translate (REXML::Functions)

    # File temp/functions.rb, line 228
        def Functions::translate( string, tr1, tr2 )
          from = string(tr1)
          to = string(tr2)

          # the map is our translation table.
          #
          # if a character occurs more than once in the
          # from string then we ignore the second &
          # subsequent mappings
          #
          # if a charactcer maps to nil then we delete it
          # in the output.  This happens if the from
          # string is longer than the to string
          #
          # there's nothing about - or ^ being special in
          # http://www.w3.org/TR/xpath#function-translate
          # so we don't build ranges or negated classes

          map = Hash.new
          0.upto(from.length - 1) { |pos|
            from_char = from[pos]
            unless map.has_key? from_char
              map[from_char] =
              if pos < to.length
                to[pos]
              else
                nil
              end
            end
          }

          string(string).unpack('U*').collect { |c|
            if map.has_key? c then map[c] else c end
          }.compact.pack('U*')
        end