An Introduction to Ruby2c

Automatic Translation of Ruby Code to C

This is an extract from our keynote presentation / PDF that we have online. If you've already read that, then this will bore you. Otherwise, read on...

The Problem

• Simply put, writing ruby internals in C requires a mental context switch every time you go from ruby to C and back.
• C sucks.
• This makes the internals harder to understand.
• Which makes it harder to recruit otherwise good coders to work on ruby internals.
• Which slows down ruby’s development.

Our Proposal

• Implement the whole thing in ruby, and translate to C.
• No more context switching.
• Able to test changes live in the system.
• More understandable internals.
• More accessible to others.
• Must be in a subset of ruby that is easily translatable to C.

Current Status

We currently have code that can convert the following example code:

  def hello(n)
    1.upto(n) do
      puts "hello world"
    end
  end

into the following C code:

  void
  hello(long n) {
  long temp_var1;
  temp_var1 = 1;
  while (temp_var1 <= n) {
  puts("hello world");
  temp_var1 = temp_var1 + 1;
  }
  }

An Extra Goodie

I wrote a 13 line class and now can do the following:

  class MyTest
    def factorial(n)
      f = 1
      n.downto(2) { |x| f *= x }
      return f
    end
  
    inline(:Ruby) do |builder|
      builder.optimize :factorial
    end
  end

and dynamically replaces the ruby version, in this case, an 8.8x speed-up with zero effort!

Want to Help?

• Know what you are getting into... read the propaganda.
• Respond on my blog, send me email, talk to me on IRC, or contact Eric Hodel.
• A ruby2c subset spec is coming soon.
• Lots to write, and much of it should be fun!