partials.rb

# stolen from http://github.com/cschneid/irclogger/blob/master/lib/partials.rb
#   and made a lot more robust by me
# this implementation uses erb by default. if you want to use any other template mechanism
#   then replace `erb` on line 13 and line 17 with `haml` or whatever 
module Sinatra::Partials
  def partial(template, *args)
    template_array = template.to_s.split('/')
    template = template_array[0..-2].join('/') + "/_#{template_array[-1]}"
    options = args.last.is_a?(Hash) ? args.pop : {}
    options.merge!(:layout => false)
    locals = options[:locals] || {}
    if collection = options.delete(:collection) then
      collection.inject([]) do |buffer, member|
        buffer << erb(:"#{template}", options.merge(:layout =>
        false, :locals => {template_array[-1].to_sym => member}.merge(locals)))
      end.join("\n")
    else
      erb(:"#{template}", options)
    end
  end
end

Excellent! I will be switching my current project over to using the gem. Thanks for all of the great work!