Re: [xml] Parameter entities ?

[Bruce Miller <bruce miller nist gov>]

Raphael Hertzog wrote:
> Hello,
>
> does libxml fully support parameter entities ? It doesn't looks like so ...
> is there any explanation ?
>
> By parameter entity I mean things like that :
>
> <?xml version="1.0" encoding="ISO-8859-1" ?>
> <!DOCTYPE vide SYSTEM "test.dtd" [
> <!ENTITY % debian "INCLUDE">
> <!ENTITY % caldera "IGNORE">
> <!ENTITY % redhat "IGNORE">
> ]>
> <vide>
> <![%debian[ Debian blabla ]]>
> <![%caldera[ Caldera blabla ]]>
> <![%redhat[ Redhat blabla ]]>
> </vide>
>
> This file when run through xmllint complains about the <![...]]> because
> it's not a valid element. :)

Parameter entities are fully supported, as far as I can tell.

But conditional section can only appear in a dtd.  They need to be
in the internal subset up before the ]>
OTOH, since you're wanting it to expand into text, not a declaration,
you'll probably need the intermediate step of defining a general
entity in one of 3 ways according to which of the 3 systems 
you're discussing.  Ie.
<![%debian[ <!ENTITY blablah "Debian blabla">]]>
etc.

Whoa, I was just rechecking the spec, and xml 1.0, at least, seems
to say that conditional sections can only appear in the external
subset, not in the internal set.  

> Ultimately I'd even need to be able to force by command line (to xsltproc
> or xmllint) one of those entities to INCLUDE in order to do a kind of
> conditionnal processing... (and by default all those entities would be
> set to IGNORE).

Hmm, not so sure you can do that with straight xml (& xmllint), but you
can pass parameters to xsltproc.  Probably a better approach would be to
put all three chunks of stuff in your doc 
<stuff>
  <debian-stuff>Debian blahblah</debian-stuff>
  <caldera-stuff>  ...
</stuff>
and use xslt to extract the right subset according to an xsl parameter?

----------------
Bruce Miller
<bruce miller nist gov>  http://math.nist.gov/~BMiller/