This post originated from an RSS feed registered with Ruby Buzz by Ryan Davis. Original Post: RubyToRuby Feed Title: Polishing Ruby Feed URL: http://blog.zenspider.com/index.rdf Feed Description: Musings on Ruby and the Ruby Community... Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Ryan Davis Latest Posts From Polishing Ruby

So... drbrain comes up to me in an IM and says flgr is saying it'd be really cool if you could ask a method for its source. I know what he is doing, baiting me like that, but I play along anyways to see what the outcome is like. drbrain and I talked about it and thought it'd be really cool if our ruby2c system added a to_c method to the Method class. That isn't hard at all really, so we added:

class Method
  # with_class_and_method_name is a silly method.
  # Implementation is an exercise for the reader.

  def to_sexp
    with_class_and_method_name do |klass, method|
      ParseTree.new.parse_tree_for_method(klass, method)
    end
  end

  def to_c
    with_class_and_method_name do |klass, method|
      RubyToC.translate(klass, method)
    end
  end
end

But the question came up... can we do this to display ruby code? The answer is yes, and it only took me about 30 minutes to get the proof of concept up and running. First, the example code:

class Example
  def example(arg1)
    return "Blah: " + arg1.to_s
  end
end

e = Example.new
puts "sexp:"
p e.method(:example).to_sexp
puts "C:"
puts e.method(:example).to_c
puts "Ruby:"
puts e.method(:example).to_ruby

and now the output:

sexp:
[:defn, :example, [:scope, [:block, [:args, :arg1], [:return, [:call, [:str, "Blah: "], :+, [:array, [:call, [:lvar, :arg1], :to_s]]]]]]]
C:
str
example(long arg1) {
return strcat("Blah: ", to_s(arg1));
}
Ruby:
def example(arg1)
return "Blah: " + arg1.to_s
end

Cool huh? I can now translate any method to C or get the ruby code for it (sans-comments unfortunately) simply by calling to_c or to_ruby on the method itself!