ExternalEntityRef(p, subparser, base$, sysid$, pubid$)
subparser
parameter contains a parser handle created with the same callbacks and
context as the main parser and should be used to parse the external entity.
The base$
parameter is the base to use for relative system identifiers. It is set
by parser:SetBase() and may be Nil
. The sysid$
parameter is the
system identifier specified in the entity declaration and is never Nil
.
The pubid$
parameter is the public ID given in the entity declaration and may be
Nil
.