Another (sort of) related question. I'm try to add something to an existing delimited macro. Given an initial macro: \def:Npn \my-macro #1\q_stop {Stuff~here} I can do: \toks_set:Nn \l_tmpa_toks \exp_after:NN \exp_after:NN \exp_after:NN {\cs:w my-macro \cs_end: ##1 \q_stop} \def:cpn {my-macro} #1\q_stop {\toks_use:N\l_tmpa_toks Added~stuff} to add things on. However, I again wonder if I'm missing a better way (I tried things with \exp_not:Nf and so on, but failed). -- Joseph Wright