Ranged types are directly from Pascal. You can also use them to specify the valid indexes for an array (so a given array might be zero-based, or one-based, or 1900-based, or even -32768-based). A very positive feature, I agree.
type Character_Histogram is Array (range 'A'..'Z') of Integer;
-- syntax may be off, not enough practice to do this cold right now type
TPerson = record
name: string;
age: integer;
end;
TThrteenPersons = array[10..22] of TPerson;
procedure Check(const aPerson: TPerson);
var
vPerson: TThrteenPersons;
begin
vPerson[11] := aPerson; // this is ok
vPerson[1] := aPerson; // this one gives compile error
end;
Histogram : Character_Histogram;
...
Histogram['A'] := Histogram['A'] + 1;
This modern pascal is very feature rich and has plenty of fancy bells and whistles.
So you can have arrays where the index runs from -10 to +20 or from +7 to +26 for instance. Booleans are also ordinal types so you can have an array where the index is boolean.
type Colors is (Red, Green, Blue, Black, Gray, White);