[ZPT] forcing a string to be a path

[Adam]

I am attempting to include different content based on a variable in the
url, fish?content=trout.  In my template doing something like:

<span tal:replace="structure request/content">content goes here</span>

ends up replacing the tag with the string "trout" instead of the
contents of the file named trout.  I thought I could work around this by
forcing it to be interpreted as a path using path:request/content, but
that didn't actually change anything.  Is there a way to include a file
based on a variable like this?

Thanks
Adam