Note that var has NOT acquired the "-i" (integer) attribute, despite
having been assigned a number value.
I noticed that myself. I expect that all this goes back to ancient
history -- arithmetic would have been an add-on at some point and
integers were never robustly typed, just scalars subject to special
processing, so ' $(( )) ' says: "treat me mathematically, even tho
I'm otherwise just a scalar". But in my previous post it would seem
that 'abc' IS an integer because it increments like one, but even
then typeset -p shows it as scalar. It starts as a string assigned
to 'var' but it would seem it gets 'promoted' to an integer
variable.