Hi all,

I got two little questions concerning stacks in `expl3`.

1. What is the best way to build a stack for a sequence?

The naive way would be to use something like

    \seq_push:No \l_my_stack_seq \l_my_seq

to push and then

    \seq_pop:NN \l_my_stack_seq \l_my_seq

But this doesn't look like a clean usage of `\seq_pop:NN` and

2. Should there be a higher level interface for stacks of the different
data types in `expl3`?