Definition: two scalar values separated by two consecutive periods

Notes: (1 .. 5)            # same as (1, 2, 3, 4, 5)
(1.2 .. 5.2)        # same as (1.2, 2.2, 3.2, 4.2, 5.2)
(2 .. 6,10,12)      # same as (2,3,4,5,6,10,12)
($a .. $b)          # range determined by current values of $a and $b