# Re: Conditionally displaying a horizontal line

From: David Carlisle <davidc@nag.co.uk>
Date: Wed, 18 Sep 2002 17:35:11 +0100
Message-Id: <200209181635.RAA27471@penguin.nag.co.uk>

> - What is the purpose of the marker containing a line, which appears at the
> top of the flow and as the third item in the marker-line-marker combination?

That's the line that actually apears in the header.

> - If there is a horizontal line anywhere on page 2 (not necessarily at the
> top), then won't the first marker on the page always be empty regardless
> (meaning the line in the header never appears)?

The first marker on the page would be but what you want is the marker
"in scope" at the top of the page, which is \topmark in TeX  (where I
grew up:-) and in XSL is called...(checks spec)
first-including-carryover

to retrieve the first marker that is actually on the page 9if there is
one) (TeX's \firstmark) is first-starting-within-page

Also I lied about the seep you don't want to keep all three items
together, just want the first marker and the line kept together,

<marker (line)/>
...
...
...
A
...
<marker (empty)/>(keep together)<line/>
B
<marker (line)/>
...
C
...

so if the page breaks at point A or C then when the header retrieves the
first-including-carryover marker then it will contain a line

if the page breaks at point B then the first-including-carryover marker
will be empty and so no line will appear when this is used in the