anchor.diff:  
     /// The type of this token.
     final TokenType type;
  +  int argCount = 0;
   
     /// Creates a new Token with the given text and type.
     Token(this.text, this.type);
  
positive.code:           currExpr = Sgn(exprStack.removeLast());
            break;
          case TokenType.FUNC:
            currExpr = GenericFunction(currToken.text, exprStack, genericFunctionHandlers[currToken.text]);
            exprStack.clear();
            break;
          default:
            throw FormatException('Unsupported token: $currToken');
  
negative.code: 
        // If the current Token is a function, put it onto the operator stack.
        if (curToken.type.function) {
          curToken.argCount = 1;
          operatorBuffer.add(curToken);
          prevToken = curToken;
          continue;
  