One difference between SGML and XML which does make a substantial
difference for text annotation purposes, however, is the loss of
concurrent markup. For instance, in SGML, it would be possible to
annotate a hierarchical physical structure of book/signature/page as
well as a logical structure of chapter/section/paragraph. Clearly,
the physical and logical structures only coincide in some respects.
For instance, chapters will often start on page boundaries, but
paragraphs cannot do this. There are workarounds, but XML basically
cannot do this task without some serious cleverness or loss of
utility.
>>>>> "lb" == Lou Burnard <lou.burnard@computing-services.oxford.ac.uk> writes:
lb> The differences between annoation using SGML and annotation
lb> using XML are fairly trivial, mostly relating to the "surface
lb> form" of the annotation.