Useless instructions: Difference between revisions

The Ada compiler produces warnings for many useless constructs. Eliminating all warnings eliminates most useless constructs. If the parameter passing mode for the parameter in procedure Useless is changed to the OUT mode the compiler generates a compiler '''error''' and the actual parameter must be a variable. The value of an OUT parameter must be assigned within the procedure.

Ada syntax is case-insensitive, therefore the programmer cannot create a new identifier which differs from another identifier only by letter case.

<lang Ada>with Ada.Text_IO; use Ada.Text_IO;

procedure Main is

procedure Useless (param : in Integer) is -- compiler warning - "param" not referenced

begin

if True then

null;

else

Put_Line ("Never called"); -- Warning: this code can never be executed and has been deleted

end if;

for I in 2 .. 1 loop -- Compiler warning - loop will not execute

Put_Line ("Never called");

end loop;

while False loop

Put_Line ("Never Called");

end loop;

end Useless;

begin

Useless (0);

Put_Line ("Working OK.");

end Main;</lang>

{{out}}

Working OK.