Forced return, non-breaking hyphens & spaces, suppress hyphenation + XML

Question

Forced return (linefeed), non-breaking hyphens and spaces, suppress hyphenation.
None of these are preserved when exporting from FrameMaker to XML, since they do not seem to be represented by a Unicode code point. My question to you is: How do you deal with those things in XML?
The last issues (non-breaking and suppress hyphen) have recently been brought up in:
http://forums.adobe.com/thread/450363
http://forums.adobe.com/thread/459503
Forced return is a common thing in many FrameMaker documents to improve readability of certain phrases.
For export of FM to XML, there have been proposals to use a special element with a prefix just to capture the special FrameMaker symbol. It works, and may be a valid useful path in certain cases, but I think that it is a questionable way of dealing with it for several reasons:
It is only relevant for roundtrip, since these special elements will hardly be interpreted by other XML tools, which of course limits the value of XML export.
It is unwieldy, to say the least, to require the user to insert special elements for saying simple things that otherwise are just natural key strokes in the regular text flow, and which are not perceived as structural elements of information. Most users would think of these symbols/charactes as control characters, and there is no validation warning that says you may not use these characters/symbols.
An element is used for formatting purposes only, whereas all other elements are used for content or structure.
There is no automatic way of transforming an existing text that has these "symbols" into some special element when a document is structured with a conversion table.
There is no automatic way of transforming a structured FM document to XML such that these special "symbols" get translated to some suitable XML construct.
If the last point could be solved, i.e if all those control characters or markers could automatically be translated to a suitable XML representation, then I would consider the whole issue as solved, otherwise not.
Even without FrameMaker, how do people deal with these things in "pure xml". For instance, when XML is used for publishing (which I know Arnis Gubins is doing), there will guaranteed be a need to control both hyphenation and line breaks. So how do you (they) do that?
How do other vendors cope with these issues, e.g XPP?

Answer 1

Lynne,
As anyone can see, entity declarations have not really been in the domain of my expertise (understatement), but I might just learn bits and pieces...
Thanks! I have now done some more reading in various pdfs, such as scructapps etc, but also the w3c xml spec, all of which I have "read" before, but reading is not always the same as understanding...
I now have used the "entity approach" to make both discretionary hyphen and suppress hyphen work, so that it is represented in the XML export and round-trips just fine.
Forced return still puzzles me somewhat though: I have a working solution for that using the same entity approach, but it will not work for text ranges (although it is a bit odd to have forced returns in text range elements). Moreover, I am not certain that it really is the best way. In reading other posts on this issue, I have seen that some people want forced returns to really be linefeeds in the xml output, with no other linefeeds, and conversely, when importing xml that are "formatted" in lines, such as code, they want to preserve that.
One  way to achieve that is to use:
     reader line break is forced return;
     writer line break is 1000 characters;  (or more characters)
Then it is completely symmetric (i.e works also if some other app has generated the xml with intentional line breaks. And this method is global for all elements, and it works for me.
Another way to achieve this is to use the following, but it is only valid inside an element:
     preserve line breaks;
     writer line break is 1000 characters;
Then it is also completely symmetric (in the above sense), and it works for me.
The latter method has the drawback that it only works for text in the element; it is not inherited to its children.
But if we look at only one element, what is the difference between the two methods?
As far as I have been able to see, the results are identical! Why two methods? The first one seems more powerful and general(?)
Scrutinizing the documentation though, it says that 'preserve line breaks' will add an attribute 'xml:space', but I can't see that in my output?
Also, concerning the documentation for line break, it says that FM would ignore line breaks when exporting, but it does NOT do that (fortunately). Forced returns always result in linefeeds, no matter what.
I would be thankful if these issues could be explained, or elaborated.
Also, would you recommend against any of these methods?
With my preferred method of using the global 'reader line break is forced return' instead of a local (or many local) 'preserve line breaks', there is of course the danger that when importing xml, it is absolutely necessary that the xml really only has line breaks where they are intended, and not generated every 80 characters or so!
Is there anything that says it is "ugly" or "bad style" to honor line breaks, and generate long lines?
Finally, why do we need to limit the number of characters written in one line these days? Why 80, why 1000, why not an unlimited number of characters!?
Will software these days really crash if given a very long line (assuming that it doesn't exceed total ram memory of course)?
Sorry about so many questions, but I can't find any answers to them in the docs I have read and searched.