Is XML something like “monastic SGML”?
Yes, XML bears a strong resemblance to the kind of restricted SGML that a lot of organizations already produce as a matter of policy. The most noticeable feature of XML documents is that all of the end-tags are present and they all contain the GI of the element that they close. Since many organizations require production SGML documents to conform to this rule anyway, a lot of existing SGML documents are very close to being XML documents just the way they stand. Q: That doesn’t sound like much of a difference. What’s the big deal? A: Well, let’s put it this way. The standard SGML reference is almost 500 pages long, plus about another 100 pages of annexes. The current XML specification is 26 pages, not counting the list of contributors. Q: Wow! There must be a lot of stuff missing. What got taken out? A: Basically, all the SGML features that make SGML client software difficult to implement. The most obvious of these hard-to-implement features are the ones that were put into the standard
