A Haml :ruby filter that doesn't use locking and doesn't redirect $stdout.

example.haml

:ruby_no_lock
  puts 'This will go to wherever stdout is pointing'
  haml_concat 'This will go into the Haml output'

ruby_no_lock.rb

# require this file after you've required Haml

module Haml::Filters
  module RubyNoLock
    include Base

    def compile(compiler, text)
      return if compiler.options[:suppress_eval]
      compiler.instance_eval do
        push_silent text
      end
    end
  end
  defined['ruby_no_lock'] = RubyNoLock
end