[NTG-context] presence of xml-attribute

8 Jun 2010

      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

[NTG-context] presence of xml-attribute

H. van der Meer