Hello all, Consider the following: \documentclass{article} \usepackage{expl3} \begin{document} \CodeStart \def\temp{a~b~c} \err_info:nn{\temp~stuff}{} \err_info:nn{\temp\ stuff}{} \err_info:nn{\temp\~stuff}{} \err_info:nn{\temp\c_space_token stuff}{} \err_info:nn{\temp\space stuff}{} \CodeStop \end{document} Only the last one works as intended (by me). Is there a LaTeX3 way to do this? -- Joseph Wright