danish_norwegian_sort_order.rb

# -*- coding: utf-8 -*-
#
# Danish norwegian sort order. Requires ruby 1.9 or better.

class String
  # compares two strings based on a given alphabet
  def cmp_loc(other, alphabet)
    order = Hash[alphabet.each_char.with_index.to_a]

    self.chars.zip(other.chars) do |c1, c2|
      cc = (order[c1] || -1) <=> (order[c2] || -1)
      return cc unless cc == 0
    end
    return self.size <=> other.size
  end
end

class Array
  # sorts an array of strings based on a given alphabet
  def sort_loc(alphabet)
    self.sort{|s1, s2| s1.cmp_loc(s2, alphabet)}
  end
end

ALPHABETS = {
  :danish_norwegian => 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpqRrSsTtUuVvWwXxYyZzÆæØøÅå',
  :english => 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpqRrSsTtUuVvWwXxYyZzÆæØøÅå'
}

array_to_sort = ['abc', 'abd', 'øøø', 'Æææ', 'Øøø', 'bcd', 'Ååå', 'bcde', 'bde']

p array_to_sort.sort_loc(ALPHABETS[:danish_norwegian])
#=>["abc", "abd", "bcd", "bcde", "bde", "Æææ", "Øøø", "øøø", "Ååå"]