aref array reference
bool boolean
const constant
elem element
err error
fh filehandle
func function
href hash reference
int integer
interp interpreter i iterator?
kv key/value
num number
obj object
op operator, operation
r read(able)
ref reference
regex regular expression
expr expression
rw read/write
ro read-only
str string
sub subroutine
w write(able)
in input out output io input/output mem memory os operating system anon anonymous
interestingly, among references there are aref and href, but scalar and subroutine references are not presented.
Vadim