SAX: Comments (question 7 of 10)

David Megginson (ak117@freenet.carleton.ca)
Sat, 3 Jan 1998 13:21:01 -0500


[SAX is a proposal for a simple, event-based XML API, using
callbacks. This is one in a series of ten design questions that we
need to answer to implement the API.]

Should SAX include an event for comments?

public void comment (char ch[], int length);

CON

---

- comments are purely lexical, and do not form an integral part of a document's information set for processing (as opposed to authoring or archiving);

- including comments in SAX might encourage comment abuses like those common in HTML (i.e. enclosing 800 lines of JavaScript in a comment).

PRO

---

- the DOM includes comments in the core level-one implementation;

- HyTime uses comments for lexical constraints.

MY RECOMMENDATION -----------------

No.

SAX is not designed for authoring tools or repositories, that need to preserve the lexical as well as the logical structure of a document, and there is no compelling reason to report comments here except for DOM building (and we can always leave them out of a DOM).

The conventional comments in HyTime are not required, and personally, I believe that they should not have been there in the first place.

FURTHER CONSIDERATIONS ----------------------

Another lexical feature that I am not discussing here is CDATA sections; I assume that, when the parser is reporting character data, it does not matter how the parser obtained those characters (in a CDATA section, or in regular #PCDATA with the delimiters escaped using references). I am happy, of course, to listen to other opinions on this subject.

All the best,

David

-- 
David Megginson                 ak117@freenet.carleton.ca
Microstar Software Ltd.         dmeggins@microstar.com
      http://home.sprynet.com/sprynet/dmeggins/

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