As far as I’m aware – there’s no C required to run ruby on rails applications¹. Rails is 100% ruby – aka Ruby extended in Ruby. It might be that thats not the kind of extension he’s talking about – and in fact it’s not – he gives a Ruby example of the problem he’s talking about – creating a custom array subclass. Here’s an example of his code in C#.

public class MyArray : Array {} //error CS0644: 'MyArray' cannot derive from special class 'System.Array'


• You can’t extend C# (or Java) in the way he’s trying to in Ruby.
• You can’t add methods to java.lang.Object or System.Object – although extension methods in C# 3.0 will let you add behaviour – but not state.
• You can’t modify the language syntax, add keywords etc… (no macro like features) the way you can in LISP or smalltalk.

Conclusion: C#/Java (well – the JVM/CLR) are not turtles all the way down. In fact – Ruby is more deep turtle wise than C# or Java (ruby supports modules/mixins which are somewhat like extension methods in C# 3.0).

Update: Ayende likes what Avi says – looks like we might not agree on this.

1. I’m aware mongrel – a http server which is used for serving rails apps – has pieces written in C. This is equivalent to IIS for ASP.NET apps (and webrick == casinni – the VS.NET built in webserver vs Ruby’s pure Ruby webserver).

1. Giles Bowkett made an interesting post on his blog:
   

   “[T]his has always been my fear for Rails; that in five to ten years, the worst jobs you could get will be Rails jobs where you’re maintaining stuff built by non-programmers who figured Rails made programming so easy that they didn’t really need to understand what they were doing.”

2. In Avi Bryant‘s ETech presentation Applied Web Heresies (slides) he makes the following statement:
   

   “Meaningful URLs don’t carry enough meaning
   Names make me think too much
   DRY (not everything is an API)”

This is reminiscent of Visual Basic (and VBA, Access etc..). I know I’ve done maintenance on some scary code which was written by someone who didn’t understand enough about what they were doing.

Not Everything is an API

The obsession of Rails dudes with making every object a REST endpoint is a particularly scary form of religion. In VB6 every “class” was exposed as a COM object. For those of you who are not familiar with COM – this means that every public class in your application was exposed as an API. Weather you wanted it available to other applications or not. As you can imagine – this resulted in some truly monstrous misuse of parts of applications by other applications and lead to the worst kind of spaghetti dependencies imaginable (circular build dependencies etc).

In general API’s should be carefully thought through, designed and exposed as a separate development exercise from building a web application. For example:

1. Google maps was released
2. People started hacking mashups using it.
3. The GMaps team went away and designed a JavaScript api which is:
   • versioned
   • licenced
   • secure
   • supportable