module ActiveSupport::Multibyte::Unicode

def unpack_graphemes(string)

Unicode.unpack_graphemes('Café') # => [[67], [97], [102], [233]]
Unicode.unpack_graphemes('क्षि') # => [[2325, 2381], [2359], [2367]]

lists.
Unpack the string at grapheme boundaries. Returns a list of character 
def unpack_graphemes(string)
  codepoints = string.codepoints.to_a
  unpacked = []
  pos = 0
  marker = 0
  eoc = codepoints.length
  while(pos < eoc)
    pos += 1
    previous = codepoints[pos-1]
    current = codepoints[pos]
    should_break =
      # GB3. CR X LF
      if previous == database.boundary[:cr] and current == database.boundary[:lf]
        false
      # GB4. (Control|CR|LF) ÷
      elsif previous and in_char_class?(previous, [:control,:cr,:lf])
        true
      # GB5. ÷ (Control|CR|LF)
      elsif in_char_class?(current, [:control,:cr,:lf])
        true
      # GB6. L X (L|V|LV|LVT)
      elsif database.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt])
        false
      # GB7. (LV|V) X (V|T)
      elsif in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t])
        false
      # GB8. (LVT|T) X (T)
      elsif in_char_class?(previous, [:lvt,:t]) and database.boundary[:t] === current
        false
      # GB8a. Regional_Indicator X Regional_Indicator
      elsif database.boundary[:regional_indicator] === previous and database.boundary[:regional_indicator] === current
        false
      # GB9. X Extend
      elsif database.boundary[:extend] === current
        false
      # GB9a. X SpacingMark
      elsif database.boundary[:spacingmark] === current
        false
      # GB9b. Prepend X
      elsif database.boundary[:prepend] === previous
        false
      # GB10. Any ÷ Any
      else
        true
      end
    if should_break
      unpacked << codepoints[marker..pos-1]
      marker = pos
    end
  end
  unpacked
end