The most significant update in this release is that you can now alter the
scoring, thereby altering the ordering of search results. A great application of
this is that you can now change the weight of a document based on its age. In
this example we have 365 day half life, ie a year-old document has half the
weight of a new document and twice the weight of a 2-year-old document;

    require 'ferret'

    age_weight = lambda do |doc, score, searcher|
      age = (Date.today - Date.parse(searcher[doc][:date])).to_i
      1 / 2 ** (age.to_f/365)
    end

    index = Ferret::I.new

    sales = [
      { :artist => 'Giovanni Bellini',
        :date => '2006-10-23',
        :work => 'Transfiguration'
      },
      { :artist => 'Giovanni Bellini',
        :date => '2008-01-05',
        :work => 'Pesaro Altarpiece'
      },
      { :artist => 'Gentile Bellini',
        :date => '2008-02-10',
        :work => 'St. Dominic'
      },
    ].each {|doc| index << doc}

    puts index.search('artist:(Giovanni Bellini)').to_s(:work)
    # =>
    #   TopDocs: total_hits = 3, max_score = 0.767351 [
    #           0 "Transfiguration": 0.767351
    #           1 "Pesaro Altarpiece": 0.767351
    #           2 "St. Dominic": 0.129147
    #   ]

    puts index.search('artist:(Giovanni Bellini)',
                      :filter_proc => age_weight).to_s(:work)
    # =>
    #   TopDocs: total_hits = 3, max_score = 0.718006 [
    #           1 "Pesaro Altarpiece": 0.718006
    #           0 "Transfiguration": 0.311937
    #           2 "St. Dominic": 0.129147
    #   ]

You can also now write your own C extensions to filter the search results. You
can see an example of this by downloading the source and looking at;

    ferret_unzipped/ruby/examples/c_extensions/age_filter/

Alternatively, you can view the code at;

    http://ferret.davebalmain.com/trac/browser/trunk/ruby/examples/c_extensions?rev=828

Also, good news for Norwegians, Romanians, Turks and Finns. We now have 3 new
stemmers for Norwegian, Romanian and Turkish and 2 new stop-word lists for
Finnish and Hungarian. Please try them out and let me know if there are any
problems.
