Forums Developers stacks/pipes?

Does mirc have stacks/pipes or however you would call this? What I mean is:

put test01 to stack
put test02 to stack
put test03 to stack
...

two ideas:

the "classical" stack:
1. read stack; stack = test03
2. read stack; stack = test02
...
(first in = last out)

or
a "pipe"?

1. read stack, stack = test01
2. read stack, stack = test02
...
(first in = first out)

Does mirc have such functions?

And btw, does mirc have the possibility to execute an external program (yes, I know - it has) AND wait until that task closes?

Online's snipplet maybe of use: http://www.mircscripts.org/comments.php?id=1797

As for a FIFO or FILO Stack, you could create one with either variables, or a hash table. Things like Push, Pull, or Peek are easily scripted.