sort_yaml.rb

#!/usr/bin/env ruby

require 'yaml'
require 'active_support/all'

class Hash
  def to_hash_recursive
    result = self.to_hash

    result.each do |key, value|
      case value
        when Hash
          result[key] = value.to_hash_recursive
        when Array
          result[key] = value.to_hash_recursive
      end
    end

    result
  end

  def sort_by_key(recursive = false, &block)
    self.keys.sort(&block).reduce({}) do |seed, key|
      seed[key] = self[key]
      if recursive && seed[key].is_a?(Hash)
        seed[key] = seed[key].sort_by_key(true, &block)
      end
      seed
    end
  end
end

class Array
  def to_hash_recursive
    result = self

    result.each_with_index do |value,i|
      case value
        when Hash
          result[i] = value.to_hash_recursive
        when Array
          result[i] = value.to_hash_recursive
      end
    end

    result
  end
end



file = ARGV[0]
if File.exists?(file)
  yaml = YAML.load_file(file)

  File.open(file, "w", encoding: "utf-8") do |f|
    # Rails
    # I18n.backend.load_translations
    # default_locale_translations = I18n.backend.send(:translations)[locale].with_indifferent_access.to_hash_recursive
    # i18n_yaml = {locale.to_s => default_locale_translations}.sort_by_key(true).to_yaml

    # sort alphabetically:
    i18n_yaml = yaml.with_indifferent_access.to_hash_recursive.sort_by_key(true).to_yaml
    process = i18n_yaml.split(/\n/).reject{|e| e == ''}[1..-1]  # remove "---" from first line in yaml
    # add an empty line if yaml tree level changes by 2 or more
    tmp_ary = []
    process.each_with_index do |line, idx|
      tmp_ary << line
      unless process[idx+1].nil?
        this_line_spcs = line.match(/\A\s*/)[0].length
        next_line_spcs = process[idx+1].match(/\A\s*/)[0].length
        tmp_ary << '' if next_line_spcs - this_line_spcs < -2
      end
    end
    output = tmp_ary * "\n"
    f.puts output
  end
end