Re: TeX in \xmlsetentity and DTDs in DOCTYPEs

[Hans Hagen <pragma@wxs.nl>]

On 1/18/2016 9:49 PM, Kate F wrote:
> On 18 January 2016 at 19:13, Hans Hagen <pragma@wxs.nl> wrote:
>> On 1/18/2016 5:22 PM, Kate F wrote:
>>>
>>> On 18 January 2016 at 13:30, Thomas A. Schmitz
>>> <thomas.schmitz@uni-bonn.de> wrote:
>>>>
>>>> On 01/17/2016 07:24 PM, Hans Hagen wrote:
>>>>>
>>>>>
>>>>> it should work in the in beta now
>>>>
>>>>
>>>>
>>>> Hi Hans,
>>>>
>>>> now I have a problem :-) What should take precedence if an entity is both
>>>> defined in the dtd and as a \xmltexentity? The way I see it, the latter:
>>>> e.g., in the DTD, I might declare something for use in a browser but
>>>> require
>>>> a different solution when typesetting with ConTeXt. The latest and
>>>> greatest
>>>> now takes my DTD definitions instead of the \xmltexentities, which did
>>>> not
>>>> happen before. Is that an unwanted side effect or the new default?
>>>>
>>>
>>> Ah, there's a bug:
>>>
>>>       <!ENTITY i.opt "<option>-i</option>">
>>>
>>> This should produce an <option> node in the DOM tree, just as if you'd
>>> typed that out where the entity is used. Currently ConTeXt takes that
>>> as literal text, as if you'd typed "&lt;option&gt;-i&lt;option/&gt;"
>>>
>>> Often I wish XML weren't so complex...
>>
>>
>> are you sure? i've never seen that
>>
>> Hans
>
> Yep!
>
> These are called "internal parsed entities". "Parsed" requires that
> any tags *inside* the entity must be balanced, unlike in SGML
> entities.
>
> Sorry I can't find a clear explanation in the XML spec; it's a pretty
> confusing document.
> But here's some random person's slide illustrating an example:
> http://images.slideplayer.com/23/6622270/slides/slide_47.jpg
>
> libxml2 deals with these correctly, which is what I've been using
> (xsltproc and friends) for my documents which use them. I generally
> trust libxml2 to get things right.
>
> I use these entities to centralise often-repeated fragments between
> documents, kind of like how you might use a primitive macro in TeX.
>
> So for example in one external DTD I have some general things:
>
>      <!ENTITY macro.arg  "<replaceable>macro</replaceable>">
>      <!ENTITY equal.lit      "<literal>=</literal>">
>
> And then in one specific document's internal entities, something which
> uses them:
>
>          <!ENTITY D2.opt
> "<option>-D</option>&macro.arg;&equal.lit;<replaceable>defn</replaceable>">
>
> Then if I change my mind about how I want to mark up "=", for example,
> I only have one place to change it. This makes life with XML a little
> bit less painful.

well, i've learned not to trust all these docs on the web too much and 
applications can do what they want (and thereby even influence standards)

xml pocket reference:

- parsed entity: replacement text that can be referenced

   internal: literal string to be injected (then the example
             shows only text and entities

in your example you use a (decimal) character entity ... the link you 
give says that you cannot use & and % as part of the entities value so 
that would mean your example is wrong

of course we can consider an option to parse the entity as xml

(we can consider < as a trigger for parsing thereby kin dof 
automatically adapting)


Hans

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