Hi, the conditional for ##3 is wrong (should be true). \unexpanded\def\processassignlist#1[#2]#3%   {\def\syst_helpers_process_assign_list_assign[##1=##2=##3]% -    {\doifnot{##3}\relax{#3{##1}}}% +    {\doif{##3}\relax{#3{##1}}}%    \def\syst_helpers_process_assign_list_step##1%      {\syst_helpers_process_assign_list_assign[##1==\relax]}%    \processcommalist[#2]\syst_helpers_process_assign_list_step} Wolfgang