fun string_of_varpow x k = let val term = Thm.term_of x val name =
(case term of
Free (n, _) => n
| _ => error "Term in monomial not free variable") in if k = 1 then name else name ^ "^" ^ string_of_int k end
fun string_of_monomial m = if FuncUtil.Ctermfunc.is_empty m then"1" else let val m' = FuncUtil.dest_monomial m val vps = fold_rev (fn (x,k) => cons (string_of_varpow x k)) m' [] in foldr1 (fn (s, t) => s ^ "*" ^ t) vps end
fun string_of_cmonomial (m,c) = if FuncUtil.Ctermfunc.is_empty m then Rat.string_of_rat c elseif c = @1 then string_of_monomial m else Rat.string_of_rat c ^ "*" ^ string_of_monomial m
fun string_of_poly p = if FuncUtil.Monomialfunc.is_empty p then"0" else let val cms = map string_of_cmonomial
(sort (prod_ord FuncUtil.monomial_order (K EQUAL)) (FuncUtil.Monomialfunc.dest p)) in foldr1 (fn (t1, t2) => t1 ^ " + " ^ t2) cms end
val number =
Scan.repeat1 (Scan.one Symbol.is_ascii_digit >> (fn s => ord s - ord"0"))
>> foldl1 (fn (n, d) => n * 10 + d)
val nat = number val int = Scan.optional (str "~" >> K ~1) 1 -- nat >> op * val rat = int --| str "/" -- int >> Rat.make val rat_int = rat || int >> Rat.of_int
(* polynomial parsers *)
fun repeat_sep s f = f ::: Scan.repeat (str s |-- f)
val parse_id = Scan.one Symbol.is_letter ::: Scan.many Symbol.is_letdig >> implode
