How-To

Debugging Methods

Using pragmas

function Create(info: Object_Info) return Object is
   part1: --...
   pragma Assert(Is_Valid(part1), "Pragmas can be placed in declarative contexts");
   pragma Debug(Put_Line(info'Image)); -- The `Debug` pragma is a GNAT extension.
   part2: --...
begin
   if Config.Debug then -- Also see the "Conditional Compilation" section
      -- Debugging stuff goes here
   end if;
end Create;

Conditional Compilation

Boolean Constants

if Config.Debug then
   Put_Line("Extra debugging information/checks");
end if;

package Config
   Debug: constant Boolean := True;
end Config;

Separate Subprograms

The Do_Something may then be defined in, for example, my_package-do_something-2022.adb and my_package-do_something-2005.adb to allow for both Ada2022 and Ada2005 implementations of the same subprogram.

procedure Do_Something is separate;

Using GPRBuild (the Naming package), the files that are included into the build may then also be conditional in order to select the correct version:
for Body("My_Package.Do_Something") use "my_package-do_something-2005.ada"; This method works in every situation, such as having separate Windows/Linux/MacOS/etc implementations, but it will be very verbose and may duplicate a lot of code if there are only a few subprograms that need to be swapped out.

Preprocessing

GNAT provides a C-style preprocessor to allow for conditional compilation. For small sections of code it will more easily allow for code reuse without copying and removes the need for separate files. See the GNATPrep page for usage.