project prostringy is
   type Mode_Type is ("debug", "release");  --  all possible values
   Mode : Mode_Type := external ("mode", "debug"); -- a typed variable

   for Source_Dirs use ("src/**");

   case Mode is
      when "debug" => for Object_Dir use "debug/obj";
      when "release" =>  for Object_Dir use "release/obj";
   end case;

   case Mode is
      when "debug" => for Exec_Dir use "debug";
      when "release" => for Exec_Dir use "release"; -- "." means this directory
   end case;

   for Main use ("packdemo");

   package Compiler is
      case Mode is
         when "debug" => for Default_Switches ("ada") use ("-gnat12", "-g");
         when "release" => for Switches ("Ada") use ("-O2"); --s ? -- s generate assembler
      end case;
      --for Local_Configuration_Pragmas use "src/pragmas";
   end Compiler;

   package Builder is
      case Mode is
         when "debug" => for Default_Switches ("ada") use ("-gnat12", "-g");
         when "release" => for Switches ("Ada") use ("-O2");
      end case;
   end Builder;

   package Linker is
      case Mode is
         when "debug" => for Default_Switches ("ada") use ("-gnat12", "-g");
         when "release" => for Switches ("Ada") use ("-O2");
      end case;
   end Linker;

end prostringy;