How to best make a custom range?

[Andrew Shvets <andrew.shvets@gmail.com>]

Lets say I have the following code:

subtype Test_Char is Character range ‘A’ .. ‘Z’;

But what if I wanted to include ‘&’, ‘@‘ and ‘?’ in this custom range of characters as well?  I thought of doing the following, but this obviously failed:

subtype Test_Char is Character range ‘@‘ | ‘&’ | ‘?’ | ‘A’ .. ‘Z’;

Or is this impossible unless I use a different approach?