Change _vector declarations to use integer as range rather than natural

Currently, all _vectors are declared like this :

type integer_vector is array(natural range <>) of integer;

I would like this changed to:

type integer_vector is array(integer range <>) of integer;

Why is this important?

OSVVM RandomPType has a DistInt function that takes an integer_vector of weights. Because natural is used for the range, only +ve numbers can be generated. If I want to generate a distrubution from -10 to +10, I would currently have to do this:

-- Distribute around 10, 10 = 80%, all others 1%
constant my_dist : integer_vector(0 to 20) => (10 => 80, others => 1);
constant x       : integer;

...

x := rand.DistInt(my_dist);
x := x - 10;                 -- normalise -10 to +10

If integer vector was already declared with an integer range, the normalisation above would not be an issue.

I cannot see this being a problem with backwards compatability?

Types I would expect to support it:

• all _vector in std.standard
• std_logic_vector in ieee.std_logic_1164

Type to remain as natural range <>

• Unsigned/signed in numeric_std/bit