link strings

procedure main()
   local expr, result, term, i, var, letters, sequence, k

   expr := ""

   # Read Mathematica expression.

   while expr ||:= read() 

   #  Delete extraneous characters.

   expr := deletec(expr, '()\\! ')

   #  Analyze polynomial

   sequence := ""

   #  Parse expression.

   expr ? {
      while term := tab(upto('+-
') | 0) do    # get term
         term ? {
            result := ""
            i := (tab(many(&digits)) | 1)	  # multiplier
            while var := move(1) do {	  # variable
               if ="^" then k := tab(many(&digits))
                   else k := 1
               result ||:= repl(var, k)
               }
            sequence ||:= repl(result, i)
            }
         move(1) | break
         }
      }

   letters := &lcase ** sequence        #variables

   #  Map variables into digits (assumes at most
   #   nine variables).

   write(map(sequence, letters,
      "123456789"[1 +: *letters]))

end