Viivi Input-Port Window

[NOTE]
The correct terminating condition in the algorithm for the factorial calculation should be (= n 0).
To say the truth, Viivi currently has a Problem.
I wrote a sample code in order to explain and ask the problem, including a modified condition (= n 1), and made a mistake to use the code directly for creating the figure.
The condition in the figure will be corrected in the next update.
I apologize for any inconvenience this may cause to you.

The Viivi input-port windows have dark-blue backgrounds by default, together with line-number fields on the left-side.

Every input-port has its own input-port window, and the window shows the contents input from the input-port.

Contents input from the keyboard will be shown in the standard-input-port window #<input-port-window:[standard]>.
Contents input from "/dev/stdin" and "STDIN" on the respective platforms will be shown in the general input-port window #<input-port-window:System.in> with "System.in" as the input-port target.

The user cannot edit the contents displayed on the input-port windows.
To edit the source-files, please use a favorite editor.
Viivi IDE does not have built-in editors.

For an input-port window for a file input-port, all of the contents in the file will be loaded in the input-port window when the file is open.
For an input-port window for a interactive input-port (such as the keyboard, "/dev/stdin", or "STDIN") or a network-port, the contents in the window will be appended with the new input every-time.

After an input-port is closed, the corresponding input-port window keeps open.