This post originated from an RSS feed registered with Ruby Buzz by Ryan Davis. Original Post: Best of both worlds 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

Here is my very simple rule for optimizing:

Never ever code for speed until you need to code for speed!

Consider it an addendum to Knuth's "root of all evil" law. There are two corollaries to this law:

Always measure.

and

Only rewrite the slow part in C, not the whole damn thing.

Some of this came up recently because of a dialog last week on ruby-talk between Sascha Ebach and JEG2 about making FasterCSV even faster. James wants to keep the module as pure ruby (totally laudable goal) but Sascha thought it'd be neat to take advantage of RubyInline if it were available. I'm all for keeping it pure ruby, but I wanted to see how you'd do the dual implementation version in a way that still read clean. Here is my first scratch at it:

begin; require 'inline'; rescue LoadError; end

class MaybeFast
  def blah
    puts "slow version"
  end unless respond_to? :inline

  inline do |builder|
    builder.c 'void blah() { puts("fast version"); }'
  end if respond_to? :inline
end

MaybeFast.new.blah