Whenever I have needed to do an output like that of an arbitary depth I found a recursive function to be the easiest way to acomplish it.
You put your <cfoutput....> logic into a <cffunction...> tag. Pass in the query and start looping over the top loop. Then inside that loop test to see if that node has child nodes, if so call the same function to output that level.
I don't really have a code sample I can lay my fingers on at the moment, but if this question is still open in a few hours I may have time to cook something up.
HTH
Ian
Firstly to Ian: the whole idea behind using nested sets for hierarchies is so that one doesn't need to use recursion. So falling back on recursion - whilst it'll work - kind of defeats the purpose of using nested sets.
Now, to the problem.
I think the OP is pretty much there, except for the handling of when to open and when to close the <ul/> blocks.
I am presuming you have got your DEPTH values correct for this. If not, we can come back to that.
As you scan down your recordset (ordered by LEFT), if the DEPTH increases (from the previous record), you need to start a new UL, so instead of just rendering a <li/> (where that's the whole <li>label here, etc</li>), you need to rendered a <li><ul><li/>. If the depth stays the same: just a <li/>. If the depth decreases, you need to close as many <ul> tags as there is difference between the current and previous depth (because you could be at the end of more than one "generations", eg: it could be the youngest child of this generation of the youngest child of the preceding generation). So that's </ul></li> for each level.
I think using <ul> for this sort of thing is correct, but one could also use <div> tags, and this is easier.
The query to generate the correct nesting is along these lines:
select left as nodeOrder, 'OPEN' as nodeType, label, [other columns as necessary]
from tbl_set
union
select right as nodeOrder, 'CLOSE' as nodeType, '' as label, [blanks for other columns]
from tbl_set
order by nodeOrder
(you'll probably need a WHERE statement to suit your requirements here too).
This gets the opening and closing nodes in the right order, as well as the correct number of closing nodes in the right sequence. This is great for generating XML, and I suppose from there one could even use an XSLT to convert that to a <ul/> hierarchy.
But at the very least, one can now simply loop over that record set and output a <div> for each OPEN and a </div> for each CLOSE, and you'll end up with a well-marked-up hierarchy. It's just a matter of doing the CSS to display it nicely from there.
Again, <ul> tags are the better sort of mark-up here, semantically.
HTH.
--
Adam
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