Last night Zed Shaws Rails is a Ghetto Shitstorm was brought to my attention. Zeds rant provides enough meat for a post of its own but it’s not what I want to write about today. Following some comments on Zed article on Technorati I stumbled (again) into one of those evenings full of great discoveries.
Shortly before Git became really popular some months ago, I had become interested in darcs and distributed revision control systems in general. The topic is kinda difficult though and none of the texts I was reading at the time could really communicate the benefits of DRCS to me. I always had some gripes about svn but it wasn’t clear to me how DRCS were able to solve them.
I lost interest, following posts about git only loosely until last night a colleague pointed me to Randal Schwartz’ Git presentation at Google Tech Talks. Holy crap, I need to check this out. What appeals most to me:
The ability to have the entire repository available locally
I was extremely sceptical when I first heard about this, but when Schwartz claimed that the entire repository of the linux kernel is half the size of a checkout I was sold.
Didn’t know about this before. Makes the transition much easier.
Having local-only repositories inside your working dir
I have many smaller projects that I’d love to keep locally contained. In Subversion I always had to create a repository on my server for everything.
Other small things
High compression, the simple database system behind git, the optimization for speed, staged commits, the ability to completely erase files from a repository (e.g. stuff not intended for publication, something that was very hard to do on subversion), the placement of all metadata in a single directory (opposed to littering every dir in the working copy with
Despite some shortcomings that was enough to make me install git on my mac (
sudo port install git-core). I’m eager to check it out later today.
Smalltalk and Seaside
Ever since watching Evan Phoenix Rubinius Presentation at RubyConf 2007 and listening to Avi Bryants Smalltalk’s Lessons for Ruby Keynote from RailsConf 2007 I’ve been curious about Smalltalk. I mean, I was curious about it before, after all it’s probably the language that has the most influence on what I’m doing today (through its promotion of object-orientation and through providing key principles behind ruby), but since listening to Avi and Evan I’ve become really interested in VM implementations (see Smalltalk-80: The Language and Its Implementation for an excellent in-depth description of the orignal Smalltalk-80 interpreter) and real world usage of smalltalk.
To be honest, as much as I love Ruby as a language, its implementations all suck. And Evan explained why: Implementing most of the base language on another Platform (C for MRI, Java for JRuby) turns out to be a leaky abstraction when you want to extend the language. Additionally, as pure and beautiful the Ruby language is in concept, as ugly is its implementation. On the one hand, what I like so much about Ruby is its conceptual purity, its very limited set of axioms, syntax and exceptions from its own rules, on the other hand, this purity is not present in the interpreter when high-level data structures (like arrays and hashes) are implemented in C for performance reasons. Smalltalk has always had a strong philosophy of implementing as much as possible in Smalltalk itself and only resorting to C for a minimal subset (“Turtles all the way down”).
Rubinius aims to implement a Ruby interpreter on the design principles of smalltalk. I love the project and there seem to be only the most brilliant people working on it (Evan Phoenix, Eric Hodel, Ryan Davis and others, full time). As many others have said already, Rubinius is likely to become the main Ruby implementation if they manage to take off (and they will undoubtedly).
Yet, something was bugging me: If Ruby and Smalltalk are so similar, if Smalltalk has been around, specified and stable for 25 years in many different, compatible implementations, commercial and open source, why take the long route and bend Ruby to look like Smalltalk? Why not use Smalltalk directly? These questions became even more nagging after reading Randal Schwartz’ (yeah, the guy who sold me on Git earlier) Transcript show: ‘Hello, world!’, cr and Fabio Akitas excellent Interview with Avi Bryant (part 1, part 2). Listening to yet another chat with Avi (linked in the second part of Fabio’s interview) at Floss Weekly (with Randal Schwartz again, highly recommended) before falling asleep I finally decided to check out Squeak, the (most popular?) opensource Smalltalk implementation. I was amazed at the simplicity of the installation: Download the VM, Download the Squeak image, load the image into the VM, done.
I have read about Seaside, Avi’s web development framework, before, mainly in reagard to it’s clever use of continuations, but some of the stuff he described at Floss sound almost too good to be true. Live debugging of your app in the browser ? With hot code swapping over the wire? And I thought Rails’ rdebug integration was great.
Well, at 2am I was finally falling asleep but the stuff I’ve been discovering will probably keep me occupied for quite some time. As I explore and discover more about the topics mentioned, I’ll report my findings here on my blog.