concept code of NanoTable

gistfile1.rb

require 'rbtree'

class Nano
  class Pivot
    def initialize(ary)
      @ary = ary
    end
  end

  class Prefix < Pivot
    def <=>(ary)
      it = @ary <=> ary
      return it if it >= 0
      return 1 if ary[0,@ary.size] == @ary
      return -1
    end
  end

  class Forward < Prefix
    def <=>(ary)
      it = super(ary)
      (it == 0) ? 1 : it
    end
  end

  def initialize
    @tree = MultiRBTree.new
  end

  def fetch(ary)
    if block_given?
      @tree.bound(ary, Prefix.new(ary)) do |k, v|
        yield(k)
      end
    else
      result = []
      fetch(ary) {|it| result << it}
      result
    end
  end

  def forward(ary)
    it ,= @tree.lower_bound(Forward.new(ary))
    it
  end

  def store(ary)
    @tree.store(ary, true)
  end
end

nano = Nano.new

# build revert-index
while line = gets
  line.scan(/\w+/) do |word|
    nano.store([word, ARGF.filename, ARGF.file.lineno])
  end
end

# retrieve index
nano.fetch(['def']) do |it|
  p it
end

# each word
word = ''
while word
  word ,= nano.forward([word])
  p word if word
end

# each word, doc
word, doc = ''
while word
  word, doc = nano.forward([word, doc])
  p [word, doc] if word
end