guideline

Use subprograms to enhance abstraction.

Restrict each subprogram to the performance of a single action.

Your program is required to draw a menu of user options as part of a menu-driven user interface package. Because the contents of the menu can vary depending on the user state, the proper way to do this is to write a subprogram to draw the menu. This way, the output subprogram has one purpose and the way to determine the menu content is described elsewhere.

...
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procedure Draw_Menu
      (Title   : in    String;
       Options : in    Menu) is
   ...
begin  -- Draw_Menu
   Ada.Text_IO.New_Page;
   Ada.Text_IO.New_Line;
   Ada.Text_IO.Set_Col (Right_Column);
   Ada.Text_IO.Put_Line (Title);
   Ada.Text_IO.New_Line;
   for Choice in Alpha_Numeric loop
     if Options (Choice) /= Empty_Line then
         Valid_Option (Choice) := True;
         Ada.Text_IO.Set_Col (Left_Column);
         Ada.Text_IO.Put (Choice & " -- ");
         Ada.Text_IO.Put_Line (Options (Choice));
     end if;
     ...
   end loop;
end Draw_Menu;
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rationale

Subprograms are an extremely effective and well-understood abstraction technique. Subprograms increase program readability by hiding the details of a particular activity. It is not necessary that a subprogram be called more than once to justify its existence.

notes