Re: external entities

ext is an internal entity that happens to be defined in an external 
subset.  This is, in fact, the typical case for internal entity 
definitions since internal subsets are relatively rare in the wild. 
   (See, for example, the DocBook DTD, which provides a 
"dbgenent.mod" external entity as a placeholder precisely for 
containing internal entities: 
http://www.oasis-open.org/docbook/xml/5.0a1/)  Just because your 
internal entity is called "ext" doesn't make it external in any way.

Hope this helps,

	Eve

Junfeng Dong wrote:
> Dear Sir or Madam,
> 
>  
> 
> I have a question for the definition of external entities. Suppose there 
> is an xml document given as follow:
> 
>  
> 
> <!DOCTYPE root SYSTEM "ext.dtd" [
> 
> ]>
> 
> <root a="&ext;"/>
> 
>  
> 
>  
> 
> The content of file ext.dtd is:
> 
>  
> 
> <!ELEMENT root ANY>
> 
> <!ATTLIST root a NMTOKEN #IMPLIED>
> 
> <!ENTITY ext "blah">
> 
>  
> 
> Is entity ext counted as an internal entity or an external entity? In 
> xml specification, “The document type declaration can point to an 
> external subset (a special kind of external entity 
> <http://www.xml.com/axml/target.html#dt-extent#dt-extent>) containing 
> markup declarations,” In my understanding, since ext.dtd is an external 
> subset and a special kind of external entity, then ext is by default, an 
> external entity. However, by the definition of internal entity (“If the 
> entity definition is an |EntityValue 
> <http://www.xml.com/axml/target.html#NT-EntityValue#NT-EntityValue>|, 
> the defined entity is called an *internal entity*. There is no separate 
> physical storage object, and the content of the entity is given in the 
> declaration.”), entity ext is an internal entity.
> 
>  
> 
> I am confused here. Since if ext is an external entity, then the 
> document isn’t well-formed.
> 
>  
> 
> Thanks in advance.
> 
>  
> 
> Junfeng
> 

-- 
Eve Maler                                         +1 425 947 4522
Technology Director                           eve.maler @ sun.com
CTO Business Alliances group                Sun Microsystems, Inc.

Received on Thursday, 7 July 2005 14:04:04 UTC