[#expr]expression[/#expr]
where:
The expr tag can be inserted as a child of the following tags: file and picture. What is done with the evaluated expression depends on the parent tag; consult the respective documentation for more details.
expr tag in a file:
[#paramaters]package : uml21.Package[/#parameters]
[#file]Documentation_[#expr]package.name[/#expr].xml[/#file]
...