Test1

useless

-module(useless).
-export([polynom/1]).
-import(mochinum).

calculateSum([Head|Tail],Var,Sum,TailLen) ->
  SumRes = case Tail of
      [] -> Sum + Head;
      [_] -> Sum + Head * Var;
      _ -> Sum + Head * math:pow(Var,TailLen)
  end,
  calculateSum( Tail, Var, SumRes, TailLen - 1 );
calculateSum([],_,Sum,_) -> Sum.
  
createPolynom([Head|Tail],Var,ResultString,TailLen) ->
  {Format,Args} = case Tail of
  		    [] when Head > 0 -> 
		      {"+~s",[toStr(Head)]};
		    [] -> 
		      {"~s",[toStr(Head)]};
		    [_] when Head > 0 -> 
		      {"+~s*~s",[toStr(Head),toStr(Var)]};
		    [_] -> 
		      {"~s*~s",[toStr(Head),toStr(Var)]};
		    [_|_] when Head > 0 -> 
		      {"+~s*(~s^~s)",[toStr(Head),toStr(Var),toStr(TailLen)]};
		    [_|_] ->
		      {"~s*(~s^~s)",[toStr(Head),toStr(Var),toStr(TailLen)]}
		  end,
  createPolynom(Tail,Var, ResultString ++ io_lib:format(Format,Args), TailLen - 1);
createPolynom([],_,Str,_) -> Str.
  
toStr(Value) when erlang:is_integer(Value) -> erlang:integer_to_list( Value );
toStr(Value) when erlang:is_float(Value) -> mochinum:digits( Value ).
  
polynom(PolynomIndexes) ->
  fun(Var) -> 
    PolynomTLength = length(PolynomIndexes)-1,
    ReversePolynom = lists:reverse(PolynomIndexes),
    PolynomStr = string:strip(createPolynom(ReversePolynom,Var,"",PolynomTLength),both, $+),
    ResultString = PolynomStr ++ "=" ++ mochinum:digits( calculateSum(ReversePolynom,Var,0,PolynomTLength) ),
    erlang:list_to_bitstring( ResultString )
  end.