A flexible multi-level UL/LI constructor

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tags. In short,
without href's, classes and ID's, an example of two menus follows below. In
this case the first menu has three levels and the second has four levels:









The above first-level UL's/LI's ("Subject 1" and "Subject 2"), always
contain only one link in it's own level, followed directly by the
opening of a second-level nested UL. This allows CSS to style all others
initially as hidden, until the first level heading is hovered. But this
posting is not about CSS and so I have excluded any such code. However,
should anyone want the accompanying CSS, I would be happy to post
it here. In fact, different types of CSS menus can be built upon the same
or similar type of UL/LI structures and these can naturally only work as
expected if the correct list structures are in place to start with.

The above examples shows the basic UL/LI nesting which the Perl script needs
to generate. However, some additional details needs to be considered to know
exactly what type of coding methods may best serve the particular purpose.

For example, the Perl script needs to recognize which LI's are followed by a
nested UL and print such entries with a specific HTML class:

This allows CSS to place a visual indicator, such as, a small arrow (>)
next to the linked area from where sub-menus unfold when hovered. For
example, when hovering Sub heading 1.3, it's nested sub-menu, including
Subject 1.3.1 and 1.3.2, appear directly to the right of the hovered area:

+----------------------------------------------------------- ------
| Heading 1 > | Heading 2 > | Heading 3 > | etc.
+----------------------------------------------------------- --
| Subject 1.1 |
+-------------------+
| Subject 1.2 |
+-------------------+----------------+
| Sub heading 1.3 > | Subject 1.3.1 |
+-------------------+----------------+
| Subject 1.4 | Subject 1.3.2 |
+-------------------+----------------+
| Subject 1.5 |
+-------------------+

The Perl program will also need to know where within a menu the current HTML
page is represented by traversing the various href values in arrays or
hashes. The current page is identified by a CGI environment variable as:

$current::page = $ENV{DOCUMENT_NAME} || 'undefined';

All HTML documents will exist in one directory level (DocumentRoot) and no
page will be linked to twice from the navigation menus. Therefore, a
same DOCUMENT_NAME conflict will never occur in any of the Perl references.

The LI entry matching the current document should appear as a non-link and
with a unique HTML ID. For example, if the $current::page matches
subject1.3.1.html, then that entry should be printed in the menu as:

Subject 1.3.1

Furthermore, the program will need to be aware of the navigational pathway,
via the arrays or hashes, so it can:

1) Return a text string that displays where the user is, so if the current
page is subject1.3.1.html, then this string would become:

You are in: Heading 1 > Sub heading 1.3 > Subject 1.3.1

2) Output a specific HTML class in the relevant href tags in the pathway, so
when the current page is subject1.3.1.html, a class, e.g. "PATH", would
apply to the entries at the nesting positions that lead up to the current
page. In this case, these two separate HTML tags would appear as:





What signifies pathway LI's is that they can only exist directly after the
opening of LI's with opening UL's before the corresponding LI is closed.
Heading 1 and Sub heading 1.3 in this case are both nesting points and the
pathway to the current page.

Apart from the existence of the menu header, subheading1.3.html will not
present any special content. These type of pages only summarize content
that exist on the sub-menu pages which they represent. Such pathway pages,
including those at first levels, i.e. heading1.html and heading2.html, fill
the same type of purpose in this navigation system, i.e. they are simply
Tables of Contents. Anyhow, this has more to do with the site's content
organization than with the actual functions of the Perl program itself.

Would some kind of multi-level hash arrays, perhaps using Tie::IXHash, be
an appropriate method to generate these type of menu lists?

The procedure is only meant to output dynamically generated menus across all
pages of a site through SSI within a localhost environment. In other words,
the script will not run for each and every page request in a real web
server situation, so no system performance limitations apply. A different
procedure will save all pages in static form to transfer onto a web server.

The projects objective is to maintain a navigation menu across a site via
one Perl script, allowing for navigation links of each separate menu to be
easily modified across the site, including the varying levels of nesting.

In summary, the Perl program should ideally do the all the following:

1) Generate the multi-level UL/LI structure defined in hashes or arrays.
2) Print the current page menu entry differently from others.
3) Identify and print LI's of nesting points differently, as well as return
the navigational pathway string.

What would be a good way to glue these points together? How can the first
point be constructed with a suitable loop for example?

Any ideas, including barebone code examples, that can help lead me in the
right direction, would be greatly appreciated!

Many thanks,
Tuxedo

--
One thing the inventors can't seem to get the bugs out of is fresh paint.