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 `\seq_push:Nn`. 2. Should there be a higher level interface for stacks of the different data types in `expl3`? Best Jonathan