# Look up an attribute's XML 1.0 qualified name by index.
#
# Parameters:
#
# * `index`: attribute index.
#
# Returns:
#
# The XML 1.0 qualified name, or the empty string
# if none is available, or `null` if the index
# is out of range.
#
# SEE: `length`
fun qname(index: Int): nullable String is abstract
lib/sax/attributes.nit:83,2--96,51