Hi, On Mon, 2019-04-01 at 13:05 +0200, Bruno Le Floch wrote: > Other option: use an xparse environment with "o" signature as you are > doing, then end the code with > > \peek_charcode:NT & { ... } { ... } > > to detect "&" and replace it by an active "&" (or rather by the > definition you have for it. I finally got around to test this. Simply adding \peek_charcode_remove:NT & { \sdaps_array_alignment: } seems to work perfectly! Thanks, Benjamin