Re: Occurrence indicators for #PCDATA

Paul Prescod (papresco@technologist.com)
Sat, 26 Jul 1997 12:38:00 -0400


Message-ID: <33DA27E8.E7C864B0@technologist.com>
Date: Sat, 26 Jul 1997 12:38:00 -0400
From: Paul Prescod <papresco@technologist.com>
To: Holger Wahlen <wahlen@ph-cip.uni-koeln.de>
CC: www-html@w3.org
Subject: Re: Occurrence indicators for #PCDATA

Holger Wahlen wrote:
> 
> Is there any difference between
>         (#PCDATA),
>         (#PCDATA)?,
>         (#PCDATA)+
> and     (#PCDATA)*
> in an element content? 

I think you mean "in content models". Element content means something
else. 

Difference: not really. But there is a big difference in these content
models:

         (#PCDATA|A),
         (#PCDATA|A)?,
         (#PCDATA|A)+
 and     (#PCDATA|A)*

Since content models of (#PCDATA) are often extended to (#PCDATA|FOO)*
it might be a good habit to just put in the * after (#PCDATA) so that
you don't forget later. Or else if you contract a content model from
(#PCDATA|FOO)* you might not bother to remove the * at the end. That
might explain the inconsistent practice in the HTML spec.

 Paul Prescod