You should have mentioned you are using HTML::Template. Otherwise, only those who recognise the variable style can answer.

Your question is fairly common on the HTML::Template mailing list, and IIRC, the answer is "you can't do that - at least not that way".

I see two solutions to you problem:

• You can define a HTML::Template filter. That filter can then look for the TMPL_INCLUDE tag and insert the correct filename.
• You can have a series of <TMPL_IF><TMPL_ELSE> statements which enclose each TMPL_INCLUDE statement you might want to execute - and the TML_IFs then determine what gets included in the usual fashion.
• You could have a single include file, and then use the TMPL_IFs inside that include file to select which contents of that file you want.

Each of these solutions has good points and bad points. The first is most general, the last is probably quickest.