Hi all! As I was learning LaTeX3, I stumbled upon some information missing from the docs. Apparently the \cs_new: functions (and friends) do not handle expansion for you just because you use 'x' in your argument specifier. They should be used only to define the base function and variants should be defined with \cs_generate_variant:Nn. I feel like this should be part of the docs, since it's a pretty basic rule. I've attached a small patch. Tell me what you think. Cheers! -- www.mhelvens.net