On 05/02/2012 18:01, Bruno Le Floch wrote: > \regex_const:Nn \recurrence_tl_integer_regex { ^[-+]*[0-9]+$ } > % => \l_recurrence_integer_regex > \regex_const:Nn \recurrence_tl_true { true } > % => \l_recurrence_true_regex Constants => \c_... -- Joseph Wright