Object-oriented Software in Ada 95

312 A Text user interface
22.2 API for TUI
The API (Application Program Interface) for the TUI consists of a set of function and procedure calls. These are
implemented as methods in the classes used to form the complete TUI interface. These window classes form an
inheritance hierarchy illustrated in Figure 22.1.
Window
Menu
Dialog
Title_Menu
Figure 22.1 Window hierarchy.
The API calls for a Window are inherited to form the base API calls for a Menu and Dialog. Likewise, the
base API calls for a Title_Menu are inherited from a Menu.
22.2.1 To set up and close down the TUI
The following procedures are responsible for setting up and closing down the TUI system. These API calls are
independent of any window and thus do not require as a parameter an actual instance of a window. These methods
are class methods of the class Input_manager.
function / procedure
Window_Prolog;
Window_Start;
Window_Epilog;
Note
Set up the environment for the TUI. This must be called
outside the block in which windows are elaborated.
After initializing any program-generated windows, start the
application by allowing a user to interact with the program.
Close down the window system. This must be called
outside the block in which the windows are elaborated.
For example, the structure of a program using the TUI is:
procedure Main is
begin
Window_Prologue;
declare
begin
Window_Start;
end;
Window_Epilog;
end Main;
-- Set-up window system
-- Declaration of windows used in
-- the program
-- Initialization of windows
-- used in program
-- Start the user interaction
-- Close window system
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