URI templates and "back references" - a question

Hi,

I have written some simple C code to process and match URI templates
against URIs. I'm using the "va_list" approach to create a C function
that takes a URI template (as a string) and a variable-length list of
string values to put into the template, creating a URI with all
substitutions made.

I can't tell from the specification whether this is a good idea ;)

But, for this usage, I don't really need named variables. I could
certainly choose to use distinct variable names anyway, and essentially
discard them during the substitution, but my usage seems a little
similar to the idea of backreferences in regular expressions, and I was
wondering whether it makes any sense to standardize a variable name for
when the name is not important, or for a specific ordering of values?

Cheers,

- John