\startbuffer[test]

<what>

<emptynode value="!empty node!"/>

<notemptynode>!not empty node!</notemptynode>

</what>

\stopbuffer

\startxmlsetups xml:mysetups

   \xmlsetsetup{\xmldocument}{something|emptynode|notemptynode}{xml:*}

\stopxmlsetups

\xmlregistersetup{xml:mysetups}

\startxmlsetups xml:emptynode

node=\xmltag{#1}:\crlf

ifxmlselfempty-else-fi:\space

\ifxmlselfempty{#1}

attribute = \xmlatt{#1}{value}

\else

content = \xmlflush{#1}

\fi

\crlf

ifxmlselfempty-else-fi reversed:\space

\ifxmlselfempty{#1}

content = \xmlflush{#1}

\else

attribute = \xmlatt{#1}{value}

\fi

\blank

\stopxmlsetups

\startxmlsetups xml:notemptynode

node=\xmltag{#1}:\crlf

ifxmlselfempty-else-fi:\space

\ifxmlselfempty{#1}

attribute = \xmlatt{#1}{value}

\else

content = \xmlflush{#1}

\fi

\crlf

ifxmlselfempty-else-fi reversed:\space

\ifxmlselfempty{#1}

content = \xmlflush{#1}

\else

attribute = \xmlatt{#1}{value}

\fi

\blank

\stopxmlsetups

\startxmlsetups xml:something

\xmlall{#1}{./emptynode}\blank

\xmlall{#1}{./notemptynode}\blank

\stopxmlsetups

\starttext

\ConTeXt\ \contextversion\blank

   \xmlprocessbuffer{main}{test}{}

\stoptext