Whitespace

[Tim Bray]

At 05:11 PM 26/08/97 GMT, Peter Murray-Rust wrote:
>	2. that it is always *possible* to create an XML document in which no 
>		non-significant whitespace appears.
>	3. the XML-WG, in its wisdom, has found it useful to allow authors
>		to pass the attribute XML-SPACE="DEFAULT" to the application.
>
>I believe that (2) is David's position which is logical and consistent. If
>(2) is universally applied then I can see no value in (3). It suggests that
>there is value in passing non-significant whitespace to the application and
>processing it in some application-dependent way. If we are processing 
>whitespace by stylesheet, then isn't DEFAULT 
>irrelevant? My problem is probably mainly because, after *much* debate, (3) 
>has been included in the spec and I don't see what it is for.

Well DEFAULT is 'irrelevant' in that it expresses no opinion about what
should be done with whitespace.  the PRESERVE value exists to support
constructs like HTML's <PRE>.  Yes, putting XML-SPACE="PRESERVE" on
something with element content is at the least questionable; but the
fact that this can be used to do something stupid does not mean it
isn't useful.

>At present we have (at least) the viewpoints:
>	- whitespace matters and authors must define precisely what they want
>		in a document. The SGML community can understand and manage
>		whitespace. If newcomers find it difficult, they'll have to
>		learn the rules, or use proper tools.

Well, they only have to learn one rule: the whitespace you put in
the document is the whitespace that is in the document.  XML neither
addeth nor taketh away.

>	- most of the people who will want to use XML will graduate from HTML.
>		This has 'taught' them that whitespace is not significant and
>		gets normalised somewhere. They will start creating XML by 
>		analogy with HTML. XML will not succeed unless we can
>		offer some support for this transitional period.

Uh, if they are using it for browser applications, I am quite sure that
browsers, while doing XML, will duplicate the HTML whitespace semantics,
i.e. eat most of it, and people will just not notice the difference.
Another way to say this is that the "HTML" whitespace semantic should
probably be renamed the "browser" whitespace semantic.

It would be a good and useful thing to write down (precisely) what
that browser semantic is; it's a little subtler than you'd think.

When they get into more ambitious apps than just browsing, they will
be glad of XML's transparency.
 - T.

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