🚀 go-pugleaf

  Never let it be said that I didn't give a man an honest chance to win 
back his beer.  Besides, I am curious to see exactly what you will settle 
for, once I make the problem a bit more ugly. So let me remove the 
requirement that your result be constrained by the content model, and just
require that the markup somehow be reasonable, where you get to define what
"reasonable" means.  You don't even have to do this in SGML. 

  Once again, consider the markup of a stream with overlapping elements
(three elements this time).

  Here is the text:

	now is the time for all good

  And the contents of each element (and of their overlaps) is defined as 
follows (where the operator "^" means intersection):

  X:	now is the for
  Y: 	is the for all
  Z: 	the for all good
  X^Y:	is for
  X^Z:	the for
  Y^Z:	for all
  X^Y^Z: for

  Note that the elements are not contiguous subsequences of text.  If 
you draw a Venn diagram with three overlapping circles and put the words 
in the various regions as the element membership requires, it might be 
easier to visualize.  Never mind that it seems bizarre.

  Now, the markup problem I pose is the following: insert tags in the 
text, corresponding to X, Y, and Z, that demarcate the various regions
in such a way that a "reasonable" person or program can identify all
the elements and overlaps, and would not infer non-existent relationships.

-Darrell.