type_qualification.adb

来自「This contains the following topics and m」· ADB 代码 · 共 26 行

with Text_IO; use Text_IO;

procedure type_qualification is
   --In some situations an expression's or value's type can be ambiguous.
   --For example,
   type color is new Integer;
   subtype primary is color range 1 .. 20;
   type rainbow is new Integer;
   subtype new_color is rainbow range 1 .. 20;

begin
   --for i in red..blue loop -- this is ambiguous

   -- Here we need to specify precisely what type is required. This is done
   --with type qualification.
   for i in  rainbow'(1) .. rainbow'(5) loop
      -- for i in rainbow'(red)..blue loop -- only one qualification needed
      --for i in primary'(red)..blue loop
      --Type qualification does not change a value's type. It merely informs
      --the compiler of what type the programmer thinks it should be.
      Put_Line ("hai");
   end loop;
   --end loop;
   -- end loop;
end type_qualification;