# Note that the first argument of \def must not uses braces, and the second
# must use braces.
#
+# syntax: Either
+# \def\macroname{definition}
+# or
+# \def\macroname{definition} requires
+# or
+# \def\macroname{definition} extra xmlname requires
+#
+# ("" for empty strings is not supported. One would have to use x for fields
+# that are not set.)
+#
# If you put any symbol with a requirement inside an iffont clause, you
# must put an alternative definition with the same requirement in the
# corresponding else clause. Otherwise the LaTeX output would depend on the