Reply to: Validation Error with conrefApril 3, 2013 at 6:41 pm
I see where you're coming from, but DITA conref is not like XML entities (the closest thing I can think of to what you are suggesting).
DITA conref is more along the lines of XInclude (if you must equate it to something, though they differ in some respects).
According to the XML recommendation (W3C) an entity is expanded before validation occurs and that might allow you to do the type of thing you are thinking of. This can be done because entities are part of the XML recommendation and so this special step (expand the entity before validating) is performed by validating XML processors.
DITA, as an application of XML, basically sits on top of the XML rules and cannot override those rules or inject new ones, instead it must work within those existing XML validation rules. That means each XML document must be valid unto itself and you cannot rely on a validating XML processor to break those rules and make an exception for specific document types or other specifications. First and foremost XMetaL Author Enterprise is an XML authoring tool and so it obeys the XML rules for validation, which is not to say that DITA breaks those rules. DITA is designed to work within them.