I thought (naively) that writing \tl_set:Nx \l_tmpa_tl { \tl_to_uppercase:n {text} } would put TEXT in the variable \l_tmpa_tl (as revealed by \tl_show:N \l_tmpa_tl). It doesn't, and nothing else that I've tried does either. What is the recipe for getting \l_tmpa_tl to contain TEXT, starting from text? Andrew