Preceding Sibling

mphare · March 3rd, 2009, 03:40 PM

I'm using Saxon 9

I'm parsing a table structure. On a particular row, I may decide I need to look at information on the preceding row.

So, I have a template that processes the table by rows.

I set a var $row to the current row and read a value like $row//Name

if the value of Name is of particular interest, like empty, I look for it on the preceding row

I'm trying $row/preceding-sibling//Name and I'm not getting a value.
Am I using this expression correctly?

[EDIT]

No, I'm not.. I needed $row/preceding-sibling::row[1]//Name and it works just fine.

Thanks,

- m

joefawcett · March 3rd, 2009, 10:12 PM

No, preceding-sibling is an axis so you must specify the element (in this case) as well. I can't believe you didn't get an error rather than just no output:

Code:

$row/preceding-sibling::row//Name

or:

Code:

$row/preceding-sibling::row[1]//Name

if you want the first preceding-sibling.
But not sure why you need //Name rather than /Name, what is the structure of the XML?

mphare · March 4th, 2009, 10:32 AM

I need //Name because Name is not a direct child of row. There is a cell element inbetween. I guess I could have gone with /cell/Name, but it didn't seem necessary.

I was not getting an error because I had originally mispelled preceding-sibling as preceeding-sibling, so the parser didn't know it was supposed to be an axis. Once I added the ::row, the parser immediatly errored telling me preceeding-sibling was not a valid axis. Once I fixed that, everything else fell into place. This is when I added the [EDIT] to the original post.

Thanks for the help.

joefawcett · March 4th, 2009, 11:04 AM

That makes sense. Normally it is better to use the full path rather than // as the latter is an expensive operation.