-- Universal_Integer is actually implicit, but here is its explicit definition
type Universal_Integer is range -Infinity to Infinity;

-- 1) Standard integers types

type Integer is new Universal_Integer range <impl. defined> to <impl. defined>;
subtype Natural is Integer range 0 to Integer'High;
subtype Positive is Natural range 1 to Natural'High;

-- The following will be put in a separate package in order to keep backward
-- compatibility with code using numeric_std.

-- 2) Binary integers types
-- The difference with standard integers is that they will be represented
-- in bits which implies that they have an extra size property available to define
-- their size in bits. Except for modulo integers, overflowing the range is also
-- forbidden just as standard integers.

type Binary_Integer is new Universal_Integer with Binary => True;

-- 2.1) Signed / unsigned integers types

type Signed is new Binary_Integer;
type Unsigned is new Binary_Integer range 0 to Binary_Integer'High;

-- 2.2) Modulo integers types
-- Overflows don't raise an error but a modulo operation will be made instead

type Modulo_Integer is new Binary_Integer with Modulo => True;

-- 2.2.1) Signed / unsigned integers modulo types
-- We could possibly replace «(Un)signed'Low to (Un)signed'High» by
-- (Un)signed'Range if we first make that legal just as it is in Ada.
type Mod_Unsigned is new Modulo_Integer range Unsigned'Low to Unsigned'High;
type Mod_Signed is new Modulo_Integer range Signed'Low to Signed'High;