"
>enumerate</I
> tag
is one starting with the string "[]" followed by a
comma-separated list of element names, followed by a sub-expression enclosed
in curly braces.  The list of values for the named elements are walked in
parallel and the sub-expression expanded each time with a pattern just having
a single value for those elements, starting from the first value and
continuing as long as any of those elements has a value.
For example, the format "%{[]family,familylang{%{family} (%{familylang})\n}}"
will e