🚀 go-pugleaf

In <1802@igd.fhg.de> Hans Holger Rath writes:
>Is the first element definition equivalent to
>
>   <!ELEMENT x - - (z, ((a* | b)*)) > ???

I'm assuming you meant:
    <!ELEMENT x - - (z, ((a* | b*))) > ???

>                        _      _
>
>I don't think so and Mr. Martin Bryan in "SGML an Author's Guide", page 111 don't
>think so, too.
>
>I always thought, that the occurence indicators ("?", "+", "*") have a higher
>precedence than the group connectors ("|", ",", "&").
>
>What do the experts think about these problems?
>
>Thanks in advance,
>
 --Holger

I tried the test case with two different parsers (IBM SGML Translator
release 2 and release 3) and both flagged the B element as out of
context, which they should have.  Even if the grouping operator did
take precedence in (A* | B*), B is still invalid because the OR group
itself is not repeating and thus only A or B can be specified
(regardless of the repitition operators).  Thus, if A is specified, B
cannot be specified.  This suggests that (A* | B*) is equivalent to
((A*) | (B*)), which they are.  Both say "A repeated OR B repeated".
The grouping around the individual tokens does not change the meaning.

Eliot Kimber                      Internet:  drmacro@ralvm13.vnet.ibm.com
Dept E14/B500                     IBMMAIL:   USIB2DK9@IBMMAIL
Network Programs Information Development     Phone: 1-919-543-7091
IBM Corporation
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