to your $socialbookmarkingtool feed
• Thou shall not post daily pics – BOCTAOE like [daily dose of imagery]
• Thou shall not write ‘sorry for the lack of posts’ posts – twice in a row is evil, thrice is a mortal sin
• Thou shall publish full feeds – I want to read my stuff from bloglines
• Thou shall finish at least one of your unfinished blog entries before starting a new one – right now I have 8 unfinished posts
• Thou shall add some new content to a quote – “The ability to quote is a serviceable substitute for wit. ~Somerset Maugham“
• Thou shall not join the chorus – I really like rails, but how many people posted this in the last 24h
• Thou shall link to this list and/or add comments with additional commandments – sorry, but I’m out of ideas

I don’t have my own blog, I’m just occasionally posting here on Frank’s blog. This is because I don’t think I have lots of important or relevant ideas to justify the existence of my own blog, nor would I like to invest a lot of time. Now I found a kind of official confirmation for my point of view: Read the rest of this entry »