Calculate & display the differences among multiple files.

codegene.rb

#!/usr/bin/env ruby

# Requirements:
#  Ruby1.9
#  gem 'ansi'
#  gem 'text_layout'
#  diff
#  diffstat

require 'shellwords'
require 'ansi'
require 'text_layout'


class String
  alias display_width_without_ansi display_width

  def display_width
    method(:display_width_without_ansi).unbind.bind(ANSI.unansi self).call
  end
end

Filename = Struct.new :name, :index

class Diff < Struct.new(:inserted, :deleted, :modified)
  def display_text(flag=true)
    r = []
    r << ANSI.color(inserted.to_s, flag ? :green : :red) unless inserted.zero?
    r << ANSI.color(deleted.to_s, flag ? :red : :green) unless deleted.zero?
    r.reverse! unless flag
    r << modified.to_s unless modified.zero?
    r.join("/")
  end
end

files = ARGF.enum_for.map.with_index{|line, i| Filename.new line.strip, i}
r = Array.new(files.size){[]}

files.combination(2).each do |f1, f2|
  diff = Diff.new(*`diff --strip-trailing-cr -du #{Shellwords.shellescape f1.name} #{Shellwords.shellescape f2.name} | diffstat -mt`.lines.to_a.last.split(",").map{|v|Integer(v) rescue 0}[0,3])
  r[f1.index][f2.index] = diff.display_text(true)
  r[f2.index][f1.index] = diff.display_text(false)
end

files.each do |file|
  r[file.index][files.size] = {value:file.name, align: :left}
end

puts TextLayout::Table.new(r).layout