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Re: Processing external data entities

From: James Clark <>
Date: Thu, 27 Mar 1997 17:55:09 +0700
At 20:37 26/03/97 -0500, David Megginson wrote:

>I had assumed that I would use something like this:
>  (element LISTING
>    (let ((ename (attribute-string "SOURCE"))
>          (nname (entity-notation ename)))

You need let* there.

>      (make external-graphic
>        entity-system-id: (entity-system-id ename)

You should use entity-generated-system-id so it works when your entity is
declared with a public id.

>        notation-system-id: (notation-system-id nname))))

Similarily you should use notation-generated-system-id.

>It would require only minor modifications to the Jade RTF backend to
>support special handling for a source-code-listing notation.  Is this
>a legitimate use of the 'external-graphic' flow-object class?  If not,
>we could implement some extensions to the expression language for
>read-only file input, since they would be side-effect free.

It would be simple and easy to have an external-procedure that returned as a
string the contents of an entity with a given system identifier.  This is
something that probably ought to be added to DSSSL at some point.

As regards your earlier question, there's no way without the query option to
handle references to external data entities occurring directly in content.