In order to differentiate between the case of an absent or an empty attribute on an xml-element I now use the following macro to set a TeX- \if: % #1=node #2=attribute #3 defaultvalue: execute \attributetrue/false \def\setFlagToAttribute#1#2#3{% \doifnot{\xmlattdef{#1}{#2}{NOTPRESENT}}{NOTPRESENT}% {\doifelse{\xmlatt{#1}{#2}}{\empty}% {\xmlvalue{choice}{#3}{\iftrue}}% {\xmlvalue{choice}{\xmlatt{#1}{#2}}{\iftrue}}% \csname#2true\endcsname\else\csname#2false\endcsname\fi }% } I find the use of the NOTPRESENT not very elegant. Is there a path expression and function that can tell the presence or absence of an attribute, just as its value can be filtered with a/b[@option==value]? Hans van der Meer