quicksilver scoring algorithm in ruby

qs_scoring.rb

#!/usr/local/bin/ruby
# -*- encoding:utf-8 -*-

require 'readline'
require "/Users/keyes/Dropbox/lib/ruby_class_list/rbutils"

class String
  def to_score(abbrev)
    return 0.9 if abbrev.empty?
    return 0.0 if length < abbrev.length

    tail = ""
    loop do
      return 0 if abbrev.empty?
      unless md = match(/#{abbrev}/i)
        abbrev, tail = abbrev.split_at(-1)
        next
      else
        remaining_score = md.post_match.to_score(tail)
        return calc_score(md, remaining_score)
      end
    end
  end

  protected
  def calc_score(md, remaining_score)
    if remaining_score.zero?
      0
    else
      score = (1 * md.to_s.length) + (remaining_score * md.post_match.length)
      if md.pre_match =~ /[\s_#:\.]+$/
        score += 0.85 * (md.pre_match.length - $&.length) + 1 * $&.length
      elsif !md.pre_match.empty? and md.to_s =~ /^[A-Z]/
        score += 0.85 * md.pre_match.gsub(/[A-Z]/, "").length
      end
      score / self.length
    end
  end

  def split_at(index)
    return slice(0...index), ( slice(index..-1) || "" )
  end
end

rb_classes = (RbUtils.classes + RbUtils.modules) - [RbUtils]
rb_public_methods = rb_classes.map do |klass|
  meths = klass.methods_by_type
  meths['public_methods'].map { |m| "#{klass}.#{m}" } +
  meths['public_instance_methods'].map { |m| "#{klass}##{m}" }
end.flatten

rb_classes = (Rbutils.classes + RbUtils.modules) - [Rbutils]

WORDS = rb_public_methods

trap(:INT, "EXIT")

loop do
  abbrev = Readline.readline("> ", true)

  WORDS.inject([]) do |mem, app|
    score = app.to_score(abbrev)
    mem << [score, app] if score > 0.9
    mem
  end
  .sort_by { |score, _| -score }
  .each_with_index { |(score, app), i| printf "%2d:%s (%.4f)\n", i+1, app, score }
end
#while buf = Readline.readline("> ", true)
#  exit(0) if buf =~ /exit/
#
#
#
#  scores = WORDS.map{|i| [i.to_score(buf), i]}.reject{|i| i[0]<0.7}.sort
#  next if scores.empty?
#  
#  items = scores.map{|i| i[1]}
#  Readline::HISTORY.push(*items)
#  if scores.last[0] == 1
#   puts "open -a '#{items.last}'"
#    `open -a "#{items.last}"` 
#  else
#    scores.reverse[0, 20].each {|i| printf("%f %s\n", i[0], i[1])}
#    AppleScript.key_code(126) # 竊台ｸ顔泙蜊ｰ
#  end
#end
#