日本語の物語っぽいテキストから登場人物を抽出する (適当)

extract_characters.rb

#!/usr/bin/env ruby
require 'MeCab'
require 'ostruct'
# USAGE:
#   ruby extract_characters.rb < story.txt
# SPEC:
#   副詞可能は「今|今度|今日は」みたいなやつなので省いている
# TODO:
#   each_two_sentences で照応を考慮する
#   一人称っぽい言葉も登場人物としてカウントする
#   Perl の Term::Extract とか参考にして複合語ちゃんと扱う
#  「〜さん|くん|ちゃん|様」等の接尾をとる
# BUG:
#   駆け込み訴えで「人」も抽出されてしまう

class CharacterExtractor
  class ComplexWord
    attr_reader :surface, :nouns
    def initialize(nouns)
      @nouns = nouns
      @surface = @nouns.map {|n| n.surface }.join
    end
  end

  TOPIC_SUFFIX_FEATURE = %r#^助詞,係助詞,\*,\*,\*,\*,は,ハ,ワ$#u
  NOUN_FEATURE         = %r#^名詞,#u
  NOUN_EXCLUDE_FEATURE = %r#^名詞,(接尾|非自立|代名詞|副詞可能)#u
  COMPLEX_NOUN_FEATURE = %r#^(接頭|連体|名)詞#u

  def self.extract(io)
    new.extract(io)
  end

  def extract(io)
    chars = Hash.new(0)
    each_two_sentences(STDIN) do |prev,curr|
      nodes = mecab_nodes(curr) if curr
      next if nodes.nil?
      nodes = parse_complex_nouns(nodes)
      nodes.each_cons(2) do |n, m|
        if (n.is_a?(ComplexWord) || n.feature =~ NOUN_FEATURE && n.feature !~ NOUN_EXCLUDE_FEATURE)
          chars[n.surface] += 1 if m.feature =~ TOPIC_SUFFIX_FEATURE
        end
      end
    end
    sorted = chars.sort_by{|k,v| -v }
  end

  def mecab_nodes(text)
    @tagger ||= MeCab::Tagger.new
    nodes = []
    node = @tagger.parseToNode(text)
    while node = node.next
      nodes << OpenStruct.new(:surface => node.surface, :feature => node.feature)
    end
    nodes
  end

  def each_two_sentences(io)
    prev = nil
    while line = io.gets
      line.chomp!
      line.gsub!(/「(.+?)」/u, '')
      line.gsub!(/　/u, '')
      line.gsub!(/[\(\)]/u, '')
      sentences = line.split(/。/u)
      yield(prev.last, sentences.first) if prev
      sentences.each_cons(2) do |prev,curr|
        yield(prev, curr)
      end
      prev = sentences
    end
  end

  def parse_complex_nouns(nodes)
    buf, res, flg = [], [], false
    nodes.each do |node|
      if node.feature =~ COMPLEX_NOUN_FEATURE
        flg = true
        buf << node
      else
        if flg
          if buf.size == 1
            res << buf.first
          else
            res << ComplexWord.new(buf)
          end
          buf = []
          flg = false
        end
        res << node
      end
    end
    res
  end
end

chars = CharacterExtractor.extract(STDIN)
chars = chars.sort_by{|k, v| -v }
chars[0, 3].each {|k, v| puts k }