[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: SAX and ignorableWhitespace

• To: xml-dev@l...
• Subject: Re: SAX and ignorableWhitespace
• From: Richard Tobin <richard@c...>
• Date: Tue, 6 Jan 2004 18:06:30 GMT
• Cc:
• In-reply-to: <024a01c3d40d$c0cb2cf0$6403a8c0@ARIMATHEA>
• Organization: HCRC, University of Edinburgh

>> The word "ignorable" is an
>> unfortunate choice here. It means the application receiving the data
>> may choose to ignore it. However, the parser cannot ignore this
>> content. It must provide it.

>I am willing to take that on faith, but just for the sake of throroughness,
>my question is more "why must it provide it". It seems that the same
>argument could be made for element and attribute declarations. Clearly the
>parser cannot ignore them, yet it is not required that the information be
>passed in one of the default interfaces-- they are only reported through the
>DeclHandler, an extension interface.

We must be quite clear here: it is the whitespace characters that
*must* be provided, not the fact that they are ignorable.  Only
validating parsers have to report that.

A non-validating parser is free to return ignorable whitespace using the
characters() callback instead, even in the presence of a DTD.

But a validating parser must report the fact that it's ignorable, and
SAX chose to report ignorableness by using a different callback.  If
that callback wasn't part of ContentHandler, you would have the
slightly strange situation that which interface reported the
characters would be different depending on whether you used a
validating parser.

>IIRC, the SAX interface set predates the Infoset spec, so any mandate to
>provide specific information to the application must have come from
>somewhere else.

As you observe, it's the XML spec that requires this.  The Infoset does
not place any requirements on what must be reported, just a terminology
for how to describe it.

-- Richard

• References:
  • Re: SAX and ignorableWhitespace
    • From: "Jeff Rafter" <lists@j...>

• Prev by Date: Re: Re: Cookies at XML Europe 2004 -- Call for Particip ation
• Next by Date: Re: Re: Cookies at XML Europe 2004 -- Call for Particip ation
• Previous by thread: Re: SAX and ignorableWhitespace
• Next by thread: Re: Formalism and complexity
• Index(es):
  • Date
  • Thread