Message-Id: <9603191923.AA17113@www10.w3.org> Date: Tue, 19 Mar 96 11:23:06 CST From: "C. M. Sperberg-McQueen" <firstname.lastname@example.org> Subject: <insert> and external entity references To: email@example.com Excuse me if someone explained this while I was not paying attention, but why are we talking about adding an INSERT tag with the semantics 'go find this file or document, and insert it here', when SGML already has the mechanisms needed for this, in the form of entity references? Why not just start writing, requesting, or demanding HTTP servers that actually understand and process references to external entities as defined by ISO 8879? To illustrate, for those not yet conversant with all of SGML: for this ... > Now, my serious question is, at this time could one simply use > > <insert > data="http://www.mysite.com/path/file.html" > > > </insert> a normal SGML syntax would be this: 1 in the document type definition, <!DOCTYPE html PUBLIC "-//IETF//DTD HTML 2.0//EN" [ <!ENTITY myfile SYSTEM "http://www.mysite.com/path/file.html" > ]> 2 in the text itself, &myfile; As has been pointed out, this depends on having an SGML parser which supports URLs as system identifiers. For local documents, it is equally easy to use a normal file id: <!ENTITY myfile SYSTEM "/usr/me/public_html/file.html"> If it is desired (as some have proposed) that the external entity be parsed as a completely independent object, the required variation in the syntax is again already provided by SGML: just declare the external entity as a SUBDOC (i.e. a free-standing document, to be parsed on its own, not as part of the current document). <!ENTITY myfile SYSTEM "/usr/me/public_html/file.html" SUBDOC> N.B. not all SGML software supports the SUBDOC feature, just as not all SGML software understands URLs, which are not after all defined by ISO. That shouldn't make too much difference, I think: we are talking about a change to HTTP and/or HTML, and that means rewriting at least some software. Is there an advantage to inventing a new notation for inclusion of documents and document fragments, rather than using the existing notation? Or is it just not widely known that notation for such inclusion already exists and need only be adopted, instead of being invented? -C. M. Sperberg-McQueen Computer Center, Database Group University of Illinois at Chicago All opinions expressed in this note (except those I have quoted with a view to refuting them) are mine. They are not necessarily those of the University of Illinois, its administration or Board of Regents, nor of the Text Encoding Initiative, its executive committee or other participants, its sponsors, or its funders. Anyone who says otherwise is wrong.