Am 07.06.2012 03:20, schrieb Donald Arseneau: >>>> The approach that we have taken for this is to use "@@" as the indicator >>>> for internal code: > > Too bad "@@" is currently the indicator for a renamed TeX primitive. yes they are, but we thought this nevertheless acceptable in an L3 context. While expl3 runs on top of 2e there is a slight chance that you may want to refer to 2e commands in expl3 code and within the 2e commands to the handful of @@ frozen primitives. However, those either exist as expl3 names, eg \tex_par:D instead of \@@par, or we could provide them (or you have to not use the @@ convention in that part where you really need them). at least that was our conclusion so far. frank