generic to 0 or 1

OK, what I'm hearing is that I need a function
to make the conversion.

I do need a natural because I use it
as an argument in various arrays. I believe,
that a boolean wouldn't work as an argument
for an array.

Why not? Not if you're trying to index into
a std_logic_vector, of course, but if you can
make a custom array type then it's perfectly
OK for the subscript to be a boolean. Suppose,
for example, you wanted to have an array of
two integers indexed by boolean.

type my_array_type is
array (boolean) of integer;

signal chooser: my_array_type;
signal result: integer;
...

chooser(TRUE) <= 55;
chooser(FALSE) <= 100;
...
result <= chooser(A >= B);
-- result=55 if A>=B, result=100 if not.

Any boolean expression will do as the subscript.
Nice, or what?
--
Jonathan Bromley