# File lib/randexp/reducer.rb, line 24
    def self.literal(cell, quantity = nil)
      case quantity
      when '?''?'         then ([''] + cell).pick
      when :+, '+?''+?'    then raise "Sorry, \"#{cell * ''}+\" is too vague, try setting a range: \"#{cell * ''}{1,3}\""
      when :*, '*?''*?'    then raise "Sorry, \"#{cell * ''}*\" is too vague, try setting a range: \"#{cell * ''}{0,3}\""
      when Range        then quantity.pick.of { cell * '' } * ''
      when Integer      then quantity.of { cell * '' } * ''
      when nil          then cell * ''
      end
    end