xml-dev - Re: Quotes in PEReferences

[Chris Hubick <maillist@chris.hubick.com>]

On Thu, 6 Aug 1998, Chris Hubick wrote:

> <!DOCTYPE test [
> <!ELEMENT test (#PCDATA)>
> <!ENTITY % p0 "a quote (&#34;) test">
> <!ENTITY % p1 "<!ENTITY e1 &#34;">
> %p1;%p0;">
> ]>
> <test>This is&e1; .</test>
> 
> My first thought for expanding PEReferences at the lexical level was to
> just convert any quotes in the replacement text to &#37;, but that would
> break the above example.  How does one tell to escape the quote when
> substituting p0, but not when substituting p1?  Ahhh!

	Well, I figured out a way to solve this problem in my parser, when
asking the lexical level for a character, the object in the grammar/parser
layer can just pass down a this pointer which will give the lexical layer
access to the current production hierarchy up to the point where
the character is being requested.  That will let me know if I am in a
Comment, EntityValue, DocTypeDecl, or whatever, and allow me to take the
appropriate action.  I think. :-)

> 4. It shall be easy to write programs which process XML documents. 

	Did somebody say easy? :-)  Compared to what?  Ok, so it isn't
_that_ hard, but I don't know if I would call this easy in the trivial
sense of the word.  PE References definitely take this beyond quick
weekend hack.

---
Chris Hubick
mailto:chris@hubick.com
http://www.hubick.com/



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