There actually is an array in any POSIX shell. You get one array per file/function. It just feels bad to use it. You can abuse 'set -- 1 2 3 4' to act as a proper array. You can then use 'for' without 'in' to iterate over it.

for i; do echo $i; done.

Use shift to pop items off.

If I really have to use something more complex, I'll reach for mkfifo instead so I can guarantee the data can only be consumed once without manipulating entries.