Redis+trie auto complete Ruby program is a copy from http://stackoverflow.com/questions/1958005/redis-autocomplete, authored by Alex. http://en.wikipedia.org/wiki/Trie

gistfile1.txt

require 'rubygems'
require 'redis'
 
class RedisTrie
  TERMINAL = '+'
 
  def initialize(prefix)
    @prefix = prefix
    @r = Redis.new
  end
 
  def add_word(word)
    w = word.gsub(/[^a-zA-Z0-9_-]/, '')
    key = "#{@prefix}:"
 
    w.each_char do |c|
      @r.zadd key, c.bytes.first, c
      key += c
    end
 
    @r.zadd key, 0, TERMINAL
  end
 
  def add_words(*words)
    words.flatten.compact.each {|word| add_word word}
  end
 
  def suggest(text)
    @r.zrange("#{@prefix}:#{text}", 0, -1).map do |c|
      (c == TERMINAL) ? text : suggest(text + c)
    end.flatten
  end
end
 
rt = RedisTrie.new('trie')
 
rt.add_words %w( apple automobile carwash oil-change cranky five ruthie axe auto                                                                   )
 
p rt.suggest(ARGV.shift.to_s)