--- loncom/interface/lonnavmaps.pm	2001/10/31 17:44:42	1.19
+++ loncom/interface/lonnavmaps.pm	2003/08/21 18:29:54	1.219.2.1
@@ -1,6 +1,30 @@
 # The LearningOnline Network with CAPA
 # Navigate Maps Handler
 #
+# $Id: lonnavmaps.pm,v 1.219.2.1 2003/08/21 18:29:54 albertel Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
 # (Page Handler
 #
 # (TeX Content Handler
@@ -10,62 +34,2001 @@
 # 10/02,10/10,10/14,10/16,10/18,10/19,10/31,11/6,11/14,11/16 Gerd Kortemeyer)
 #
 # 3/1/1,6/1,17/1,29/1,30/1,2/8,9/21,9/24,9/25 Gerd Kortemeyer
+# YEAR=2002
+# 1/1 Gerd Kortemeyer
+# Oct-Nov Jeremy Bowers
+# YEAR=2003
+# Jeremy Bowers ... lots of days
 
 package Apache::lonnavmaps;
 
 use strict;
 use Apache::Constants qw(:common :http);
-use Apache::lonnet();
 use Apache::loncommon();
-use HTML::TokeParser;
+use Apache::lonmenu();
+use POSIX qw (floor strftime);
+use Data::Dumper; # for debugging, not always used
+
+# symbolic constants
+sub SYMB { return 1; }
+sub URL { return 2; }
+sub NOTHING { return 3; }
+
+# Some data
+
+my $resObj = "Apache::lonnavmaps::resource";
+
+# Keep these mappings in sync with lonquickgrades, which uses the colors
+# instead of the icons.
+my %statusIconMap = 
+    ( $resObj->NETWORK_FAILURE    => '',
+      $resObj->NOTHING_SET        => '',
+      $resObj->CORRECT            => 'navmap.correct.gif',
+      $resObj->EXCUSED            => 'navmap.correct.gif',
+      $resObj->PAST_DUE_NO_ANSWER => 'navmap.wrong.gif',
+      $resObj->PAST_DUE_ANSWER_LATER => 'navmap.wrong.gif',
+      $resObj->ANSWER_OPEN        => 'navmap.wrong.gif',
+      $resObj->OPEN_LATER         => '',
+      $resObj->TRIES_LEFT         => 'navmap.open.gif',
+      $resObj->INCORRECT          => 'navmap.wrong.gif',
+      $resObj->OPEN               => 'navmap.open.gif',
+      $resObj->ATTEMPTED          => 'navmap.ellipsis.gif',
+      $resObj->ANSWER_SUBMITTED   => 'navmap.ellipsis.gif' );
+
+my %iconAltTags = 
+    ( 'navmap.correct.gif' => 'Correct',
+      'navmap.wrong.gif'   => 'Incorrect',
+      'navmap.open.gif'    => 'Open' );
+
+# Defines a status->color mapping, null string means don't color
+my %colormap = 
+    ( $resObj->NETWORK_FAILURE        => '',
+      $resObj->CORRECT                => '',
+      $resObj->EXCUSED                => '#3333FF',
+      $resObj->PAST_DUE_ANSWER_LATER  => '',
+      $resObj->PAST_DUE_NO_ANSWER     => '',
+      $resObj->ANSWER_OPEN            => '#006600',
+      $resObj->OPEN_LATER             => '',
+      $resObj->TRIES_LEFT             => '',
+      $resObj->INCORRECT              => '',
+      $resObj->OPEN                   => '',
+      $resObj->NOTHING_SET            => '',
+      $resObj->ATTEMPTED              => '',
+      $resObj->ANSWER_SUBMITTED       => ''
+      );
+# And a special case in the nav map; what to do when the assignment
+# is not yet done and due in less then 24 hours
+my $hurryUpColor = "#FF0000";
+
+sub handler {
+    my $r = shift;
+    real_handler($r);
+}
+
+sub real_handler {
+    my $r = shift;
+
+    # Handle header-only request
+    if ($r->header_only) {
+        if ($ENV{'browser.mathml'}) {
+            $r->content_type('text/xml');
+        } else {
+            $r->content_type('text/html');
+        }
+        $r->send_http_header;
+        return OK;
+    }
+
+    # Send header, don't cache this page
+    if ($ENV{'browser.mathml'}) {
+        $r->content_type('text/xml');
+    } else {
+        $r->content_type('text/html');
+    }
+    &Apache::loncommon::no_cache($r);
+    $r->send_http_header;
+
+    # Create the nav map
+    my $navmap = Apache::lonnavmaps::navmap->new(
+                        $ENV{"request.course.fn"}.".db",
+                        $ENV{"request.course.fn"}."_parms.db", 1, 1);
+
+
+    if (!defined($navmap)) {
+        my $requrl = $r->uri;
+        $ENV{'user.error.msg'} = "$requrl:bre:0:0:Course not initialized";
+        return HTTP_NOT_ACCEPTABLE;
+    }
+
+    $r->print("<html><head>\n");
+    $r->print("<title>Navigate Course Contents</title>");
+# ------------------------------------------------------------ Get query string
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['register']);
+    
+# ----------------------------------------------------- Force menu registration
+    my $addentries='';
+    if ($ENV{'form.register'}) {
+       $addentries=' onLoad="'.&Apache::lonmenu::loadevents().
+	   '" onUnload="'.&Apache::lonmenu::unloadevents().'"';
+       $r->print(&Apache::lonmenu::registerurl(1));
+    }
+
+    # Header
+    $r->print('</head>'.
+              &Apache::loncommon::bodytag('Navigate Course Contents','',
+                                    $addentries,'','',$ENV{'form.register'}));
+    $r->print('<script>window.focus();</script>');
+
+    $r->rflush();
+
+    # Now that we've displayed some stuff to the user, init the navmap
+    $navmap->init();
+
+    $r->rflush();
+
+    # Check that it's defined
+    if (!($navmap->courseMapDefined())) {
+        $r->print('<font size="+2" color="red">Coursemap undefined.</font>' .
+                  '</body></html>');
+        return OK;
+    }
+
+    # See if there's only one map in the top-level, if we don't
+    # already have a filter... if so, automatically display it
+    if ($ENV{QUERY_STRING} !~ /filter/) {
+        my $iterator = $navmap->getIterator(undef, undef, undef, 0);
+        my $depth = 1;
+        $iterator->next();
+        my $curRes = $iterator->next();
+        my $sequenceCount = 0;
+        my $sequenceId;
+        while ($depth > 0) {
+            if ($curRes == $iterator->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $iterator->END_MAP()) { $depth--; }
+            
+            if (ref($curRes) && $curRes->is_sequence()) {
+                $sequenceCount++;
+                $sequenceId = $curRes->map_pc();
+            }
+            
+            $curRes = $iterator->next();
+        }
+        
+        if ($sequenceCount == 1) {
+            # The automatic iterator creation in the render call 
+            # will pick this up. We know the condition because
+            # the defined($ENV{'form.filter'}) also ensures this
+            # is a fresh call.
+            $ENV{'form.filter'} = "$sequenceId";
+        }
+    }
+
+    my $jumpToFirstHomework = 0;
+    # Check to see if the student is jumping to next open, do-able problem
+    if ($ENV{QUERY_STRING} eq 'jumpToFirstHomework') {
+        $jumpToFirstHomework = 1;
+        # Find the next homework problem that they can do.
+        my $iterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $depth = 1;
+        $iterator->next();
+        my $curRes = $iterator->next();
+        my $foundDoableProblem = 0;
+        my $problemRes;
+        
+        while ($depth > 0 && !$foundDoableProblem) {
+            if ($curRes == $iterator->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $iterator->END_MAP()) { $depth--; }
+
+            if (ref($curRes) && $curRes->is_problem()) {
+                my $status = $curRes->status();
+                if ($curRes->completable()) {
+                    $problemRes = $curRes;
+                    $foundDoableProblem = 1;
+
+                    # Pop open all previous maps
+                    my $stack = $iterator->getStack();
+                    pop @$stack; # last resource in the stack is the problem
+                                 # itself, which we don't need in the map stack
+                    my @mapPcs = map {$_->map_pc()} @$stack;
+                    $ENV{'form.filter'} = join(',', @mapPcs);
+
+                    # Mark as both "here" and "jump"
+                    $ENV{'form.postsymb'} = $curRes->symb();
+                }
+            }
+        } continue {
+            $curRes = $iterator->next();
+        }
+
+        # If we found no problems, print a note to that effect.
+        if (!$foundDoableProblem) {
+            $r->print("<font size='+2'>All homework assignments have been completed.</font><br /><br />");
+        }
+    } else {
+        $r->print("<a href='navmaps?jumpToFirstHomework'>" .
+                  "Go To My First Homework Problem</a>&nbsp;&nbsp;&nbsp;&nbsp;");
+    }
+
+    my $suppressEmptySequences = 0;
+    my $filterFunc = undef;
+    my $resource_no_folder_link = 0;
+
+    # Display only due homework.
+    my $showOnlyHomework = 0;
+    if ($ENV{QUERY_STRING} eq 'showOnlyHomework') {
+        $showOnlyHomework = 1;
+        $suppressEmptySequences = 1;
+        $filterFunc = sub { my $res = shift; 
+                            return $res->completable() || $res->is_map();
+                        };
+        $r->print("<p><font size='+2'>Uncompleted Homework</font></p>");
+        $ENV{'form.filter'} = '';
+        $ENV{'form.condition'} = 1;
+	$resource_no_folder_link = 1;
+    } else {
+        $r->print("<a href='navmaps?showOnlyHomework'>" .
+                  "Show Only Uncompleted Homework</a>&nbsp;&nbsp;&nbsp;&nbsp;");
+    }
+
+    # renderer call
+    my $renderArgs = { 'cols' => [0,1,2,3],
+                       'url' => '/adm/navmaps',
+                       'navmap' => $navmap,
+                       'suppressNavmap' => 1,
+                       'suppressEmptySequences' => $suppressEmptySequences,
+                       'filterFunc' => $filterFunc,
+		       'resource_no_folder_link' => $resource_no_folder_link,
+                       'r' => $r};
+    my $render = render($renderArgs);
+    $navmap->untieHashes();
+
+    # If no resources were printed, print a reassuring message so the
+    # user knows there was no error.
+    if ($renderArgs->{'counter'} == 0) {
+        if ($showOnlyHomework) {
+            $r->print("<p><font size='+1'>All homework is currently completed.</font></p>");
+        } else { # both jumpToFirstHomework and normal use the same: course must be empty
+            $r->print("<p><font size='+1'>This course is empty.</font></p>");
+        }
+    }
+
+    $r->print("</body></html>");
+    $r->rflush();
+
+    return OK;
+}
+
+# Convenience functions: Returns a string that adds or subtracts
+# the second argument from the first hash, appropriate for the 
+# query string that determines which folders to recurse on
+sub addToFilter {
+    my $hashIn = shift;
+    my $addition = shift;
+    my %hash = %$hashIn;
+    $hash{$addition} = 1;
+
+    return join (",", keys(%hash));
+}
+
+sub removeFromFilter {
+    my $hashIn = shift;
+    my $subtraction = shift;
+    my %hash = %$hashIn;
+
+    delete $hash{$subtraction};
+    return join(",", keys(%hash));
+}
+
+# Convenience function: Given a stack returned from getStack on the iterator,
+# return the correct src() value.
+# Later, this should add an anchor when we start putting anchors in pages.
+sub getLinkForResource {
+    my $stack = shift;
+    my $res;
+
+    # Check to see if there are any pages in the stack
+    foreach $res (@$stack) {
+        if (defined($res) && $res->is_page()) {
+            return $res->src();
+        }
+    }
+
+    # Failing that, return the src of the last resource that is defined
+    # (when we first recurse on a map, it puts an undefined resource
+    # on the bottom because $self->{HERE} isn't defined yet, and we
+    # want the src for the map anyhow)
+    foreach (@$stack) {
+        if (defined($_)) { $res = $_; }
+    }
+
+    return $res->src();
+}
+
+# Convenience function: This seperates the logic of how to create
+# the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned",
+# etc.) into a seperate function. It takes a resource object as the
+# first parameter, and the part number of the resource as the second.
+# It's basically a big switch statement on the status of the resource.
+
+sub getDescription {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
+
+    if ($status == $res->NETWORK_FAILURE) { 
+        return "Having technical difficulties; please check status later"; 
+    }
+    if ($status == $res->NOTHING_SET) {
+        return "Not currently assigned.";
+    }
+    if ($status == $res->OPEN_LATER) {
+        return "Open " . timeToHumanString($res->opendate($part));
+    }
+    if ($status == $res->OPEN) {
+        if ($res->duedate($part)) {
+            return "Due " . timeToHumanString($res->duedate($part));
+        } else {
+            return "Open, no due date";
+        }
+    }
+    if ($status == $res->PAST_DUE_ANSWER_LATER) {
+        return "Answer open " . timeToHumanString($res->answerdate($part));
+    }
+    if ($status == $res->PAST_DUE_NO_ANSWER) {
+        return "Was due " . timeToHumanString($res->duedate($part));
+    }
+    if ($status == $res->ANSWER_OPEN) {
+        return "Answer available";
+    }
+    if ($status == $res->EXCUSED) {
+        return "Excused by instructor";
+    }
+    if ($status == $res->ATTEMPTED) {
+        return "Answer submitted, not yet graded.";
+    }
+    if ($status == $res->TRIES_LEFT) {
+        my $tries = $res->tries($part);
+        my $maxtries = $res->maxtries($part);
+        my $triesString = "";
+        if ($tries && $maxtries) {
+            $triesString = "<font size=\"-1\"><i>($tries of $maxtries tries used)</i></font>";
+            if ($maxtries > 1 && $maxtries - $tries == 1) {
+                $triesString = "<b>$triesString</b>";
+            }
+        }
+        if ($res->duedate()) {
+            return "Due " . timeToHumanString($res->duedate($part)) .
+                " $triesString";
+        } else {
+            return "No due date $triesString";
+        }
+    }
+    if ($status == $res->ANSWER_SUBMITTED) {
+        return 'Answer submitted';
+    }
+}
+
+# Convenience function, so others can use it: Is the problem due in less then
+# 24 hours, and still can be done?
+
+sub dueInLessThen24Hours {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
+
+    return ($status == $res->OPEN() ||
+            $status == $res->TRIES_LEFT()) &&
+           $res->duedate() && $res->duedate() < time()+(24*60*60) &&
+           $res->duedate() > time();
+}
+
+# Convenience function, so others can use it: Is there only one try remaining for the
+# part, with more then one try to begin with, not due yet and still can be done?
+sub lastTry {
+    my $res = shift;
+    my $part = shift;
+
+    my $tries = $res->tries($part);
+    my $maxtries = $res->maxtries($part);
+    return $tries && $maxtries && $maxtries > 1 &&
+        $maxtries - $tries == 1 && $res->duedate() &&
+        $res->duedate() > time();
+}
+
+# This puts a human-readable name on the ENV variable.
+
+sub advancedUser {
+    return $ENV{'request.role.adv'};
+}
+
+
+# timeToHumanString takes a time number and converts it to a
+# human-readable representation, meant to be used in the following
+# manner:
+# print "Due $timestring"
+# print "Open $timestring"
+# print "Answer available $timestring"
+# Very, very, very, VERY English-only... goodness help a localizer on
+# this func...
+sub timeToHumanString {
+    my ($time) = @_;
+    # zero, '0' and blank are bad times
+    if (!$time) {
+        return 'never';
+    }
+
+    my $now = time();
+
+    my @time = localtime($time);
+    my @now = localtime($now);
+
+    # Positive = future
+    my $delta = $time - $now;
+
+    my $minute = 60;
+    my $hour = 60 * $minute;
+    my $day = 24 * $hour;
+    my $week = 7 * $day;
+    my $inPast = 0;
+
+    # Logic in comments:
+    # Is it now? (extremely unlikely)
+    if ( $delta == 0 ) {
+        return "this instant";
+    }
+
+    if ($delta < 0) {
+        $inPast = 1;
+        $delta = -$delta;
+    }
+
+    if ( $delta > 0 ) {
+
+        my $tense = $inPast ? " ago" : "";
+        my $prefix = $inPast ? "" : "in ";
+        
+        # Less then a minute
+        if ( $delta < $minute ) {
+            if ($delta == 1) { return "${prefix}1 second$tense"; }
+            return "$prefix$delta seconds$tense";
+        }
+
+        # Less then an hour
+        if ( $delta < $hour ) {
+            # If so, use minutes
+            my $minutes = floor($delta / 60);
+            if ($minutes == 1) { return "${prefix}1 minute$tense"; }
+            return "$prefix$minutes minutes$tense";
+        }
+        
+        # Is it less then 24 hours away? If so,
+        # display hours + minutes
+        if ( $delta < $hour * 24) {
+            my $hours = floor($delta / $hour);
+            my $minutes = floor(($delta % $hour) / $minute);
+            my $hourString = "$hours hours";
+            my $minuteString = ", $minutes minutes";
+            if ($hours == 1) {
+                $hourString = "1 hour";
+            }
+            if ($minutes == 1) {
+                $minuteString = ", 1 minute";
+            }
+            if ($minutes == 0) {
+                $minuteString = "";
+            }
+            return "$prefix$hourString$minuteString$tense";
+        }
+
+        # Less then 5 days away, display day of the week and
+        # HH:MM
+        if ( $delta < $day * 5 ) {
+            my $timeStr = strftime("%A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/midnight/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return ($inPast ? "last " : "next ") .
+                $timeStr;
+        }
+        
+        # Is it this year?
+        if ( $time[5] == $now[5]) {
+            # Return on Month Day, HH:MM meridian
+            my $timeStr = strftime("on %A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/midnight/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return $timeStr;
+        }
+
+        # Not this year, so show the year
+        my $timeStr = strftime("on %A, %b %e %G at %I:%M %P", localtime($time));
+        $timeStr =~ s/12:00 am/midnight/;
+        $timeStr =~ s/12:00 pm/noon/;
+        return $timeStr;
+    }
+}
+
+
+=pod
+
+=head1 NAME
+
+Apache::lonnavmap - Subroutines to handle and render the navigation
+    maps
+
+=head1 SYNOPSIS
+
+The main handler generates the navigational listing for the course,
+the other objects export this information in a usable fashion for
+other modules.
+
+=head1 OVERVIEW
+
+X<lonnavmaps, overview> When a user enters a course, LON-CAPA examines the
+course structure and caches it in what is often referred to as the
+"big hash" X<big hash>. You can see it if you are logged into
+LON-CAPA, in a course, by going to /adm/test. (You may need to
+tweak the /home/httpd/lonTabs/htpasswd file to view it.) The
+content of the hash will be under the heading "Big Hash".
+
+Big Hash contains, among other things, how resources are related
+to each other (next/previous), what resources are maps, which 
+resources are being chosen to not show to the student (for random
+selection), and a lot of other things that can take a lot of time
+to compute due to the amount of data that needs to be collected and
+processed.
+
+Apache::lonnavmaps provides an object model for manipulating this
+information in a higher-level fashion then directly manipulating 
+the hash. It also provides access to several auxilary functions 
+that aren't necessarily stored in the Big Hash, but are a per-
+resource sort of value, like whether there is any feedback on 
+a given resource.
+
+Apache::lonnavmaps also abstracts away branching, and someday, 
+conditions, for the times where you don't really care about those
+things.
+
+Apache::lonnavmaps also provides fairly powerful routines for
+rendering navmaps, and last but not least, provides the navmaps
+view for when the user clicks the NAV button.
+
+B<Note>: Apache::lonnavmaps I<only> works for the "currently
+logged in user"; if you want things like "due dates for another
+student" lonnavmaps can not directly retrieve information like
+that. You need the EXT function. This module can still help,
+because many things, such as the course structure, are constant
+between users, and Apache::lonnavmaps can help by providing
+symbs for the EXT call.
+
+The rest of this file will cover the provided rendering routines, 
+which can often be used without fiddling with the navmap object at
+all, then documents the Apache::lonnavmaps::navmap object, which
+is the key to accessing the Big Hash information, covers the use
+of the Iterator (which provides the logic for traversing the 
+somewhat-complicated Big Hash data structure), documents the
+Apache::lonnavmaps::Resource objects that are returned by 
+
+=head1 Subroutine: render
+
+The navmap renderer package provides a sophisticated rendering of the
+standard navigation maps interface into HTML. The provided nav map
+handler is actually just a glorified call to this.
+
+Because of the large number of parameters this function accepts,
+instead of passing it arguments as is normal, pass it in an anonymous
+hash with the desired options.
+
+The package provides a function called 'render', called as
+Apache::lonnavmaps::render({}).
+
+=head2 Overview of Columns
+
+The renderer will build an HTML table for the navmap and return
+it. The table is consists of several columns, and a row for each
+resource (or possibly each part). You tell the renderer how many
+columns to create and what to place in each column, optionally using
+one or more of the prepared columns, and the renderer will assemble
+the table.
+
+Any additional generally useful column types should be placed in the
+renderer code here, so anybody can use it anywhere else. Any code
+specific to the current application (such as the addition of <input>
+elements in a column) should be placed in the code of the thing using
+the renderer.
+
+At the core of the renderer is the array reference COLS (see Example
+section below for how to pass this correctly). The COLS array will
+consist of entries of one of two types of things: Either an integer
+representing one of the pre-packaged column types, or a sub reference
+that takes a resource reference, a part number, and a reference to the
+argument hash passed to the renderer, and returns a string that will
+be inserted into the HTML representation as it.
+
+All other parameters are ways of either changing how the columns
+are printing, or which rows are shown.
+
+The pre-packaged column names are refered to by constants in the
+Apache::lonnavmaps namespace. The following currently exist:
+
+=over 4
+
+=item * B<Apache::lonnavmaps::resource>:
+
+The general info about the resource: Link, icon for the type, etc. The
+first column in the standard nav map display. This column provides the
+indentation effect seen in the B<NAV> screen. This column also accepts
+the following parameters in the renderer hash:
+
+=over 4
+
+=item * B<resource_nolink>: default false
+
+If true, the resource will not be linked. By default, all non-folder
+resources are linked.
+
+=item * B<resource_part_count>: default true
+
+If true, the resource will show a part count B<if> the full
+part list is not displayed. (See "condense_parts" later.) If false,
+the resource will never show a part count.
+
+=item * B<resource_no_folder_link>:
+
+If true, the resource's folder will not be clickable to open or close
+it. Default is false. True implies printCloseAll is false, since you
+can't close or open folders when this is on anyhow.
+
+=back
+
+=item B<Apache::lonnavmaps::communication_status>:
+
+Whether there is discussion on the resource, email for the user, or
+(lumped in here) perl errors in the execution of the problem. This is
+the second column in the main nav map.
+
+=item B<Apache::lonnavmaps::quick_status>:
+
+An icon for the status of a problem, with five possible states:
+Correct, incorrect, open, awaiting grading (for a problem where the
+computer's grade is suppressed, or the computer can't grade, like
+essay problem), or none (not open yet, not a problem). The
+third column of the standard navmap.
+
+=item B<Apache::lonnavmaps::long_status>:
+
+A text readout of the details of the current status of the problem,
+such as "Due in 22 hours". The fourth column of the standard navmap.
+
+=back
+
+If you add any others please be sure to document them here.
+
+An example of a column renderer that will show the ID number of a
+resource, along with the part name if any:
+
+ sub { 
+  my ($resource, $part, $params) = @_;   
+  if ($part) { return '<td>' . $resource->{ID} . ' ' . $part . '</td>'; }
+  return '<td>' . $resource->{ID} . '</td>';
+ }
+
+Note these functions are responsible for the TD tags, which allow them
+to override vertical and horizontal alignment, etc.
+
+=head2 Parameters
+
+Minimally, you should be
+able to get away with just using 'cols' (to specify the columns
+shown), 'url' (necessary for the folders to link to the current screen
+correctly), and possibly 'queryString' if your app calls for it. In
+that case, maintaining the state of the folders will be done
+automatically.
+
+=over 4
+
+=item * B<iterator>: default: constructs one from %ENV
+
+A reference to a fresh ::iterator to use from the navmaps. The
+rendering will reflect the options passed to the iterator, so you can
+use that to just render a certain part of the course, if you like. If
+one is not passed, the renderer will attempt to construct one from
+ENV{'form.filter'} and ENV{'form.condition'} information, plus the
+'iterator_map' parameter if any.
+
+=item * B<iterator_map>: default: not used
+
+If you are letting the renderer do the iterator handling, you can
+instruct the renderer to render only a particular map by passing it
+the source of the map you want to process, like
+'/res/103/jerf/navmap.course.sequence'.
+
+=item * B<navmap>: default: constructs one from %ENV
+
+A reference to a navmap, used only if an iterator is not passed in. If
+this is necessary to make an iterator but it is not passed in, a new
+one will be constructed based on ENV info. This is useful to do basic
+error checking before passing it off to render.
+
+=item * B<r>: default: must be passed in
+
+The standard Apache response object. This must be passed to the
+renderer or the course hash will be locked.
+
+=item * B<cols>: default: empty (useless)
+
+An array reference
+
+=item * B<showParts>:default true
+
+A flag. If true, a line for the resource itself, and a line
+for each part will be displayed. If not, only one line for each
+resource will be displayed.
+
+=item * B<condenseParts>: default true
+
+A flag. If true, if all parts of the problem have the same
+status and that status is Nothing Set, Correct, or Network Failure,
+then only one line will be displayed for that resource anyhow. If no,
+all parts will always be displayed. If showParts is 0, this is
+ignored.
+
+=item * B<jumpCount>: default: determined from %ENV
+
+A string identifying the URL to place the anchor 'curloc' at.
+It is the responsibility of the renderer user to
+ensure that the #curloc is in the URL. By default, determined through
+the use of the ENV{} 'jump' information, and should normally "just
+work" correctly.
+
+=item * B<here>: default: empty string
+
+A Symb identifying where to place the 'here' marker. The empty
+string means no marker.
+
+=item * B<indentString>: default: 25 pixel whitespace image
+
+A string identifying the indentation string to use. 
+
+=item * B<queryString>: default: empty
+
+A string which will be prepended to the query string used when the
+folders are opened or closed. You can use this to pass
+application-specific values.
+
+=item * B<url>: default: none
+
+The url the folders will link to, which should be the current
+page. Required if the resource info column is shown, and you 
+are allowing the user to open and close folders.
+
+=item * B<currentJumpIndex>: default: no jumping
+
+Describes the currently-open row number to cause the browser to jump
+to, because the user just opened that folder. By default, pulled from
+the Jump information in the ENV{'form.*'}.
+
+=item * B<printKey>: default: false
+
+If true, print the key that appears on the top of the standard
+navmaps.
+
+=item * B<printCloseAll>: default: true
+
+If true, print the "Close all folders" or "open all folders"
+links.
+
+=item * B<filterFunc>: default: sub {return 1;} (accept everything)
+
+A function that takes the resource object as its only parameter and
+returns a true or false value. If true, the resource is displayed. If
+false, it is simply skipped in the display.
+
+=item * B<suppressEmptySequences>: default: false
+
+If you're using a filter function, and displaying sequences to orient
+the user, then frequently some sequences will be empty. Setting this to
+true will cause those sequences not to display, so as not to confuse the
+user into thinking that if the sequence is there there should be things
+under it; for example, see the "Show Uncompleted Homework" view on the
+B<NAV> screen.
+
+=item * B<suppressNavmaps>: default: false
+
+If true, will not display Navigate Content resources. 
+
+=back
+
+=head2 Additional Info
+
+In addition to the parameters you can pass to the renderer, which will
+be passed through unchange to the column renderers, the renderer will
+generate the following information which your renderer may find
+useful:
+
+=over 4
+
+=item * B<counter>: 
+
+Contains the number of rows printed. Useful after calling the render 
+function, as you can detect whether anything was printed at all.
+
+=item * B<isNewBranch>:
+
+Useful for renderers: If this resource is currently the first resource
+of a new branch, this will be true. The Resource column (leftmost in the
+navmaps screen) uses this to display the "new branch" icon 
+
+=back
+
+=cut
+
+sub resource { return 0; }
+sub communication_status { return 1; }
+sub quick_status { return 2; }
+sub long_status { return 3; }
+
+# Data for render_resource
+
+sub render_resource {
+    my ($resource, $part, $params) = @_;
+
+    my $nonLinkedText = ''; # stuff after resource title not in link
+
+    my $link = $params->{"resourceLink"};
+    my $src = $resource->src();
+    my $it = $params->{"iterator"};
+    my $filter = $it->{FILTER};
+
+    my $title = $resource->compTitle();
+    if ($src =~ /^\/uploaded\//) {
+        $nonLinkedText=$title;
+        $title = '';
+    }
+    my $partLabel = "";
+    my $newBranchText = "";
+    
+    # If this is a new branch, label it so
+    if ($params->{'isNewBranch'}) {
+        $newBranchText = "<img src='/adm/lonIcons/branch.gif' border='0' />";
+    }
+
+    # links to open and close the folder
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
+
+    # Default icon: unknown page
+    my $icon = "<img src='/adm/lonIcons/unknown.gif' alt='' border='0' />";
+    
+    if ($resource->is_problem()) {
+        if ($part eq '0' || $params->{'condensed'}) {
+            $icon = '<img src="/adm/lonIcons/problem.gif" alt="" border="0" />';
+        } else {
+            $icon = $params->{'indentString'};
+        }
+    } else {
+	my $curfext= (split (/\./,$resource->src))[-1];
+	my $embstyle = &Apache::loncommon::fileembstyle($curfext);
+	# The unless conditional that follows is a bit of overkill
+	if (!(!defined($embstyle) || $embstyle eq 'unk' || $embstyle eq 'hdn')) {
+	    $icon = "<img src='/adm/lonIcons/$curfext.gif' alt='' border='0' />";
+	}
+    }
+
+    # Display the correct map icon to open or shut map
+    if ($resource->is_map()) {
+        my $mapId = $resource->map_pc();
+        my $nowOpen = !defined($filter->{$mapId});
+        if ($it->{CONDITION}) {
+            $nowOpen = !$nowOpen;
+        }
+
+	my $folderType = $resource->is_sequence() ? 'folder' : 'page';
+
+        if (!$params->{'resource_no_folder_link'}) {
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') . '.gif';
+            $icon = "<img src='/adm/lonIcons/$icon' alt='' border='0' />";
+
+            $linkopen = "<a href='" . $params->{'url'} . '?' . 
+                $params->{'queryString'} . '&filter=';
+            $linkopen .= ($nowOpen xor $it->{CONDITION}) ?
+                addToFilter($filter, $mapId) :
+                removeFromFilter($filter, $mapId);
+            $linkopen .= "&condition=" . $it->{CONDITION} . '&hereType='
+                . $params->{'hereType'} . '&here=' .
+                &Apache::lonnet::escape($params->{'here'}) . 
+                '&jump=' .
+                &Apache::lonnet::escape($resource->symb()) . 
+                "&folderManip=1'>";
+        } else {
+            # Don't allow users to manipulate folder
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') .
+                '.nomanip.gif';
+            $icon = "<img src='/adm/lonIcons/$icon' alt='' border='0' />";
+
+            $linkopen = "";
+            $linkclose = "";
+        }
+    }
+
+    if ($resource->randomout()) {
+        $nonLinkedText .= ' <i>(hidden)</i> ';
+    }
+    
+    # We're done preparing and finally ready to start the rendering
+    my $result = "<td align='left' valign='center'>";
+
+    my $indentLevel = $params->{'indentLevel'};
+    if ($newBranchText) { $indentLevel--; }
+
+    # print indentation
+    for (my $i = 0; $i < $indentLevel; $i++) {
+        $result .= $params->{'indentString'};
+    }
+
+    # Decide what to display
+    $result .= "$newBranchText$linkopen$icon$linkclose";
+    
+    my $curMarkerBegin = '';
+    my $curMarkerEnd = '';
+
+    # Is this the current resource?
+    if (!$params->{'displayedHereMarker'} && 
+        $resource->symb() eq $params->{'here'} ) {
+        $curMarkerBegin = '<font color="red" size="+2">&gt; </font>';
+        $curMarkerEnd = '<font color="red" size="+2">&lt;</font>';
+        $params->{'displayedHereMarker'} = 1;
+    }
+
+    if ($resource->is_problem() && $part ne '0' && 
+        !$params->{'condensed'}) {
+        $partLabel = " (Part $part)";
+        $title = "";
+    }
+
+    if ($params->{'condensed'} && $resource->countParts() > 1) {
+        $nonLinkedText .= ' (' . $resource->countParts() . ' parts)';
+    }
+
+    if (!$params->{'resource_nolink'} && $src !~ /^\/uploaded\// &&
+	!$resource->is_sequence()) {
+        $result .= "  $curMarkerBegin<a href='$link'>$title$partLabel</a>$curMarkerEnd $nonLinkedText</td>";
+    } else {
+        $result .= "  $curMarkerBegin$title$partLabel$curMarkerEnd $nonLinkedText</td>";
+    }
+
+    return $result;
+}
+
+sub render_communication_status {
+    my ($resource, $part, $params) = @_;
+    my $discussionHTML = ""; my $feedbackHTML = ""; my $errorHTML = "";
+
+    my $link = $params->{"resourceLink"};
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
+
+    if ($resource->hasDiscussion()) {
+        $discussionHTML = $linkopen .
+            '<img border="0" src="/adm/lonMisc/chat.gif" />' .
+            $linkclose;
+    }
+    
+    if ($resource->getFeedback()) {
+        my $feedback = $resource->getFeedback();
+        foreach (split(/\,/, $feedback)) {
+            if ($_) {
+                $feedbackHTML .= '&nbsp;<a href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="/adm/lonMisc/feedback.gif" '
+                    . 'border="0" /></a>';
+            }
+        }
+    }
+    
+    if ($resource->getErrors()) {
+        my $errors = $resource->getErrors();
+        foreach (split(/,/, $errors)) {
+            if ($_) {
+                $errorHTML .= '&nbsp;<a href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="/adm/lonMisc/bomb.gif" '
+                    . 'border="0" /></a>';
+            }
+        }
+    }
+
+    if ($params->{'multipart'} && $part != '0') {
+	$discussionHTML = $feedbackHTML = $errorHTML = '';
+    }
+
+    return "<td width=\"75\" align=\"left\" valign=\"center\">$discussionHTML$feedbackHTML$errorHTML&nbsp;</td>";
+
+}
+sub render_quick_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
+
+    my $link = $params->{"resourceLink"};
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
+
+    if ($resource->is_problem() &&
+        !$firstDisplayed) {
+        my $icon = $statusIconMap{$resource->status($part)};
+        my $alt = $iconAltTags{$icon};
+        if ($icon) {
+            $result .= "<td width='30' valign='center' width='50' align='right'>$linkopen<img width='25' height='25' src='/adm/lonIcons/$icon' border='0' alt='$alt' />$linkclose</td>\n";
+        } else {
+            $result .= "<td width='30'>&nbsp;</td>\n";
+        }
+    } else { # not problem, no icon
+        $result .= "<td width='30'>&nbsp;</td>\n";
+    }
+
+    return $result;
+}
+sub render_long_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "<td align='right' valign='center'>\n";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
+                
+    my $color;
+    if ($resource->is_problem()) {
+        $color = $colormap{$resource->status};
+        
+        if (dueInLessThen24Hours($resource, $part) ||
+            lastTry($resource, $part)) {
+            $color = $hurryUpColor;
+        }
+    }
+    
+    if ($resource->kind() eq "res" &&
+        $resource->is_problem() &&
+        !$firstDisplayed) {
+        if ($color) {$result .= "<font color=\"$color\"><b>"; }
+        $result .= getDescription($resource, $part);
+        if ($color) {$result .= "</b></font>"; }
+    }
+    if ($resource->is_map() && advancedUser() && $resource->randompick()) {
+        $result .= '(randomly select ' . $resource->randompick() .')';
+    }
+
+    # Debugging code
+    #$result .= " " . $resource->awarded($part) . '/' . $resource->weight($part) .
+    #	' - Part: ' . $part;
+
+    $result .= "</td>\n";
+    
+    return $result;
+}
+
+my @preparedColumns = (\&render_resource, \&render_communication_status,
+                       \&render_quick_status, \&render_long_status);
+
+sub setDefault {
+    my ($val, $default) = @_;
+    if (!defined($val)) { return $default; }
+    return $val;
+}
+
+sub render {
+    my $args = shift;
+    &Apache::loncommon::get_unprocessed_cgi($ENV{QUERY_STRING});
+    my $result = '';
+
+    # Configure the renderer.
+    my $cols = $args->{'cols'};
+    if (!defined($cols)) {
+        # no columns, no nav maps.
+        return '';
+    }
+    my $mustCloseNavMap = 0;
+    my $navmap;
+    if (defined($args->{'navmap'})) {
+        $navmap = $args->{'navmap'};
+    }
+
+    my $r = $args->{'r'};
+    my $queryString = $args->{'queryString'};
+    my $jump = $args->{'jump'};
+    my $here = $args->{'here'};
+    my $suppressNavmap = setDefault($args->{'suppressNavmap'}, 0);
+    my $currentJumpDelta = 2; # change this to change how many resources are displayed
+                             # before the current resource when using #current
+
+    # If we were passed 'here' information, we are not rendering
+    # after a folder manipulation, and we were not passed an
+    # iterator, make sure we open the folders to show the "here"
+    # marker
+    my $filterHash = {};
+    # Figure out what we're not displaying
+    foreach (split(/\,/, $ENV{"form.filter"})) {
+        if ($_) {
+            $filterHash->{$_} = "1";
+        }
+    }
+
+    # Filter: Remember filter function and add our own filter: Refuse
+    # to show hidden resources unless the user can see them.
+    my $userCanSeeHidden = advancedUser();
+    my $filterFunc = setDefault($args->{'filterFunc'},
+                                sub {return 1;});
+    if (!$userCanSeeHidden) {
+        # Without renaming the filterfunc, the server seems to go into
+        # an infinite loop
+        my $oldFilterFunc = $filterFunc;
+        $filterFunc = sub { my $res = shift; return !$res->randomout() && 
+                                &$oldFilterFunc($res);};
+    }
+
+    my $condition = 0;
+    if ($ENV{'form.condition'}) {
+        $condition = 1;
+    }
+
+    if (!$ENV{'form.folderManip'} && !defined($args->{'iterator'})) {
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new(
+                        $ENV{"request.course.fn"}.".db",
+                        $ENV{"request.course.fn"}."_parms.db", 1, 1);
+            $mustCloseNavMap = 1;
+        }
+        $navmap->init();
+
+        # Step two: Locate what kind of here marker is necessary
+        # Determine where the "here" marker is and where the screen jumps to.
+
+        if ($ENV{'form.postsymb'}) {
+            $here = $jump = $ENV{'form.postsymb'};
+        } elsif ($ENV{'form.postdata'}) {
+            # couldn't find a symb, is there a URL?
+            my $currenturl = $ENV{'form.postdata'};
+            #$currenturl=~s/^http\:\/\///;
+            #$currenturl=~s/^[^\/]+//;
+            
+            $here = $jump = &Apache::lonnet::symbread($currenturl);
+        }
+
+        # Step three: Ensure the folders are open
+        my $mapIterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $depth = 1;
+        $mapIterator->next(); # discard the first BEGIN_MAP
+        my $curRes = $mapIterator->next();
+        my $found = 0;
+        
+        # We only need to do this if we need to open the maps to show the
+        # current position. This will change the counter so we can't count
+        # for the jump marker with this loop.
+        while ($depth > 0 && !$found) {
+            if ($curRes == $mapIterator->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $mapIterator->END_MAP()) { $depth--; }
+            
+            if (ref($curRes) && $curRes->symb() eq $here) {
+                my $mapStack = $mapIterator->getStack();
+                
+                # Ensure the parent maps are open
+                for my $map (@{$mapStack}) {
+                    if ($condition) {
+                        undef $filterHash->{$map->map_pc()};
+                    } else {
+                        $filterHash->{$map->map_pc()} = 1;
+                    }
+                }
+                $found = 1;
+            }
+            
+            $curRes = $mapIterator->next();
+        }            
+    }        
+
+    if ( !defined($args->{'iterator'}) && $ENV{'form.folderManip'} ) { # we came from a user's manipulation of the nav page
+        # If this is a click on a folder or something, we want to preserve the "here"
+        # from the querystring, and get the new "jump" marker
+        $here = $ENV{'form.here'};
+        $jump = $ENV{'form.jump'};
+    } 
+    
+    my $it = $args->{'iterator'};
+    if (!defined($it)) {
+        # Construct a default iterator based on $ENV{'form.'} information
+        
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new($r, 
+                        $ENV{"request.course.fn"}.".db",
+                        $ENV{"request.course.fn"}."_parms.db", 1, 1);
+            $mustCloseNavMap = 1;
+        }
+        # Paranoia: Make sure it's ready
+        $navmap->init();
+
+        # See if we're being passed a specific map
+        if ($args->{'iterator_map'}) {
+            my $map = $args->{'iterator_map'};
+            $map = $navmap->getResourceByUrl($map);
+            my $firstResource = $map->map_start();
+            my $finishResource = $map->map_finish();
+
+            $args->{'iterator'} = $it = $navmap->getIterator($firstResource, $finishResource, $filterHash, $condition);
+        } else {
+            $args->{'iterator'} = $it = $navmap->getIterator(undef, undef, $filterHash, $condition);
+        }
+    }
+    
+    # (re-)Locate the jump point, if any
+    # Note this does not take filtering or hidden into account... need
+    # to be fixed?
+    my $mapIterator = $navmap->getIterator(undef, undef, $filterHash, 0);
+    my $depth = 1;
+    $mapIterator->next();
+    my $curRes = $mapIterator->next();
+    my $foundJump = 0;
+    my $counter = 0;
+    
+    while ($depth > 0 && !$foundJump) {
+        if ($curRes == $mapIterator->BEGIN_MAP()) { $depth++; }
+        if ($curRes == $mapIterator->END_MAP()) { $depth--; }
+        if (ref($curRes)) { $counter++; }
+        
+        if (ref($curRes) && $jump eq $curRes->symb()) {
+            
+            # This is why we have to use the main iterator instead of the
+            # potentially faster DFS: The count has to be the same, so
+            # the order has to be the same, which DFS won't give us.
+            $args->{'currentJumpIndex'} = $counter;
+            $foundJump = 1;
+        }
+        
+        $curRes = $mapIterator->next();
+    }
+
+    my $showParts = setDefault($args->{'showParts'}, 1);
+    my $condenseParts = setDefault($args->{'condenseParts'}, 1);
+    # keeps track of when the current resource is found,
+    # so we can back up a few and put the anchor above the
+    # current resource
+    my $printKey = $args->{'printKey'};
+    my $printCloseAll = $args->{'printCloseAll'};
+    if (!defined($printCloseAll)) { $printCloseAll = 1; }
+    
+    # Print key?
+    if ($printKey) {
+        $result .= '<table border="0" cellpadding="2" cellspacing="0">';
+        my $date=localtime;
+        $result.='<tr><td align="right" valign="bottom">Key:&nbsp;&nbsp;</td>';
+        if ($navmap->{LAST_CHECK}) {
+            $result .= 
+                '<img src="/adm/lonMisc/chat.gif"> New discussion since '.
+                strftime("%A, %b %e at %I:%M %P", localtime($navmap->{LAST_CHECK})).
+                '</td><td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="/adm/lonMisc/feedback.gif"> New message (click to open)<p>'.
+                '</td>'; 
+        } else {
+            $result .= '<td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="/adm/lonMisc/chat.gif"> Discussions</td><td align="center" valign="bottom">'.
+                '&nbsp;&nbsp;<img src="/adm/lonMisc/feedback.gif"> New message (click to open)'.
+                '</td>'; 
+        }
+
+        $result .= '</tr></table>';
+    }
+
+    if ($printCloseAll && !$args->{'resource_no_folder_link'}) {
+        if ($condition) {
+            $result.="<a href=\"navmaps?condition=0&filter=&$queryString" .
+                "&here=" . Apache::lonnet::escape($here) .
+                "\">Close All Folders</a>";
+        } else {
+            $result.="<a href=\"navmaps?condition=1&filter=&$queryString" .
+                "&here=" . Apache::lonnet::escape($here) . 
+                "\">Open All Folders</a>";
+        }
+        $result .= "<br /><br />\n";
+    }    
+
+    if ($r) {
+        $r->print($result);
+        $r->rflush();
+        $result = "";
+    }
+    # End parameter setting
+            
+    # Data
+    $result .= '<table cellspacing="0" cellpadding="3" border="0" bgcolor="#FFFFFF">' ."\n";
+    my $res = "Apache::lonnavmaps::resource";
+    my %condenseStatuses =
+        ( $res->NETWORK_FAILURE    => 1,
+          $res->NOTHING_SET        => 1,
+          $res->CORRECT            => 1 );
+    my @backgroundColors = ("#FFFFFF", "#F6F6F6");
+
+    # Shared variables
+    $args->{'counter'} = 0; # counts the rows
+    $args->{'indentLevel'} = 0;
+    $args->{'isNewBranch'} = 0;
+    $args->{'condensed'} = 0;    
+    $args->{'indentString'} = setDefault($args->{'indentString'}, "<img src='/adm/lonIcons/whitespace1.gif' width='25' height='1' alt='' border='0' />");
+    $args->{'displayedHereMarker'} = 0;
+
+    # If we're suppressing empty sequences, look for them here. Use DFS for speed,
+    # since structure actually doesn't matter, except what map has what resources.
+    if ($args->{'suppressEmptySequences'}) {
+        my $dfsit = Apache::lonnavmaps::DFSiterator->new($navmap,
+                                                         $it->{FIRST_RESOURCE},
+                                                         $it->{FINISH_RESOURCE},
+                                                         {}, undef, 1);
+        $depth = 0;
+        $dfsit->next();
+        my $curRes = $dfsit->next();
+        while ($depth > -1) {
+            if ($curRes == $dfsit->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $dfsit->END_MAP()) { $depth--; }
+
+            if (ref($curRes)) { 
+                # Parallel pre-processing: Do sequences have non-filtered-out children?
+                if ($curRes->is_map()) {
+                    $curRes->{DATA}->{HAS_VISIBLE_CHILDREN} = 0;
+                    # Sequences themselves do not count as visible children,
+                    # unless those sequences also have visible children.
+                    # This means if a sequence appears, there's a "promise"
+                    # that there's something under it if you open it, somewhere.
+                } else {
+                    # Not a sequence: if it's filtered, ignore it, otherwise
+                    # rise up the stack and mark the sequences as having children
+                    if (&$filterFunc($curRes)) {
+                        for my $sequence (@{$dfsit->getStack()}) {
+                            $sequence->{DATA}->{HAS_VISIBLE_CHILDREN} = 1;
+                        }
+                    }
+                }
+            }
+        } continue {
+            $curRes = $dfsit->next();
+        }
+    }
+
+    my $displayedJumpMarker = 0;
+    # Set up iteration.
+    $depth = 1;
+    $it->next(); # discard initial BEGIN_MAP
+    $curRes = $it->next();
+    my $now = time();
+    my $in24Hours = $now + 24 * 60 * 60;
+    my $rownum = 0;
+
+    # export "here" marker information
+    $args->{'here'} = $here;
+
+    while ($depth > 0) {
+        if ($curRes == $it->BEGIN_MAP()) { $depth++; }
+        if ($curRes == $it->END_MAP()) { $depth--; }
+
+        # Maintain indentation level.
+        if ($curRes == $it->BEGIN_MAP() ||
+            $curRes == $it->BEGIN_BRANCH() ) {
+            $args->{'indentLevel'}++;
+        }
+        if ($curRes == $it->END_MAP() ||
+            $curRes == $it->END_BRANCH() ) {
+            $args->{'indentLevel'}--;
+        }
+        # Notice new branches
+        if ($curRes == $it->BEGIN_BRANCH()) {
+            $args->{'isNewBranch'} = 1;
+        }
+
+        # If this isn't an actual resource, continue on
+        if (!ref($curRes)) {
+            next;
+        }
+
+        # If this has been filtered out, continue on
+        if (!(&$filterFunc($curRes))) {
+            $args->{'isNewBranch'} = 0; # Don't falsely remember this
+            next;
+        } 
+
+        # If this is an empty sequence and we're filtering them, continue on
+        if ($curRes->is_map() && $args->{'suppressEmptySequences'} &&
+            !$curRes->{DATA}->{HAS_VISIBLE_CHILDREN}) {
+            next;
+        }
+
+        # If we're suppressing navmaps and this is a navmap, continue on
+        if ($suppressNavmap && $curRes->src() =~ /^\/adm\/navmaps/) {
+            next;
+        }
+
+        $args->{'counter'}++;
+
+        # Does it have multiple parts?
+        $args->{'multipart'} = 0;
+        $args->{'condensed'} = 0;
+        my @parts;
+            
+        # Decide what parts to show.
+        if ($curRes->is_problem() && $showParts) {
+            @parts = @{$curRes->parts()};
+            $args->{'multipart'} = $curRes->multipart();
+            
+            if ($condenseParts) { # do the condensation
+                if (!$curRes->opendate("0")) {
+                    @parts = ();
+                    $args->{'condensed'} = 1;
+                }
+                if (!$args->{'condensed'}) {
+                    # Decide whether to condense based on similarity
+                    my $status = $curRes->status($parts[0]);
+                    my $due = $curRes->duedate($parts[0]);
+                    my $open = $curRes->opendate($parts[0]);
+                    my $statusAllSame = 1;
+                    my $dueAllSame = 1;
+                    my $openAllSame = 1;
+                    for (my $i = 1; $i < scalar(@parts); $i++) {
+                        if ($curRes->status($parts[$i]) != $status){
+                            $statusAllSame = 0;
+                        }
+                        if ($curRes->duedate($parts[$i]) != $due ) {
+                            $dueAllSame = 0;
+                        }
+                        if ($curRes->opendate($parts[$i]) != $open) {
+                            $openAllSame = 0;
+                        }
+                    }
+                    # $*allSame is true if all the statuses were
+                    # the same. Now, if they are all the same and
+                    # match one of the statuses to condense, or they
+                    # are all open with the same due date, or they are
+                    # all OPEN_LATER with the same open date, display the
+                    # status of the first non-zero part (to get the 'correct'
+                    # status right, since 0 is never 'correct' or 'open').
+                    if (($statusAllSame && defined($condenseStatuses{$status})) ||
+                        ($dueAllSame && $status == $curRes->OPEN && $statusAllSame)||
+                        ($openAllSame && $status == $curRes->OPEN_LATER && $statusAllSame) ){
+                        @parts = ($parts[0]);
+                        $args->{'condensed'} = 1;
+                    }
+                }
+		# Multipart problem with one part: always "condense" (happens
+		#  to match the desirable behavior)
+		if ($curRes->countParts() == 1) {
+		    @parts = ($parts[0]);
+		    $args->{'condensed'} = 1;
+		}
+            }
+        } 
+            
+        # If the multipart problem was condensed, "forget" it was multipart
+        if (scalar(@parts) == 1) {
+            $args->{'multipart'} = 0;
+        } else {
+            # Add part 0 so we display it correctly.
+            unshift @parts, '0';
+        }
+
+        # Now, we've decided what parts to show. Loop through them and
+        # show them.
+        foreach my $part (@parts) {
+            $rownum ++;
+            my $backgroundColor = $backgroundColors[$rownum % scalar(@backgroundColors)];
+            
+            $result .= "  <tr bgcolor='$backgroundColor'>\n";
+
+            # Set up some data about the parts that the cols might want
+            my $filter = $it->{FILTER};
+            my $stack = $it->getStack();
+            my $src = getLinkForResource($stack);
+            
+            my $srcHasQuestion = $src =~ /\?/;
+            $args->{"resourceLink"} = $src.
+                ($srcHasQuestion?'&':'?') .
+                'symb=' . &Apache::lonnet::escape($curRes->symb());
+            
+            # Now, display each column.
+            foreach my $col (@$cols) {
+                my $colHTML = '';
+                if (ref($col)) {
+                    $colHTML .= &$col($curRes, $part, $args);
+                } else {
+                    $colHTML .= &{$preparedColumns[$col]}($curRes, $part, $args);
+                }
+
+                # If this is the first column and it's time to print
+                # the anchor, do so
+                if ($col == $cols->[0] && 
+                    $args->{'counter'} == $args->{'currentJumpIndex'} - 
+                    $currentJumpDelta) {
+                    # Jam the anchor after the <td> tag;
+                    # necessary for valid HTML (which Mozilla requires)
+                    $colHTML =~ s/\>/\>\<a name="curloc" \/\>/;
+                    $displayedJumpMarker = 1;
+                }
+                $result .= $colHTML . "\n";
+            }
+            $result .= "    </tr>\n";
+            $args->{'isNewBranch'} = 0;
+        }
+
+        if ($r && $rownum % 20 == 0) {
+            $r->print($result);
+            $result = "";
+            $r->rflush();
+        }
+    } continue {
+        $curRes = $it->next();
+
+	if ($r) {
+	    # If we have the connection, make sure the user is still connected
+	    my $c = $r->connection;
+	    if ($c->aborted()) {
+		Apache::lonnet::logthis("navmaps aborted");
+		# Who cares what we do, nobody will see it anyhow.
+		return '';
+	    }
+	}
+    }
+    
+    # Print out the part that jumps to #curloc if it exists
+    # delay needed because the browser is processing the jump before
+    # it finishes rendering, so it goes to the wrong place!
+    # onload might be better, but this routine has no access to that.
+    # On mozilla, the 0-millisecond timeout seems to prevent this;
+    # it's quite likely this might fix other browsers, too, and 
+    # certainly won't hurt anything.
+    if ($displayedJumpMarker) {
+        $result .= "<script>setTimeout(\"location += '#curloc';\", 0)</script>\n";
+    }
+
+    $result .= "</table>";
+    
+    if ($r) {
+        $r->print($result);
+        $result = "";
+        $r->rflush();
+    }
+        
+    if ($mustCloseNavMap) { $navmap->untieHashes(); } 
+
+    return $result;
+}
+
+1;
+
+package Apache::lonnavmaps::navmap;
+
+=pod
+
+=head1 Object: Apache::lonnavmaps::navmap
+
+=head2 Overview
+
+The navmap object's job is to provide access to the resources
+in the course as Apache::lonnavmaps::resource objects, and to
+query and manage the relationship between those resource objects.
+
+Generally, you'll use the navmap object in one of three basic ways.
+In order of increasing complexity and power:
+
+=over 4
+
+=item * C<$navmap-E<gt>getByX>, where X is B<Id>, B<Symb>, B<Url> or B<MapPc>. This provides
+    various ways to obtain resource objects, based on various identifiers.
+    Use this when you want to request information about one object or 
+    a handful of resources you already know the identities of, from some
+    other source. For more about Ids, Symbs, and MapPcs, see the
+    Resource documentation. Note that Url should be a B<last resort>,
+    not your first choice; it only works when there is only one
+    instance of the resource in the course, which only applies to
+    maps, and even that may change in the future.
+
+=item * C<my @resources = $navmap-E<gt>retrieveResources(args)>. This
+    retrieves resources matching some criterion and returns them
+    in a flat array, with no structure information. Use this when
+    you are manipulating a series of resources, based on what map
+    the are in, but do not care about branching, or exactly how
+    the maps and resources are related. This is the most common case.
+
+=item * C<$it = $navmap-E<gt>getIterator(args)>. This allows you traverse
+    the course's navmap in various ways without writing the traversal
+    code yourself. See iterator documentation below. Use this when
+    you need to know absolutely everything about the course, including
+    branches and the precise relationship between maps and resources.
+
+=back
+
+=head2 Creation And Destruction
+
+To create a navmap object, use the following function:
+
+=over 4
+
+=item * B<Apache::lonnavmaps::navmap-E<gt>new>(navHashFile, parmHashFile, 
+  genCourseAndUserOptions, genMailDiscussStatus, getUserData):
+
+Binds a new navmap object to the compiled nav map hash and parm hash
+given as filenames. genCourseAndUserOptions is a flag saying whether
+the course options and user options hash should be generated. This is
+for when you are using the parameters of the resources that require
+them; see documentation in resource object
+documentation. genMailDiscussStatus causes the nav map to retreive
+information about the email and discussion status of
+resources. Returns the navmap object if this is successful, or
+B<undef> if not. You must check for undef; errors will occur when you
+try to use the other methods otherwise. getUserData, if true, will 
+retreive the user's performance data for various problems.
+
+=back
+
+Once you have the $navmap object, call ->init() on it when you are ready
+to use it. This allows you to check if the course map is defined (see
+B<courseMapDefined> below) before engaging in potentially expensive 
+initialization routines for the genCourseAndUserOptions and 
+genMailDiscussStatus option.
+
+When you are done with the $navmap object, you I<must> call 
+$navmap->untieHashes(), or you'll prevent the current user from using that 
+course until the web server is restarted. (!)
+
+=head2 Methods
+
+=over 4
+
+=item * B<getIterator>(first, finish, filter, condition):
+
+See iterator documentation below.
+
+=cut
+
+use strict;
 use GDBM_File;
 
-# -------------------------------------------------------------- Module Globals
-my %hash;
-my @rows;
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    $self->{NAV_HASH_FILE} = shift;
+    $self->{PARM_HASH_FILE} = shift;
+    $self->{GENERATE_COURSE_USER_OPT} = shift;
+    $self->{GENERATE_EMAIL_DISCUSS_STATUS} = shift;
+    $self->{GET_USER_DATA} = shift;
+
+    # Resource cache stores navmap resources as we reference them. We generate
+    # them on-demand so we don't pay for creating resources unless we use them.
+    $self->{RESOURCE_CACHE} = {};
+
+    # Network failure flag, if we accessed the course or user opt and
+    # failed
+    $self->{NETWORK_FAILURE} = 0;
+
+    # tie the nav hash
+
+    my %navmaphash;
+    my %parmhash;
+    if (!(tie(%navmaphash, 'GDBM_File', $self->{NAV_HASH_FILE},
+              &GDBM_READER(), 0640))) {
+        return undef;
+    }
+    
+    if (!(tie(%parmhash, 'GDBM_File', $self->{PARM_HASH_FILE},
+              &GDBM_READER(), 0640)))
+    {
+        untie %{$self->{PARM_HASH}};
+        return undef;
+    }
 
-#
-# These cache hashes need to be independent of user, resource and course
-# (user and course can/should be in the keys)
-#
+    $self->{NAV_HASH} = \%navmaphash;
+    $self->{PARM_HASH} = \%parmhash;
+    $self->{INITED} = 0;
+
+    bless($self);
+        
+    return $self;
+}
 
-my %courserdatas;
-my %userrdatas;
+sub init {
+    my $self = shift;
+    if ($self->{INITED}) { return; }
+
+    # If the course opt hash and the user opt hash should be generated,
+    # generate them
+    if ($self->{GENERATE_COURSE_USER_OPT}) {
+        my $uname=$ENV{'user.name'};
+        my $udom=$ENV{'user.domain'};
+        my $uhome=$ENV{'user.home'};
+        my $cid=$ENV{'request.course.id'};
+        my $chome=$ENV{'course.'.$cid.'.home'};
+        my ($cdom,$cnum)=split(/\_/,$cid);
+        
+        my $userprefix=$uname.'_'.$udom.'_';
+        
+        my %courserdatas; my %useropt; my %courseopt; my %userrdatas;
+        unless ($uhome eq 'no_host') { 
+# ------------------------------------------------- Get coursedata (if present)
+            unless ((time-$courserdatas{$cid.'.last_cache'})<240) {
+                my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
+                                                 ':resourcedata',$chome);
+                # Check for network failure
+                if ( $reply =~ /no.such.host/i || $reply =~ /con_lost/i) {
+                    $self->{NETWORK_FAILURE} = 1;
+                } elsif ($reply!~/^error\:/) {
+                    $courserdatas{$cid}=$reply;
+                    $courserdatas{$cid.'.last_cache'}=time;
+                }
+            }
+            foreach (split(/\&/,$courserdatas{$cid})) {
+                my ($name,$value)=split(/\=/,$_);
+                $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
+                    &Apache::lonnet::unescape($value);
+            }
+# --------------------------------------------------- Get userdata (if present)
+            unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
+                my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
+                if ($reply!~/^error\:/) {
+                    $userrdatas{$uname.'___'.$udom}=$reply;
+                    $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
+                }
+                # check to see if network failed
+                elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
+                {
+                    $self->{NETWORK_FAILURE} = 1;
+                }
+            }
+            foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) {
+                my ($name,$value)=split(/\=/,$_);
+                $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
+                    &Apache::lonnet::unescape($value);
+            }
+            $self->{COURSE_OPT} = \%courseopt;
+            $self->{USER_OPT} = \%useropt;
+        }
+    }   
 
-#
-# These global hashes are dependent on user, course and resource, 
-# and need to be initialized every time when a sheet is calculated
-#
-my %courseopt;
-my %useropt;
-my %parmhash;
+    if ($self->{GENERATE_EMAIL_DISCUSS_STATUS}) {
+        my $cid=$ENV{'request.course.id'};
+        my ($cdom,$cnum)=split(/\_/,$cid);
+        
+        my %emailstatus = &Apache::lonnet::dump('email_status');
+        my $logoutTime = $emailstatus{'logout'};
+        my $courseLeaveTime = $emailstatus{'logout_'.$ENV{'request.course.id'}};
+        $self->{LAST_CHECK} = (($courseLeaveTime > $logoutTime) ?
+                               $courseLeaveTime : $logoutTime);
+        my %discussiontime = &Apache::lonnet::dump('discussiontimes', 
+                                                   $cdom, $cnum);
+        my %feedback=();
+        my %error=();
+        my $keys = &Apache::lonnet::reply('keys:'.
+                                          $ENV{'user.domain'}.':'.
+                                          $ENV{'user.name'}.':nohist_email',
+                                          $ENV{'user.home'});
+
+        foreach my $msgid (split(/\&/, $keys)) {
+            $msgid=&Apache::lonnet::unescape($msgid);
+            my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
+            if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) {
+                my ($what,$url)=($1,$2);
+                my %status=
+                    &Apache::lonnet::get('email_status',[$msgid]);
+                if ($status{$msgid}=~/^error\:/) { 
+                    $status{$msgid}=''; 
+                }
+                
+                if (($status{$msgid} eq 'new') || 
+                    (!$status{$msgid})) { 
+                    if ($what eq 'Error') {
+                        $error{$url}.=','.$msgid; 
+                    } else {
+                        $feedback{$url}.=','.$msgid;
+                    }
+                }
+            }
+        }
+        
+        $self->{FEEDBACK} = \%feedback;
+        $self->{ERROR_MSG} = \%error; # what is this? JB
+        $self->{DISCUSSION_TIME} = \%discussiontime;
+        $self->{EMAIL_STATUS} = \%emailstatus;
+        
+    }
 
+    if ($self->{GET_USER_DATA}) {
+	# Retreive performance data on problems
+	my %student_data = Apache::lonnet::currentdump($ENV{'request.course.id'},
+						       $ENV{'user.domain'},
+						       $ENV{'user.name'});
+	$self->{STUDENT_DATA} = \%student_data;
+    }
+
+    $self->{PARM_CACHE} = {};
+    $self->{INITED} = 1;
+}
+
+# Internal function: Takes a key to look up in the nav hash and implements internal
+# memory caching of that key.
+sub navhash {
+    my $self = shift; my $key = shift;
+    return $self->{NAV_HASH}->{$key};
+}
+
+=pod
+
+=item * B<courseMapDefined>(): Returns true if the course map is defined, 
+    false otherwise. Undefined course maps indicate an error somewhere in
+    LON-CAPA, and you will not be able to proceed with using the navmap.
+    See the B<NAV> screen for an example of using this.
+
+=cut
+
+# Checks to see if coursemap is defined, matching test in old lonnavmaps
+sub courseMapDefined {
+    my $self = shift;
+    my $uri = &Apache::lonnet::clutter($ENV{'request.course.uri'});
+
+    my $firstres = $self->navhash("map_start_$uri");
+    my $lastres = $self->navhash("map_finish_$uri");
+    return $firstres && $lastres;
+}
 
-# ------------------------------------------------------------------ Euclid gcd
+sub getIterator {
+    my $self = shift;
+    my $iterator = Apache::lonnavmaps::iterator->new($self, shift, shift,
+                                                     shift, undef, shift);
+    return $iterator;
+}
+
+# unties the hash when done
+sub untieHashes {
+    my $self = shift;
+    untie %{$self->{NAV_HASH}};
+    untie %{$self->{PARM_HASH}};
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current discussion? Returns 0 if chat/mail data not extracted.
+sub hasDiscussion {
+    my $self = shift;
+    my $symb = shift;
+    if (!defined($self->{DISCUSSION_TIME})) { return 0; }
+
+    #return defined($self->{DISCUSSION_TIME}->{$symb});
+    return $self->{DISCUSSION_TIME}->{$symb} >
+           $self->{LAST_CHECK};
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current feedback? Returns the string in the feedback hash, which
+# will be false if it does not exist.
+sub getFeedback { 
+    my $self = shift;
+    my $symb = shift;
+
+    if (!defined($self->{FEEDBACK})) { return ""; }
+    
+    return $self->{FEEDBACK}->{$symb};
+}
 
-sub euclid {
-    my ($e,$f)=@_;
-    my $a; my $b; my $r;
-    if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; }
-    while ($r!=0) {
-	$a=$b; $b=$r;
-        $r=$a%$b;
+# Private method: Get the errors for that resource (by source).
+sub getErrors { 
+    my $self = shift;
+    my $src = shift;
+    
+    if (!defined($self->{ERROR_MSG})) { return ""; }
+    return $self->{ERROR_MSG}->{$src};
+}
+
+=pod
+
+=item * B<getById>(id):
+
+Based on the ID of the resource (1.1, 3.2, etc.), get a resource
+object for that resource. This method, or other methods that use it
+(as in the resource object) is the only proper way to obtain a
+resource object.
+
+=item * B<getBySymb>(symb):
+
+Based on the symb of the resource, get a resource object for that
+resource. This is one of the proper ways to get a resource object.
+
+=item * B<getMapByMapPc>(map_pc):
+
+Based on the map_pc of the resource, get a resource object for
+the given map. This is one of the proper ways to get a resource object.
+
+=cut
+
+# The strategy here is to cache the resource objects, and only construct them
+# as we use them. The real point is to prevent reading any more from the tied
+# hash then we have to, which should hopefully alleviate speed problems.
+
+sub getById {
+    my $self = shift;
+    my $id = shift;
+
+    if (defined ($self->{RESOURCE_CACHE}->{$id}))
+    {
+        return $self->{RESOURCE_CACHE}->{$id};
     }
-    return $b;
+
+    # resource handles inserting itself into cache.
+    # Not clear why the quotes are necessary, but as of this
+    # writing it doesn't work without them.
+    return "Apache::lonnavmaps::resource"->new($self, $id);
 }
 
-# --------------------------------------------------------------------- Parmval
+sub getBySymb {
+    my $self = shift;
+    my $symb = shift;
+    my ($mapUrl, $id, $filename) = split (/___/, $symb);
+    my $map = $self->getResourceByUrl($mapUrl);
+    return $self->getById($map->map_pc() . '.' . $id);
+}
 
-# -------------------------------------------- Figure out a cascading parameter
-#
-# For this function to work
-#
-# * parmhash needs to be tied
-# * courseopt and useropt need to be initialized for this user and course
-#
+sub getByMapPc {
+    my $self = shift;
+    my $map_pc = shift;
+    my $map_id = $self->{NAV_HASH}->{'map_id_' . $map_pc};
+    $map_id = $self->{NAV_HASH}->{'ids_' . $map_id};
+    return $self->getById($map_id);
+}
+
+=pod
+
+=item * B<firstResource>():
+
+Returns a resource object reference corresponding to the first
+resource in the navmap.
+
+=cut
 
+sub firstResource {
+    my $self = shift;
+    my $firstResource = $self->navhash('map_start_' .
+                     &Apache::lonnet::clutter($ENV{'request.course.uri'}));
+    return $self->getById($firstResource);
+}
+
+=pod
+
+=item * B<finishResource>():
+
+Returns a resource object reference corresponding to the last resource
+in the navmap.
+
+=cut
+
+sub finishResource {
+    my $self = shift;
+    my $firstResource = $self->navhash('map_finish_' .
+                     &Apache::lonnet::clutter($ENV{'request.course.uri'}));
+    return $self->getById($firstResource);
+}
+
+# Parmval reads the parm hash and cascades the lookups. parmval_real does
+# the actual lookup; parmval caches the results.
 sub parmval {
+    my $self = shift;
     my ($what,$symb)=@_;
+    my $hashkey = $what."|||".$symb;
+
+    if (defined($self->{PARM_CACHE}->{$hashkey})) {
+        return $self->{PARM_CACHE}->{$hashkey};
+    }
+
+    my $result = $self->parmval_real($what, $symb);
+    $self->{PARM_CACHE}->{$hashkey} = $result;
+    return $result;
+}
+
+sub parmval_real {
+    my $self = shift;
+    my ($what,$symb,$recurse) = @_;
+
     my $cid=$ENV{'request.course.id'};
     my $csec=$ENV{'request.course.sec'};
     my $uname=$ENV{'user.name'};
@@ -77,509 +2040,2028 @@ sub parmval {
     my ($mapname,$id,$fn)=split(/\_\_\_/,$symb);
 
 # ----------------------------------------------------- Cascading lookup scheme
-       my $rwhat=$what;
-       $what=~s/^parameter\_//;
-       $what=~s/\_/\./;
-
-       my $symbparm=$symb.'.'.$what;
-       my $mapparm=$mapname.'___(all).'.$what;
-       my $usercourseprefix=$uname.'_'.$udom.'_'.$cid;
-
-       my $seclevel=
-            $usercourseprefix.'.['.
-		$csec.'].'.$what;
-       my $seclevelr=
-            $usercourseprefix.'.['.
-		$csec.'].'.$symbparm;
-       my $seclevelm=
-            $usercourseprefix.'.['.
-		$csec.'].'.$mapparm;
-
-       my $courselevel=
-            $usercourseprefix.'.'.$what;
-       my $courselevelr=
-            $usercourseprefix.'.'.$symbparm;
-       my $courselevelm=
-            $usercourseprefix.'.'.$mapparm;
-
-# ---------------------------------------------------------- fourth, check user
-      
-      if ($uname) { 
-
-       if ($useropt{$courselevelr}) { return $useropt{$courselevelr}; }
-
-       if ($useropt{$courselevelm}) { return $useropt{$courselevelm}; }
-
-       if ($useropt{$courselevel}) { return $useropt{$courselevel}; }
-
-      }
-
-# --------------------------------------------------------- third, check course
-     
-       if ($csec) {
- 
-        if ($courseopt{$seclevelr}) { return $courseopt{$seclevelr}; }
-
-        if ($courseopt{$seclevelm}) { return $courseopt{$seclevelm}; }  
-
-        if ($courseopt{$seclevel}) { return $courseopt{$seclevel}; }
-  
-      }
-
-       if ($courseopt{$courselevelr}) { return $courseopt{$courselevelr}; }
-
-       if ($courseopt{$courselevelm}) { return $courseopt{$courselevelm}; }
-
-       if ($courseopt{$courselevel}) { return $courseopt{$courselevel}; }
-
-# ----------------------------------------------------- second, check map parms
-
-       my $thisparm=$parmhash{$symbparm};
-       if ($thisparm) { return $thisparm; }
-
-# -------------------------------------------------------- first, check default
-
-       return &Apache::lonnet::metadata($fn,$rwhat.'.default');
+    my $rwhat=$what;
+    $what=~s/^parameter\_//;
+    $what=~s/\_/\./;
+
+    my $symbparm=$symb.'.'.$what;
+    my $mapparm=$mapname.'___(all).'.$what;
+    my $usercourseprefix=$uname.'_'.$udom.'_'.$cid;
+
+    my $seclevel= $usercourseprefix.'.['.$csec.'].'.$what;
+    my $seclevelr=$usercourseprefix.'.['.$csec.'].'.$symbparm;
+    my $seclevelm=$usercourseprefix.'.['.$csec.'].'.$mapparm;
+
+    my $courselevel= $usercourseprefix.'.'.$what;
+    my $courselevelr=$usercourseprefix.'.'.$symbparm;
+    my $courselevelm=$usercourseprefix.'.'.$mapparm;
+
+    my $useropt = $self->{USER_OPT};
+    my $courseopt = $self->{COURSE_OPT};
+    my $parmhash = $self->{PARM_HASH};
+
+# ---------------------------------------------------------- first, check user
+    if ($uname and defined($useropt)) {
+        if (defined($$useropt{$courselevelr})) { return $$useropt{$courselevelr}; }
+        if (defined($$useropt{$courselevelm})) { return $$useropt{$courselevelm}; }
+        if (defined($$useropt{$courselevel})) { return $$useropt{$courselevel}; }
+    }
+
+# ------------------------------------------------------- second, check course
+    if ($csec and defined($courseopt)) {
+        if (defined($$courseopt{$seclevelr})) { return $$courseopt{$seclevelr}; }
+        if (defined($$courseopt{$seclevelm})) { return $$courseopt{$seclevelm}; }
+        if (defined($$courseopt{$seclevel})) { return $$courseopt{$seclevel}; }
+    }
+
+    if (defined($courseopt)) {
+        if (defined($$courseopt{$courselevelr})) { return $$courseopt{$courselevelr}; }
+        if (defined($$courseopt{$courselevelm})) { return $$courseopt{$courselevelm}; }
+        if (defined($$courseopt{$courselevel})) { return $$courseopt{$courselevel}; }
+    }
+
+# ----------------------------------------------------- third, check map parms
+
+    my $thisparm=$$parmhash{$symbparm};
+    if (defined($thisparm)) { return $thisparm; }
+
+# ----------------------------------------------------- fourth , check default
+
+    my $default=&Apache::lonnet::metadata($fn,$rwhat.'.default');
+    if (defined($default)) { return $default}
+
+# --------------------------------------------------- fifth , cascade up parts
+
+    my ($space,@qualifier)=split(/\./,$rwhat);
+    my $qualifier=join('.',@qualifier);
+    unless ($space eq '0') {
+	my @parts=split(/_/,$space);
+	my $id=pop(@parts);
+	my $part=join('_',@parts);
+	if ($part eq '') { $part='0'; }
+	my $partgeneral=$self->parmval($part.".$qualifier",$symb,1);
+	if (defined($partgeneral)) { return $partgeneral; }
+    }
+    if ($recurse) { return undef; }
+    my $pack_def=&Apache::lonnet::packages_tab_default($fn,'resource.'.$what);
+    if (defined($pack_def)) { return $pack_def; }
+    return '';
+}
+
+=pod
+
+=item * B<getResourceByUrl>(url):
+
+Retrieves a resource object by URL of the resource. If passed a
+resource object, it will simply return it, so it is safe to use this
+method in code like "$res = $navmap->getResourceByUrl($res)", if
+you're not sure if $res is already an object, or just a URL. If the
+resource appears multiple times in the course, only the first instance
+will be returned. As a result, this is probably useful only for maps.
+
+=item * B<retrieveResources>(map, filterFunc, recursive, bailout):
+
+The map is a specification of a map to retreive the resources from,
+either as a url or as an object. The filterFunc is a reference to a
+function that takes a resource object as its one argument and returns
+true if the resource should be included, or false if it should not
+be. If recursive is true, the map will be recursively examined,
+otherwise it will not be. If bailout is true, the function will return
+as soon as it finds a resource, if false it will finish. By default,
+the map is the top-level map of the course, filterFunc is a function
+that always returns 1, recursive is true, bailout is false. The
+resources will be returned in a list containing the resource objects
+for the corresponding resources, with B<no structure information> in
+the list; regardless of branching, recursion, etc., it will be a flat
+list.
+
+Thus, this is suitable for cases where you don't want the structure,
+just a list of all resources. It is also suitable for finding out how
+many resources match a given description; for this use, if all you
+want to know is if I<any> resources match the description, the bailout
+parameter will allow you to avoid potentially expensive enumeration of
+all matching resources.
+
+=item * B<hasResources>(map, filterFunc, recursive):
+
+Convience method for
+
+ scalar(retrieveResources($map, $filterFunc, $recursive, 1)) > 0
+
+which will tell whether the map has resources matching the description
+in the filter function.
+
+=cut
+
+sub getResourceByUrl {
+    my $self = shift;
+    my $resUrl = shift;
+
+    if (ref($resUrl)) { return $resUrl; }
+
+    $resUrl = &Apache::lonnet::clutter($resUrl);
+    my $resId = $self->{NAV_HASH}->{'ids_' . $resUrl};
+    if ($resId =~ /,/) {
+        $resId = (split (/,/, $resId))[0];
+    }
+    if (!$resId) { return ''; }
+    return $self->getById($resId);
+}
+
+sub retrieveResources {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    if (!defined ($filterFunc)) {
+        $filterFunc = sub {return 1;};
+    }
+    my $recursive = shift;
+    if (!defined($recursive)) { $recursive = 1; }
+    my $bailout = shift;
+    if (!defined($bailout)) { $bailout = 0; }
+
+    # Create the necessary iterator.
+    if (!ref($map)) { # assume it's a url of a map.
+        $map = $self->getResourceByUrl($map);
+    }
+
+    # If nothing was passed, assume top-level map
+    if (!$map) {
+	$map = $self->getById('0.0');
+    }
+
+    # Check the map's validity.
+    if (!$map->is_map()) {
+        # Oh, to throw an exception.... how I'd love that!
+        return ();
+    }
+
+    # Get an iterator.
+    my $it = $self->getIterator($map->map_start(), $map->map_finish(),
+                                undef, $recursive);
+
+    my @resources = ();
+
+    # Run down the iterator and collect the resources.
+    my $depth = 1;
+    $it->next();
+    my $curRes = $it->next();
+
+    while ($depth > 0) {
+        if ($curRes == $it->BEGIN_MAP()) {
+            $depth++;
+        }
+        if ($curRes == $it->END_MAP()) {
+            $depth--;
+        }
+        
+        if (ref($curRes)) {
+            if (!&$filterFunc($curRes)) {
+                next;
+            }
+
+            push @resources, $curRes;
+
+            if ($bailout) {
+                return @resources;
+            }
+        }
+
+    } continue {
+        $curRes = $it->next();
+    }
+
+    return @resources;
+}
+
+sub hasResource {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    my $recursive = shift;
+    
+    return scalar($self->retrieveResources($map, $filterFunc, $recursive, 1)) > 0;
+}
+
+1;
+
+package Apache::lonnavmaps::iterator;
+
+=pod
+
+=back
+
+=head1 Object: navmap Iterator
+
+An I<iterator> encapsulates the logic required to traverse a data
+structure. navmap uses an iterator to traverse the course map
+according to the criteria you wish to use.
+
+To obtain an iterator, call the B<getIterator>() function of a
+B<navmap> object. (Do not instantiate Apache::lonnavmaps::iterator
+directly.) This will return a reference to the iterator:
+
+C<my $resourceIterator = $navmap-E<gt>getIterator();>
+
+To get the next thing from the iterator, call B<next>:
+
+C<my $nextThing = $resourceIterator-E<gt>next()>
+
+getIterator behaves as follows:
+
+=over 4
+
+=item * B<getIterator>(firstResource, finishResource, filterHash, condition, forceTop, returnTopMap):
+
+All parameters are optional. firstResource is a resource reference
+corresponding to where the iterator should start. It defaults to
+navmap->firstResource() for the corresponding nav map. finishResource
+corresponds to where you want the iterator to end, defaulting to
+navmap->finishResource(). filterHash is a hash used as a set
+containing strings representing the resource IDs, defaulting to
+empty. Condition is a 1 or 0 that sets what to do with the filter
+hash: If a 0, then only resources that exist IN the filterHash will be
+recursed on. If it is a 1, only resources NOT in the filterHash will
+be recursed on. Defaults to 0. forceTop is a boolean value. If it is
+false (default), the iterator will only return the first level of map
+that is not just a single, 'redirecting' map. If true, the iterator
+will return all information, starting with the top-level map,
+regardless of content. returnTopMap, if true (default false), will
+cause the iterator to return the top-level map object (resource 0.0)
+before anything else.
+
+Thus, by default, only top-level resources will be shown. Change the
+condition to a 1 without changing the hash, and all resources will be
+shown. Changing the condition to 1 and including some values in the
+hash will allow you to selectively suppress parts of the navmap, while
+leaving it on 0 and adding things to the hash will allow you to
+selectively add parts of the nav map. See the handler code for
+examples.
+
+The iterator will return either a reference to a resource object, or a
+token representing something in the map, such as the beginning of a
+new branch. The possible tokens are:
+
+=over 4
+
+=item * B<BEGIN_MAP>:
+
+A new map is being recursed into. This is returned I<after> the map
+resource itself is returned.
+
+=item * B<END_MAP>:
+
+The map is now done.
+
+=item * B<BEGIN_BRANCH>:
+
+A branch is now starting. The next resource returned will be the first
+in that branch.
+
+=item * B<END_BRANCH>:
+
+The branch is now done.
+
+=back
+
+The tokens are retreivable via methods on the iterator object, i.e.,
+$iterator->END_MAP.
+
+Maps can contain empty resources. The iterator will automatically skip
+over such resources, but will still treat the structure
+correctly. Thus, a complicated map with several branches, but
+consisting entirely of empty resources except for one beginning or
+ending resource, will cause a lot of BRANCH_STARTs and BRANCH_ENDs,
+but only one resource will be returned.
+
+=back
+
+=cut
+
+# Here are the tokens for the iterator:
+
+sub BEGIN_MAP { return 1; }    # begining of a new map
+sub END_MAP { return 2; }      # end of the map
+sub BEGIN_BRANCH { return 3; } # beginning of a branch
+sub END_BRANCH { return 4; }   # end of a branch
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
+
+sub min {
+    (my $a, my $b) = @_;
+    if ($a < $b) { return $a; } else { return $b; }
+}
+
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    $self->{NAV_MAP} = shift;
+    return undef unless ($self->{NAV_MAP});
+
+    # Handle the parameters
+    $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource();
+    $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource();
+
+    # If the given resources are just the ID of the resource, get the
+    # objects
+    if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); }
+    if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); }
+
+    $self->{FILTER} = shift;
+
+    # A hash, used as a set, of resource already seen
+    $self->{ALREADY_SEEN} = shift;
+    if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
+
+    # Do we want to automatically follow "redirection" maps?
+    $self->{FORCE_TOP} = shift;
+
+    # Do we want to return the top-level map object (resource 0.0)?
+    $self->{RETURN_0} = shift;
+    # have we done that yet?
+    $self->{HAVE_RETURNED_0} = 0;
+
+    # Now, we need to pre-process the map, by walking forward and backward
+    # over the parts of the map we're going to look at.
+
+    # The processing steps are exactly the same, except for a few small 
+    # changes, so I bundle those up in the following list of two elements:
+    # (direction_to_iterate, VAL_name, next_resource_method_to_call,
+    # first_resource).
+    # This prevents writing nearly-identical code twice.
+    my @iterations = ( [FORWARD(), 'TOP_DOWN_VAL', 'getNext', 
+                        'FIRST_RESOURCE'],
+                       [BACKWARD(), 'BOT_UP_VAL', 'getPrevious', 
+                        'FINISH_RESOURCE'] );
+
+    my $maxDepth = 0; # tracks max depth
+
+    # If there is only one resource in this map, and it's a map, we
+    # want to remember that, so the user can ask for the first map
+    # that isn't just a redirector.
+    my $resource; my $resourceCount = 0;
+
+    # Documentation on this algorithm can be found in the CVS repository at 
+    # /docs/lonnavdocs; these "**#**" markers correspond to documentation
+    # in that file.
+    # **1**
+
+    foreach my $pass (@iterations) {
+        my $direction = $pass->[0];
+        my $valName = $pass->[1];
+        my $nextResourceMethod = $pass->[2];
+        my $firstResourceName = $pass->[3];
+
+        my $iterator = Apache::lonnavmaps::DFSiterator->new($self->{NAV_MAP}, 
+                                                            $self->{FIRST_RESOURCE},
+                                                            $self->{FINISH_RESOURCE},
+                                                            {}, undef, 0, $direction);
+    
+        # prime the recursion
+        $self->{$firstResourceName}->{DATA}->{$valName} = 0;
+        my $depth = 0;
+        $iterator->next();
+        my $curRes = $iterator->next();
+        while ($depth > -1) {
+            if ($curRes == $iterator->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $iterator->END_MAP()) { $depth--; }
+        
+            if (ref($curRes)) {
+                # If there's only one resource, this will save it
+                # we have to filter empty resources from consideration here,
+                # or even "empty", redirecting maps have two (start & finish)
+                # or three (start, finish, plus redirector)
+                if($direction == FORWARD && $curRes->src()) { 
+                    $resource = $curRes; $resourceCount++; 
+                }
+                my $resultingVal = $curRes->{DATA}->{$valName};
+                my $nextResources = $curRes->$nextResourceMethod();
+                my $nextCount = scalar(@{$nextResources});
+
+                if ($nextCount == 1) { # **3**
+                    my $current = $nextResources->[0]->{DATA}->{$valName} || 999999999;
+                    $nextResources->[0]->{DATA}->{$valName} = min($resultingVal, $current);
+                }
+                
+                if ($nextCount > 1) { # **4**
+                    foreach my $res (@{$nextResources}) {
+                        my $current = $res->{DATA}->{$valName} || 999999999;
+                        $res->{DATA}->{$valName} = min($current, $resultingVal + 1);
+                    }
+                }
+            }
+            
+            # Assign the final val (**2**)
+            if (ref($curRes) && $direction == BACKWARD()) {
+                my $finalDepth = min($curRes->{DATA}->{TOP_DOWN_VAL},
+                                     $curRes->{DATA}->{BOT_UP_VAL});
+                
+                $curRes->{DATA}->{DISPLAY_DEPTH} = $finalDepth;
+                if ($finalDepth > $maxDepth) {$maxDepth = $finalDepth;}
+            }
+        } continue {
+            $curRes = $iterator->next();
+        }
+    }
+
+    # Check: Was this only one resource, a map?
+    if ($resourceCount == 1 && $resource->is_map() && !$self->{FORCE_TOP}) { 
+        my $firstResource = $resource->map_start();
+        my $finishResource = $resource->map_finish();
+        return 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN}, 
+                                              $self->{CONDITION}, 0);
         
+    }
+
+    # Set up some bookkeeping information.
+    $self->{CURRENT_DEPTH} = 0;
+    $self->{MAX_DEPTH} = $maxDepth;
+    $self->{STACK} = [];
+    $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+
+    for (my $i = 0; $i <= $self->{MAX_DEPTH}; $i++) {
+        push @{$self->{STACK}}, [];
+    }
+
+    # Prime the recursion w/ the first resource **5**
+    push @{$self->{STACK}->[0]}, $self->{FIRST_RESOURCE};
+    $self->{ALREADY_SEEN}->{$self->{FIRST_RESOURCE}->{ID}} = 1;
+
+    bless ($self);
+
+    return $self;
+}
+
+sub next {
+    my $self = shift;
+
+    # If we want to return the top-level map object, and haven't yet,
+    # do so.
+    if ($self->{RETURN_0} && !$self->{HAVE_RETURNED_0}) {
+        $self->{HAVE_RETURNED_0} = 1;
+        return $self->{NAV_MAP}->getById('0.0');
+    }
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        # grab the next from the recursive iterator 
+        my $next = $self->{RECURSIVE_ITERATOR}->next();
+
+        # is it a begin or end map? If so, update the depth
+        if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; }
+        if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; }
+
+        # Are we back at depth 0? If so, stop recursing
+        if ($self->{RECURSIVE_DEPTH} == 0) {
+            $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+        }
+
+        return $next;
+    }
+
+    if (defined($self->{FORCE_NEXT})) {
+        my $tmp = $self->{FORCE_NEXT};
+        $self->{FORCE_NEXT} = undef;
+        return $tmp;
+    }
+
+    # Have we not yet begun? If not, return BEGIN_MAP and
+    # remember we've started.
+    if ( !$self->{STARTED} ) { 
+        $self->{STARTED} = 1;
+        return $self->BEGIN_MAP();
+    }
+
+    # Here's the guts of the iterator.
+    
+    # Find the next resource, if any.
+    my $found = 0;
+    my $i = $self->{MAX_DEPTH};
+    my $newDepth;
+    my $here;
+    while ( $i >= 0 && !$found ) {
+        if ( scalar(@{$self->{STACK}->[$i]}) > 0 ) { # **6**
+            $here = pop @{$self->{STACK}->[$i]}; # **7**
+            $found = 1;
+            $newDepth = $i;
+        }
+        $i--;
+    }
+
+    # If we still didn't find anything, we're done.
+    if ( !$found ) {
+        # We need to get back down to the correct branch depth
+        if ( $self->{CURRENT_DEPTH} > 0 ) {
+            $self->{CURRENT_DEPTH}--;
+            return END_BRANCH();
+        } else {
+            return END_MAP();
+        }
+    }
+
+    # If this is not a resource, it must be an END_BRANCH marker we want
+    # to return directly.
+    if (!ref($here)) { # **8**
+        if ($here == END_BRANCH()) { # paranoia, in case of later extension
+            $self->{CURRENT_DEPTH}--;
+            return $here;
+        }
+    }
+
+    # Otherwise, it is a resource and it's safe to store in $self->{HERE}
+    $self->{HERE} = $here;
+
+    # Get to the right level
+    if ( $self->{CURRENT_DEPTH} > $newDepth ) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}--;
+        return END_BRANCH();
+    }
+    if ( $self->{CURRENT_DEPTH} < $newDepth) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}++;
+        return BEGIN_BRANCH();
+    }
+
+    # If we made it here, we have the next resource, and we're at the
+    # right branch level. So let's examine the resource for where
+    # we can get to from here.
+
+    # So we need to look at all the resources we can get to from here,
+    # categorize them if we haven't seen them, remember if we have a new
+    my $nextUnfiltered = $here->getNext();
+    my $maxDepthAdded = -1;
+    
+    for (@$nextUnfiltered) {
+        if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
+            my $depth = $_->{DATA}->{DISPLAY_DEPTH};
+            push @{$self->{STACK}->[$depth]}, $_;
+            $self->{ALREADY_SEEN}->{$_->{ID}} = 1;
+            if ($maxDepthAdded < $depth) { $maxDepthAdded = $depth; }
+        }
+    }
+
+    # Is this the end of a branch? If so, all of the resources examined above
+    # led to lower levels then the one we are currently at, so we push a END_BRANCH
+    # marker onto the stack so we don't forget.
+    # Example: For the usual A(BC)(DE)F case, when the iterator goes down the
+    # BC branch and gets to C, it will see F as the only next resource, but it's
+    # one level lower. Thus, this is the end of the branch, since there are no
+    # more resources added to this level or above.
+    # We don't do this if the examined resource is the finish resource,
+    # because the condition given above is true, but the "END_MAP" will
+    # take care of things and we should already be at depth 0.
+    my $isEndOfBranch = $maxDepthAdded < $self->{CURRENT_DEPTH};
+    if ($isEndOfBranch && $here != $self->{FINISH_RESOURCE}) { # **9**
+        push @{$self->{STACK}->[$self->{CURRENT_DEPTH}]}, END_BRANCH();
+    }
+
+    # That ends the main iterator logic. Now, do we want to recurse
+    # down this map (if this resource is a map)?
+    if ($self->{HERE}->is_map() &&
+        (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) {
+        $self->{RECURSIVE_ITERATOR_FLAG} = 1;
+        my $firstResource = $self->{HERE}->map_start();
+        my $finishResource = $self->{HERE}->map_finish();
+
+        $self->{RECURSIVE_ITERATOR} = 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN}, $self->{CONDITION});
+    }
+
+    # If this is a blank resource, don't actually return it.
+    # Should you ever find you need it, make sure to add an option to the code
+    #  that you can use; other things depend on this behavior.
+    my $browsePriv = $self->{HERE}->browsePriv();
+    if (!$self->{HERE}->src() || 
+        (!($browsePriv eq 'F') && !($browsePriv eq '2')) ) {
+        return $self->next();
+    }
+
+    return $self->{HERE};
+
 }
 
+=pod
+
+The other method available on the iterator is B<getStack>, which
+returns an array populated with the current 'stack' of maps, as
+references to the resource objects. Example: This is useful when
+making the navigation map, as we need to check whether we are under a
+page map to see if we need to link directly to the resource, or to the
+page. The first elements in the array will correspond to the top of
+the stack (most inclusive map).
 
+=cut
 
-# ------------------------------------------------------------- Find out status
-
-sub astatus {
-    my $rid=shift;
-    my $code=1;
-    my $ctext='';
-    $rid=~/(\d+)\.(\d+)/;
-    my $symb=&Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'.
-	     &Apache::lonnet::declutter($hash{'src_'.$rid});
-
-    my %duedate=();
-    my %opendate=();
-    my %answerdate=();
-    map {
-        if ($_=~/^parameter\_(.*)\_opendate$/) {
-	    my $part=$1;
-            $duedate{$part}=&parmval($part.'.duedate',$symb);
-            $opendate{$part}=&parmval($part.'.opendate',$symb);
-            $answerdate{$part}=&parmval($part.'.answerdate',$symb);
-        }
-    } sort split(/\,/,&Apache::lonnet::metadata($hash{'src_'.$rid},'keys'));
-
-    my $now=time;
-    my $tcode=0;
-
-    my %returnhash=&Apache::lonnet::restore($symb);
-
-  map {
-
-   my $duedate=$duedate{$_};
-   my $opendate=$opendate{$_};
-   my $answerdate=$answerdate{$_};
-   my $preface='';
-   unless ($_ eq '0') { $preface=' Part: '.$_.' '; }
-   if ($opendate) {
-    if ($now<$duedate) {
-        unless ($tcode==4) { $tcode=2; } 
-        $ctext.=$preface.'Due: '.localtime($duedate);
-        if ($now<$opendate) { 
-          unless ($tcode) { $tcode=1; } 
-          $ctext.=$preface.'Open: '.localtime($opendate);
-        }
-        if ($duedate-$now<86400) {
-	   $tcode=4;
-           $ctext.=$preface.'Due: '.localtime($duedate);
-        }
-     } else {
-	 unless (($tcode==4) || ($tcode eq 2)) { $tcode=3; }
-       if ($now<$answerdate) {  
-          $ctext.='Answer: '.localtime($duedate);
-       }
-    }
-   } else {
-       unless (($tcode==2) || ($tcode==4)) { $tcode=1; }
-   }
-
-    my $status=$returnhash{'resource.'.$_.'.solved'};
-
-	       if ($status eq 'correct_by_student') {
-                   unless ($code==2) { $code=3; }
-                   $ctext.=' solved';
-               } elsif ($status eq 'correct_by_override') {
-                   unless ($code==2) { $code=3; }
-                   $ctext.=' override';
-               } elsif ($status eq 'incorrect_attempted') {
-                   $code=2;
-                   $ctext.=' ('.
-                     ($returnhash{'resource.'.$_.'.tries'}?
-                      $returnhash{'resource.'.$_.'.tries'}:'0').'/'.
-                     &parmval($_.'.maxtries',$symb).' tries)';
-               } elsif ($status eq 'incorrect_by_override') {
-                   $code=2;
-                   $ctext.=' override';
-               } elsif ($status eq 'excused') {
-                   unless ($code==2) { $code=3; }
-                   $ctext.=' excused';
-               }
-
-   } sort keys %opendate;
-
-    return 'p'.$code.$tcode.'"'.$ctext.'"';
-}
-
-# ------------------------------------------------------------ Build page table
-
-sub tracetable {
-    my ($sofar,$rid,$beenhere)=@_;
-    my $further=$sofar;
-    unless ($beenhere=~/\&$rid\&/) {
-       $beenhere.=$rid.'&';  
-
-       if (defined($hash{'is_map_'.$rid})) {
-           $sofar++;
-           my $tprefix='';
-           if ($hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}} 
-            eq 'sequence') { 
-               $tprefix='h'; 
-           }
-           if (defined($rows[$sofar])) {
-              $rows[$sofar].='&'.$tprefix.$rid;
-           } else {
-              $rows[$sofar]=$tprefix.$rid;
-           }
-           if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
-               (defined($hash{'map_finish_'.$hash{'src_'.$rid}})) &&
-               ($tprefix eq 'h')) {
-              my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
-	      $sofar=
-                &tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},
-                '&'.$frid.'&');
-              $sofar++;
-              if ($hash{'src_'.$frid}) {
-               my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$frid});
-               if (($brepriv eq '2') || ($brepriv eq 'F')) {
-		 my $pprefix='';
-                 if ($hash{'src_'.$frid}=~
-                                 /\.(problem|exam|quiz|assess|survey|form)$/) {
-		     $pprefix=&astatus($frid);
-
-                 }
-                 if (defined($rows[$sofar])) {
-                   $rows[$sofar].='&'.$pprefix.$frid;
-                 } else {
-                   $rows[$sofar]=$pprefix.$frid;
-                 }
-	       }
-	      }
-	   }
-       } else {
-          $sofar++;
-          if ($hash{'src_'.$rid}) {
-           my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$rid});
-           if (($brepriv eq '2') || ($brepriv eq 'F')) {
-	     my $pprefix='';
-             if ($hash{'src_'.$rid}=~
-                                 /\.(problem|exam|quiz|assess|survey|form)$/) {
-	         $pprefix=&astatus($rid);
-             }
-             if (defined($rows[$sofar])) {
-                $rows[$sofar].='&'.$pprefix.$rid;
-             } else {
-               $rows[$sofar]=$pprefix.$rid;
-             }
-	   }
-          }
-       }
-
-       if (defined($hash{'to_'.$rid})) {
-	  my $mincond=1;
-          my $next='';
-          map {
-              my $thiscond=
-      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
-              if ($thiscond>=$mincond) {
-		  if ($next) {
-		      $next.=','.$_.':'.$thiscond;
-                  } else {
-                      $next=$_.':'.$thiscond;
-		  }
-                  if ($thiscond>$mincond) { $mincond=$thiscond; }
-	      }
-          } split(/\,/,$hash{'to_'.$rid});
-          map {
-              my ($linkid,$condval)=split(/\:/,$_);
-              if ($condval>=$mincond) {
-                my $now=&tracetable($sofar,$hash{'goesto_'.$linkid},$beenhere);
-                if ($now>$further) { $further=$now; }
-	      }
-          } split(/\,/,$next);
+sub getStack {
+    my $self=shift;
 
-       }
+    my @stack;
+
+    $self->populateStack(\@stack);
+
+    return \@stack;
+}
+
+# Private method: Calls the iterators recursively to populate the stack.
+sub populateStack {
+    my $self=shift;
+    my $stack = shift;
+
+    push @$stack, $self->{HERE} if ($self->{HERE});
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        $self->{RECURSIVE_ITERATOR}->populateStack($stack);
     }
-    return $further;
 }
 
-# ================================================================ Main Handler
+1;
 
-sub handler {
-  my $r=shift;
+package Apache::lonnavmaps::DFSiterator;
 
+# Not documented in the perldoc: This is a simple iterator that just walks
+#  through the nav map and presents the resources in a depth-first search
+#  fashion, ignorant of conditionals, randomized resources, etc. It presents
+#  BEGIN_MAP and END_MAP, but does not understand branches at all. It is
+#  useful for pre-processing of some kind, and is in fact used by the main
+#  iterator that way, but that's about it.
+# One could imagine merging this into the init routine of the main iterator,
+#  but this might as well be left seperate, since it is possible some other
+#  use might be found for it. - Jeremy
+
+# Unlike the main iterator, this DOES return all resources, even blank ones.
+#  The main iterator needs them to correctly preprocess the map.
+
+sub BEGIN_MAP { return 1; }    # begining of a new map
+sub END_MAP { return 2; }      # end of the map
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
+
+# Params: Nav map ref, first resource id/ref, finish resource id/ref,
+#         filter hash ref (or undef), already seen hash or undef, condition
+#         (as in main iterator), direction FORWARD or BACKWARD (undef->forward).
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    $self->{NAV_MAP} = shift;
+    return undef unless ($self->{NAV_MAP});
+
+    $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource();
+    $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource();
+
+    # If the given resources are just the ID of the resource, get the
+    # objects
+    if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); }
+    if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); }
+
+    $self->{FILTER} = shift;
+
+    # A hash, used as a set, of resource already seen
+    $self->{ALREADY_SEEN} = shift;
+     if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
+    $self->{DIRECTION} = shift || FORWARD();
+
+    # Flag: Have we started yet?
+    $self->{STARTED} = 0;
+
+    # Should we continue calling the recursive iterator, if any?
+    $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+    # The recursive iterator, if any
+    $self->{RECURSIVE_ITERATOR} = undef;
+    # Are we recursing on a map, or a branch?
+    $self->{RECURSIVE_MAP} = 1; # we'll manually unset this when recursing on branches
+    # And the count of how deep it is, so that this iterator can keep track of
+    # when to pick back up again.
+    $self->{RECURSIVE_DEPTH} = 0;
+
+    # For keeping track of our branches, we maintain our own stack
+    $self->{STACK} = [];
+
+    # Start with the first resource
+    if ($self->{DIRECTION} == FORWARD) {
+        push @{$self->{STACK}}, $self->{FIRST_RESOURCE};
+    } else {
+        push @{$self->{STACK}}, $self->{FINISH_RESOURCE};
+    }
 
-# ------------------------------------------- Set document type for header only
+    bless($self);
+    return $self;
+}
 
-  if ($r->header_only) {
-       if ($ENV{'browser.mathml'}) {
-           $r->content_type('text/xml');
-       } else {
-           $r->content_type('text/html');
-       }
-       $r->send_http_header;
-       return OK;
-   }
-
-  my $requrl=$r->uri;
-# ----------------------------------------------------------------- Tie db file
-  if ($ENV{'request.course.fn'}) {
-      my $fn=$ENV{'request.course.fn'};
-      if (-e "$fn.db") {
-          if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) &&
-             (tie(%parmhash,'GDBM_File',
-           $ENV{'request.course.fn'}.'_parms.db',&GDBM_READER,0640))) {
-# ------------------------------------------------------------------- Hash tied
-              my $firstres=$hash{'map_start_/res/'.$ENV{'request.course.uri'}};
-              my $lastres=$hash{'map_finish_/res/'.$ENV{'request.course.uri'}};
-              if (($firstres) && ($lastres)) {
-# ----------------------------------------------------------------- Render page
-# -------------------------------------------------------------- Set parameters
-
-
-# ---------------------------- initialize coursedata and userdata for this user
-    undef %courseopt;
-    undef %useropt;
+sub next {
+    my $self = shift;
+    
+    # Are we using a recursive iterator? If so, pull from that and
+    # watch the depth; we want to resume our level at the correct time.
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        # grab the next from the recursive iterator
+        my $next = $self->{RECURSIVE_ITERATOR}->next();
+        
+        # is it a begin or end map? Update depth if so
+        if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; }
+        if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; }
+
+        # Are we back at depth 0? If so, stop recursing.
+        if ($self->{RECURSIVE_DEPTH} == 0) {
+            $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+        }
+        
+        return $next;
+    }
 
-    my $uname=$ENV{'user.name'};
-    my $udom=$ENV{'user.domain'};
-    my $uhome=$ENV{'user.home'};
-    my $cid=$ENV{'request.course.id'};
-    my $chome=$ENV{'course.'.$cid.'.home'};
-    my ($cdom,$cnum)=split(/\_/,$cid);
+    # Is there a current resource to grab? If not, then return
+    # END_MAP, which will end the iterator.
+    if (scalar(@{$self->{STACK}}) == 0) {
+        return $self->END_MAP();
+    }
 
-    my $userprefix=$uname.'_'.$udom.'_';
+    # Have we not yet begun? If not, return BEGIN_MAP and 
+    # remember that we've started.
+    if ( !$self->{STARTED} ) {
+        $self->{STARTED} = 1;
+        return $self->BEGIN_MAP;
+    }
 
-    unless ($uhome eq 'no_host') { 
-# -------------------------------------------------------------- Get coursedata
-      unless
-        ((time-$courserdatas{$cid.'.last_cache'})<240) {
-         my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
-              ':resourcedata',$chome);
-         if ($reply!~/^error\:/) {
-            $courserdatas{$cid}=$reply;
-            $courserdatas{$cid.'.last_cache'}=time;
-         }
-      }
-      map {
-         my ($name,$value)=split(/\=/,$_);
-         $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
-                    &Apache::lonnet::unescape($value);
-      } split(/\&/,$courserdatas{$cid});
-# --------------------------------------------------- Get userdata (if present)
-      unless
-        ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
-         my $reply=
-       &Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
-         if ($reply!~/^error\:/) {
-	     $userrdatas{$uname.'___'.$udom}=$reply;
-	     $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
-         }
-      }
-      map {
-         my ($name,$value)=split(/\=/,$_);
-         $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
-	          &Apache::lonnet::unescape($value);
-      } split(/\&/,$userrdatas{$uname.'___'.$udom});
-    }
-
-                  @rows=();
-
-                  &tracetable(0,$firstres,'&'.$lastres.'&');
-                  if ($hash{'src_'.$lastres}) {
-                     my $brepriv=
-                        &Apache::lonnet::allowed('bre',$hash{'src_'.$lastres});
-                     if (($brepriv eq '2') || ($brepriv eq 'F')) {
-                        $rows[$#rows+1]=''.$lastres;
-		     }
-		  }
-
-# ------------------------------------------------------------------ Page parms
-
-                  my $j;
-                  my $i;
-                  my $lcm=1;
-                  my $contents=0;
-
-# ---------------------------------------------- Go through table to get layout
-
-                  for ($i=0;$i<=$#rows;$i++) {
-		     if ($rows[$i]) {
-		      $contents++;
-                      my @colcont=split(/\&/,$rows[$i]);
-                      $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1));
-                     } 
-                  }
+    # Get the next resource in the branch
+    $self->{HERE} = pop @{$self->{STACK}};
 
+    # remember that we've seen this, so we don't return it again later
+    $self->{ALREADY_SEEN}->{$self->{HERE}->{ID}} = 1;
+    
+    # Get the next possible resources
+    my $nextUnfiltered;
+    if ($self->{DIRECTION} == FORWARD()) {
+        $nextUnfiltered = $self->{HERE}->getNext();
+    } else {
+        $nextUnfiltered = $self->{HERE}->getPrevious();
+    }
+    my $next = [];
+
+    # filter the next possibilities to remove things we've 
+    # already seen.
+    foreach (@$nextUnfiltered) {
+        if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
+            push @$next, $_;
+        }
+    }
 
-                  unless ($contents) {
-                      $r->content_type('text/html');
-                      $r->send_http_header;
-                      $r->print('<html><body>Empty Map.</body></html>');
-                  } else {
-
-# ------------------------------------------------------------------ Build page
-
-		      my $currenturl=$ENV{'form.postdata'};
-                      $currenturl=~s/^http\:\/\///;
-                      $currenturl=~s/^[^\/]+//;
-
-# ---------------------------------------------------------------- Send headers
-
-                          $r->content_type('text/html');
-                          &Apache::loncommon::no_cache($r);
-                          $r->send_http_header;
-		          my $date=localtime;
-                          $r->print(
-		   '<html><head><title>Navigate LON-CAPA Maps</title></head>');
-			  $r->print('<body bgcolor="#FFFFFF"');
-                          if (($currenturl=~/^\/res/) &&
-                              ($currenturl!~/^\/res\/adm/)) {
-                             $r->print(' onLoad="window.location.hash='.
-				       "'curloc'".'"');
-			  }
-                          $r->print('><script>window.focus();</script>'.
-                           '<img align=right src=/adm/lonIcons/lonlogos.gif>'.
-                                    '<h1>Navigate Course Map</h1>');
-		      $r->rflush();
-                      if (($currenturl=~/^\/res/) &&
-                          ($currenturl!~/^\/res\/adm/)) {
-		       $r->print('<a href="#curloc">Current Location</a><p>');
-                      }
-# ----------------------------------------------------- The little content list
-                      for ($i=0;$i<=$#rows;$i++) {
-			if ($rows[$i]) {
-                          my @colcont=split(/\&/,$rows[$i]);
-                          my $avespan=$lcm/($#colcont+1);
-                          for ($j=0;$j<=$#colcont;$j++) {
-                              my $rid=$colcont[$j];
-                              if ($rid=~/^h(.+)/) {
-				  $rid=$1;
-                                  $r->print(
-     '&nbsp;&nbsp;&nbsp;<a href="#'.$rid.'">'.$hash{'title_'.$rid}.'</a><br>');
-                              }
-                          }
-		        }
-                      }
-# ----------------------------------------------------------------- Start table
-                      $r->print('<hr><table cols="'.$lcm.'" border="0">');
-                      for ($i=0;$i<=$#rows;$i++) {
-			if ($rows[$i]) {
-                          $r->print("\n<tr>");
-                          my @colcont=split(/\&/,$rows[$i]);
-                          my $avespan=$lcm/($#colcont+1);
-                          for ($j=0;$j<=$#colcont;$j++) {
-                              my $rid=$colcont[$j];
-                              my $add='<td>&nbsp;&nbsp;';
-                              my $adde='</td>';
-                              my $hwk='<font color="#223322">';
-                              my $hwke='</font>';
-                              if ($rid=~/^h(.+)/) {
-				  $rid=$1;
-                                  $add=
-                                   '<th bgcolor="#AAFF55"><a name="'.$rid.'">';
-                                  $adde='</th>';
-                              }
-                            if ($rid=~/^p(\d)(\d)\"([\w\: \(\)\/\,]*)\"(.+)/) {
-                                  my $code=$1;
-                                  my $tcode=$2;
-                                  my $ctext=$3;
-                                  $rid=$4;
-                                  if ($tcode eq '1') {
-                                     $add='<td bgcolor="#AAAAAA">';
-                                  }
-                                  if ($code eq '3') {
-                                     $add='<td bgcolor="#AAFFAA">';
-				  } else {
-                                      $add='<td bgcolor="#FFAAAA">';
-				      if ($tcode eq '2') {
-                                         $add='<td bgcolor="#FFFFAA">';
-                                      }
-                                      if ($tcode eq '4') {
-                                         $add='<td bgcolor="#FFFF33"><blink>';
-                                         $adde='</blink></td>';
-                                      }
-                                  }
-                                  $hwk='<font color="#888811"><b>';
-                                  $hwke='</b></font>';
-                                  if ($code eq '1') {
-                                     $hwke='</b> ('.$ctext.')</font>';
-                                  }
-                                  if ($code eq '2') {
-                                     $hwk='<font color="#992222"><b>';
-                                     $hwke='</b> ('.$ctext.')</font>';
-                                  }
-                                  if ($code eq '3') {
-                                     $hwk='<font color="#229922"><b>';
-                                     $hwke='</b> ('.$ctext.')</font>';
-                                  }
-                              }
-			      if ($hash{'src_'.$rid} eq $currenturl) {
-                                  $add=$add.'<a name="curloc"></a>'.
-				      '<font color=red><b>-&gt; </b></font>';
-                                  $adde=
-                                '<font color=red><b> &lt;-</b></font>'.$adde;
-                              }
-                              $r->print($add.'<a href="'.$hash{'src_'.$rid}.
-                                '">'.$hwk.
-                                $hash{'title_'.$rid}.$hwke.'</a>'.$adde);
-                          }
-                          $r->print('</tr>');
-		        }
-                      }
-                      $r->print("\n</table>");
-                      $r->print('</body></html>');
-# -------------------------------------------------------------------- End page
-                  }                  
-# ------------------------------------------------------------- End render page
-              } else {
-                  $r->content_type('text/html');
-                  $r->send_http_header;
-		  $r->print('<html><body>Coursemap undefined.</body></html>');
-              }
-# ------------------------------------------------------------------ Untie hash
-              unless (untie(%hash)) {
-                   &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                       "Could not untie coursemap $fn (browse).</font>"); 
-              }
-              unless (untie(%parmhash)) {
-                   &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                       "Could not untie parmhash (browse).</font>"); 
-              }
-# -------------------------------------------------------------------- All done
-	      return OK;
-# ----------------------------------------------- Errors, hash could no be tied
-          }
-      } 
-  }
+    while (@$next) {
+        # copy the next possibilities over to the stack
+        push @{$self->{STACK}}, shift @$next;
+    }
+
+    # If this is a map and we want to recurse down it... (not filtered out)
+    if ($self->{HERE}->is_map() && 
+         (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) { 
+        $self->{RECURSIVE_ITERATOR_FLAG} = 1;
+        my $firstResource = $self->{HERE}->map_start();
+        my $finishResource = $self->{HERE}->map_finish();
+
+        $self->{RECURSIVE_ITERATOR} =
+          Apache::lonnavmaps::DFSiterator->new ($self->{NAV_MAP}, $firstResource, 
+                     $finishResource, $self->{FILTER}, $self->{ALREADY_SEEN},
+                                             $self->{CONDITION}, $self->{DIRECTION});
+    }
 
-  $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-  return HTTP_NOT_ACCEPTABLE; 
+    return $self->{HERE};
+}
+
+# Identical to the full iterator methods of the same name. Hate to copy/paste
+# but I also hate to "inherit" either iterator from the other.
+
+sub getStack {
+    my $self=shift;
+
+    my @stack;
+
+    $self->populateStack(\@stack);
+
+    return \@stack;
+}
+
+# Private method: Calls the iterators recursively to populate the stack.
+sub populateStack {
+    my $self=shift;
+    my $stack = shift;
+
+    push @$stack, $self->{HERE} if ($self->{HERE});
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        $self->{RECURSIVE_ITERATOR}->populateStack($stack);
+    }
 }
 
 1;
-__END__
 
+package Apache::lonnavmaps::resource;
+
+use Apache::lonnet;
+
+=pod
+
+=head1 Object: resource 
+
+X<resource, navmap object>
+A resource object encapsulates a resource in a resource map, allowing
+easy manipulation of the resource, querying the properties of the
+resource (including user properties), and represents a reference that
+can be used as the canonical representation of the resource by
+lonnavmap clients like renderers.
+
+A resource only makes sense in the context of a navmap, as some of the
+data is stored in the navmap object.
+
+You will probably never need to instantiate this object directly. Use
+Apache::lonnavmaps::navmap, and use the "start" method to obtain the
+starting resource.
+
+Resource objects respect the parameter_hiddenparts, which suppresses 
+various parts according to the wishes of the map author. As of this
+writing, there is no way to override this parameter, and suppressed
+parts will never be returned, nor will their response types or ids be
+stored.
+
+=head2 Overview
+
+A B<Resource> is the most granular type of object in LON-CAPA that can
+be included in a course. It can either be a particular resource, like
+an HTML page, external resource, problem, etc., or it can be a
+container sequence, such as a "page" or a "map".
+
+To see a sequence from the user's point of view, please see the
+B<Creating a Course: Maps and Sequences> chapter of the Author's
+Manual.
+
+A Resource Object, once obtained from a navmap object via a B<getBy*>
+method of the navmap, or from an iterator, allows you to query
+information about that resource.
+
+Generally, you do not ever want to create a resource object yourself,
+so creation has been left undocumented. Always retrieve resources
+from navmap objects.
+
+=head3 Identifying Resources
+
+X<big hash>Every resource is identified by a Resource ID in the big hash that is
+unique to that resource for a given course. X<resource ID, in big hash>
+The Resource ID has the form #.#, where the first number is the same
+for every resource in a map, and the second is unique. For instance,
+for a course laid out like this:
+
+ * Problem 1
+ * Map
+   * Resource 2
+   * Resource 3
+
+C<Problem 1> and C<Map> will share a first number, and C<Resource 2>
+C<Resource 3> will share a first number. The second number may end up
+re-used between the two groups.
+
+The resource ID is only used in the big hash, but can be used in the
+context of a course to identify a resource easily. (For instance, the
+printing system uses it to record which resources from a sequence you 
+wish to print.)
+
+X<symb> X<resource, symb>
+All resources also have B<symb>s, which uniquely identify a resource
+in a course. Many internal LON-CAPA functions expect a symb. A symb
+carries along with it the URL of the resource, and the map it appears
+in. Symbs are much larger then resource IDs.
+
+=cut
+
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    $self->{NAV_MAP} = shift;
+    $self->{ID} = shift;
+
+    # Store this new resource in the parent nav map's cache.
+    $self->{NAV_MAP}->{RESOURCE_CACHE}->{$self->{ID}} = $self;
+    $self->{RESOURCE_ERROR} = 0;
+
+    # A hash that can be used by two-pass algorithms to store data
+    # about this resource in. Not used by the resource object
+    # directly.
+    $self->{DATA} = {};
+   
+    bless($self);
+    
+    return $self;
+}
+
+# private function: simplify the NAV_HASH lookups we keep doing
+# pass the name, and to automatically append my ID, pass a true val on the
+# second param
+sub navHash {
+    my $self = shift;
+    my $param = shift;
+    my $id = shift;
+    return $self->{NAV_MAP}->navhash($param . ($id?$self->{ID}:""));
+}
+
+=pod
+
+=head2 Methods
+
+Once you have a resource object, here's what you can do with it:
 
+=head3 Attribute Retrieval
 
+Every resource has certain attributes that can be retrieved and used:
 
+=over 4
+
+=item * B<ID>: Every resource has an ID that is unique for that
+    resource in the course it is in. The ID is actually in the hash
+    representing the resource, so for a resource object $res, obtain
+    it via C<$res->{ID}).
+
+=item * B<compTitle>:
+
+Returns a "composite title", that is equal to $res->title() if the
+resource has a title, and is otherwise the last part of the URL (e.g.,
+"problem.problem").
+
+=item * B<ext>:
+
+Returns true if the resource is external.
+
+=item * B<kind>:
+
+Returns the kind of the resource from the compiled nav map.
+
+=item * B<randomout>:
+
+Returns true if this resource was chosen to NOT be shown to the user
+by the random map selection feature. In other words, this is usually
+false.
+
+=item * B<randompick>:
+
+Returns true for a map if the randompick feature is being used on the
+map. (?)
+
+=item * B<src>:
+
+Returns the source for the resource.
+
+=item * B<symb>:
+
+Returns the symb for the resource.
+
+=item * B<title>:
+
+Returns the title of the resource.
+
+=back
+
+=cut
+
+# These info functions can be used directly, as they don't return
+# resource information.
+sub comesfrom { my $self=shift; return $self->navHash("comesfrom_", 1); }
+sub ext { my $self=shift; return $self->navHash("ext_", 1) eq 'true:'; }
+sub from { my $self=shift; return $self->navHash("from_", 1); }
+# considered private and undocumented
+sub goesto { my $self=shift; return $self->navHash("goesto_", 1); }
+sub kind { my $self=shift; return $self->navHash("kind_", 1); }
+sub randomout { my $self=shift; return $self->navHash("randomout_", 1); }
+sub randompick { 
+    my $self = shift;
+    return $self->{NAV_MAP}->{PARM_HASH}->{$self->symb .
+                                               '.0.parameter_randompick'};
+}
+sub src { 
+    my $self=shift;
+    return $self->navHash("src_", 1);
+}
+sub symb {
+    my $self=shift;
+    (my $first, my $second) = $self->{ID} =~ /(\d+).(\d+)/;
+    my $symbSrc = &Apache::lonnet::declutter($self->src());
+    return &Apache::lonnet::declutter(
+         $self->navHash('map_id_'.$first)) 
+        . '___' . $second . '___' . $symbSrc;
+}
+sub title { 
+    my $self=shift; 
+    if ($self->{ID} eq '0.0') {
+	# If this is the top-level map, return the title of the course
+	# since this map can not be titled otherwise.
+	return $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
+    }
+    return $self->navHash("title_", 1); }
+# considered private and undocumented
+sub to { my $self=shift; return $self->navHash("to_", 1); }
+sub compTitle {
+    my $self = shift;
+    my $title = $self->title();
+    $title=~s/\&colon\;/\:/gs;
+    if (!$title) {
+        $title = $self->src();
+        $title = substr($title, rindex($title, '/') + 1);
+    }
+    return $title;
+}
+=pod
+
+B<Predicate Testing the Resource>
+
+These methods are shortcuts to deciding if a given resource has a given property.
+
+=over 4
+
+=item * B<is_map>:
+
+Returns true if the resource is a map type.
+
+=item * B<is_problem>:
+
+Returns true if the resource is a problem type, false
+otherwise. (Looks at the extension on the src field; might need more
+to work correctly.)
+
+=item * B<is_page>:
+
+Returns true if the resource is a page.
+
+=item * B<is_sequence>:
+
+Returns true if the resource is a sequence.
+
+=back
+
+=cut
+
+
+sub is_html {
+    my $self=shift;
+    my $src = $self->src();
+    return ($src =~ /html$/);
+}
+sub is_map { my $self=shift; return defined($self->navHash("is_map_", 1)); }
+sub is_page {
+    my $self=shift;
+    my $src = $self->src();
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'page';
+}
+sub is_problem {
+    my $self=shift;
+    my $src = $self->src();
+    return ($src =~ /problem$/);
+}
+sub is_sequence {
+    my $self=shift;
+    my $src = $self->src();
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'sequence';
+}
+
+# Private method: Shells out to the parmval in the nav map, handler parts.
+sub parmval {
+    my $self = shift;
+    my $what = shift;
+    my $part = shift;
+    if (!defined($part)) { 
+        $part = '0'; 
+    }
+    return $self->{NAV_MAP}->parmval($part.'.'.$what, $self->symb());
+}
+
+=pod
+
+B<Map Methods>
+
+These methods are useful for getting information about the map
+properties of the resource, if the resource is a map (B<is_map>).
+
+=over 4
+
+=item * B<map_finish>:
+
+Returns a reference to a resource object corresponding to the finish
+resource of the map.
+
+=item * B<map_pc>:
+
+Returns the pc value of the map, which is the first number that
+appears in the resource ID of the resources in the map, and is the
+number that appears around the middle of the symbs of the resources in
+that map.
+
+=item * B<map_start>:
+
+Returns a reference to a resource object corresponding to the start
+resource of the map.
+
+=item * B<map_type>:
+
+Returns a string with the type of the map in it.
+
+=back
+
+=cut
+
+sub map_finish {
+    my $self = shift;
+    my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
+    my $res = $self->navHash("map_finish_$src", 0);
+    $res = $self->{NAV_MAP}->getById($res);
+    return $res;
+}
+sub map_pc {
+    my $self = shift;
+    my $src = $self->src();
+    return $self->navHash("map_pc_$src", 0);
+}
+sub map_start {
+    my $self = shift;
+    my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
+    my $res = $self->navHash("map_start_$src", 0);
+    $res = $self->{NAV_MAP}->getById($res);
+    return $res;
+}
+sub map_type {
+    my $self = shift;
+    my $pc = $self->map_pc();
+    return $self->navHash("map_type_$pc", 0);
+}
+
+#####
+# Property queries
+#####
+
+# These functions will be responsible for returning the CORRECT
+# VALUE for the parameter, no matter what. So while they may look
+# like direct calls to parmval, they can be more then that.
+# So, for instance, the duedate function should use the "duedatetype"
+# information, rather then the resource object user.
+
+=pod
+
+=head2 Resource Parameters
+
+In order to use the resource parameters correctly, the nav map must
+have been instantiated with genCourseAndUserOptions set to true, so
+the courseopt and useropt is read correctly. Then, you can call these
+functions to get the relevant parameters for the resource. Each
+function defaults to part "0", but can be directed to another part by
+passing the part as the parameter.
+
+These methods are responsible for getting the parameter correct, not
+merely reflecting the contents of the GDBM hashes. As we move towards
+dates relative to other dates, these methods should be updated to
+reflect that. (Then, anybody using these methods will not have to update
+their code.)
+
+=over 4
+
+=item * B<acc>:
+
+Get the Client IP/Name Access Control information.
+
+=item * B<answerdate>:
+
+Get the answer-reveal date for the problem.
+
+=item * B<awarded>: 
+
+Gets the awarded value for the problem part. Requires genUserData set to
+true when the navmap object was created.
+
+=item * B<duedate>:
+
+Get the due date for the problem.
+
+=item * B<tries>:
+
+Get the number of tries the student has used on the problem.
+
+=item * B<maxtries>:
+
+Get the number of max tries allowed.
+
+=item * B<opendate>:
+
+Get the open date for the problem.
+
+=item * B<sig>:
+
+Get the significant figures setting.
+
+=item * B<tol>:
+
+Get the tolerance for the problem.
+
+=item * B<tries>:
+
+Get the number of tries the user has already used on the problem.
+
+=item * B<type>:
+
+Get the question type for the problem.
+
+=item * B<weight>:
+
+Get the weight for the problem.
+
+=back
+
+=cut
+
+sub acc {
+    (my $self, my $part) = @_;
+    return $self->parmval("acc", $part);
+}
+sub answerdate {
+    (my $self, my $part) = @_;
+    # Handle intervals
+    if ($self->parmval("answerdate.type", $part) eq 'date_interval') {
+        return $self->duedate($part) + 
+            $self->parmval("answerdate", $part);
+    }
+    return $self->parmval("answerdate", $part);
+}
+sub awarded { 
+    my $self = shift; my $part = shift;
+    if (!defined($part)) { $part = '0'; }
+    return $self->{NAV_MAP}->{STUDENT_DATA}->{$self->symb()}->{'resource.'.$part.'.awarded'};
+}
+sub duedate {
+    (my $self, my $part) = @_;
+    return $self->parmval("duedate", $part);
+}
+sub maxtries {
+    (my $self, my $part) = @_;
+    return $self->parmval("maxtries", $part);
+}
+sub opendate {
+    (my $self, my $part) = @_;
+    if ($self->parmval("opendate.type", $part) eq 'date_interval') {
+        return $self->duedate($part) -
+            $self->parmval("opendate", $part);
+    }
+    return $self->parmval("opendate");
+}
+sub problemstatus {
+    (my $self, my $part) = @_;
+    return $self->parmval("problemstatus", $part);
+}
+sub sig {
+    (my $self, my $part) = @_;
+    return $self->parmval("sig", $part);
+}
+sub tol {
+    (my $self, my $part) = @_;
+    return $self->parmval("tol", $part);
+}
+sub tries { 
+    my $self = shift; 
+    my $tries = $self->queryRestoreHash('tries', shift);
+    if (!defined($tries)) { return '0';}
+    return $tries;
+}
+sub type {
+    (my $self, my $part) = @_;
+    return $self->parmval("type", $part);
+}
+sub weight { 
+    my $self = shift; my $part = shift;
+    if (!defined($part)) { $part = '0'; }
+    return &Apache::lonnet::EXT('resource.'.$part.'.weight',
+				$self->symb(), $ENV{'user.domain'},
+				$ENV{'user.name'}, 
+				$ENV{'request.course.sec'});
+
+}
 
+# Multiple things need this
+sub getReturnHash {
+    my $self = shift;
+    
+    if (!defined($self->{RETURN_HASH})) {
+        my %tmpHash  = &Apache::lonnet::restore($self->symb());
+        $self->{RETURN_HASH} = \%tmpHash;
+    }
+}       
+
+######
+# Status queries
+######
+
+# These methods query the status of problems.
+
+# If we need to count parts, this function determines the number of
+# parts from the metadata. When called, it returns a reference to a list
+# of strings corresponding to the parts. (Thus, using it in a scalar context
+# tells you how many parts you have in the problem:
+# $partcount = scalar($resource->countParts());
+# Don't use $self->{PARTS} directly because you don't know if it's been
+# computed yet.
+
+=pod
+
+=head2 Resource misc
+
+Misc. functions for the resource.
+
+=over 4
+
+=item * B<hasDiscussion>:
+
+Returns a false value if there has been discussion since the user last
+logged in, true if there has. Always returns false if the discussion
+data was not extracted when the nav map was constructed.
+
+=item * B<getFeedback>:
+
+Gets the feedback for the resource and returns the raw feedback string
+for the resource, or the null string if there is no feedback or the
+email data was not extracted when the nav map was constructed. Usually
+used like this:
+
+ for (split(/\,/, $res->getFeedback())) {
+    my $link = &Apache::lonnet::escape($_);
+    ...
+
+and use the link as appropriate.
+
+=cut
+
+sub hasDiscussion {
+    my $self = shift;
+    return $self->{NAV_MAP}->hasDiscussion($self->symb());
+}
+
+sub getFeedback {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getFeedback($source);
+}
+
+sub getErrors {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getErrors($source);
+}
+
+=pod
+
+=item * B<parts>():
+
+Returns a list reference containing sorted strings corresponding to
+each part of the problem. Single part problems have only a part '0'.
+Multipart problems do not return their part '0', since they typically
+do not really matter. 
+
+=item * B<countParts>():
+
+Returns the number of parts of the problem a student can answer. Thus,
+for single part problems, returns 1. For multipart, it returns the
+number of parts in the problem, not including psuedo-part 0. 
+
+=item * B<multipart>():
+
+Returns true if the problem is multipart, false otherwise. Use this instead
+of countParts if all you want is multipart/not multipart.
+
+=item * B<responseType>($part):
+
+Returns the response type of the part, without the word "response" on the
+end. Example return values: 'string', 'essay', 'numeric', etc.
+
+=item * B<responseIds>($part):
+
+Retreives the response IDs for the given part as an array reference containing
+strings naming the response IDs. This may be empty.
+
+=back
+
+=cut
+
+sub parts {
+    my $self = shift;
+
+    if ($self->ext) { return []; }
+
+    $self->extractParts();
+    return $self->{PARTS};
+}
+
+sub countParts {
+    my $self = shift;
+    
+    my $parts = $self->parts();
+
+    # If I left this here, then it's not necessary.
+    #my $delta = 0;
+    #for my $part (@$parts) {
+    #    if ($part eq '0') { $delta--; }
+    #}
+
+    if ($self->{RESOURCE_ERROR}) {
+        return 0;
+    }
+
+    return scalar(@{$parts}); # + $delta;
+}
+
+sub multipart {
+    my $self = shift;
+    return $self->countParts() > 1;
+}
+
+sub responseType {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    return $self->{RESPONSE_TYPES}->{$part};
+}
+
+sub responseIds {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    return $self->{RESPONSE_IDS}->{$part};
+}
+
+# Private function: Extracts the parts information, both part names and
+# part types, and saves it. 
+sub extractParts { 
+    my $self = shift;
+    
+    return if (defined($self->{PARTS}));
+    return if ($self->ext);
+
+    $self->{PARTS} = [];
+
+    my %parts;
+
+    # Retrieve part count, if this is a problem
+    if ($self->is_problem()) {
+        my $metadata = &Apache::lonnet::metadata($self->src(), 'packages');
+        if (!$metadata) {
+            $self->{RESOURCE_ERROR} = 1;
+            $self->{PARTS} = [];
+            $self->{PART_TYPE} = {};
+            return;
+        }
+        foreach (split(/\,/,$metadata)) {
+            if ($_ =~ /^part_(.*)$/) {
+                my $part = $1;
+                # This floods the logs if it blows up
+                if (defined($parts{$part})) {
+                    Apache::lonnet::logthis("$part multiply defined in metadata for " . $self->symb());
+                  }
+
+                # check to see if part is turned off.
+
+                if (!Apache::loncommon::check_if_partid_hidden($part, $self->symb())) {
+                    $parts{$part} = 1;
+                }
+            }
+        }
+        
+        
+        my @sortedParts = sort keys %parts;
+        $self->{PARTS} = \@sortedParts;
+
+        my %responseIdHash;
+        my %responseTypeHash;
+
+
+        # Init the responseIdHash
+        foreach (@{$self->{PARTS}}) {
+            $responseIdHash{$_} = [];
+        }
+
+        # Now, the unfortunate thing about this is that parts, part name, and
+        # response if are delimited by underscores, but both the part
+        # name and response id can themselves have underscores in them.
+        # So we have to use our knowlege of part names to figure out 
+        # where the part names begin and end, and even then, it is possible
+        # to construct ambiguous situations.
+        foreach (split /,/, $metadata) {
+            if ($_ =~ /^([a-zA-Z]+)response_(.*)/) {
+                my $responseType = $1;
+                my $partStuff = $2;
+                my $partIdSoFar = '';
+                my @partChunks = split /_/, $partStuff;
+                my $i = 0;
+
+                for ($i = 0; $i < scalar(@partChunks); $i++) {
+                    if ($partIdSoFar) { $partIdSoFar .= '_'; }
+                    $partIdSoFar .= $partChunks[$i];
+                    if ($parts{$partIdSoFar}) {
+                        my @otherChunks = @partChunks[$i+1..$#partChunks];
+                        my $responseId = join('_', @otherChunks);
+                        push @{$responseIdHash{$partIdSoFar}}, $responseId;
+                        $responseTypeHash{$partIdSoFar} = $responseType;
+                        last;
+                    }
+                }
+            }
+        }
+
+        $self->{RESPONSE_IDS} = \%responseIdHash;
+        $self->{RESPONSE_TYPES} = \%responseTypeHash;
+    }
+
+    return;
+}
+
+=pod
+
+=head2 Resource Status
+
+Problem resources have status information, reflecting their various
+dates and completion statuses.
+
+There are two aspects to the status: the date-related information and
+the completion information.
+
+Idiomatic usage of these two methods would probably look something
+like
+
+ foreach ($resource->parts()) {
+    my $dateStatus = $resource->getDateStatus($_);
+    my $completionStatus = $resource->getCompletionStatus($_);
+
+    or
+
+    my $status = $resource->status($_);
+
+    ... use it here ...
+ }
+
+Which you use depends on exactly what you are looking for. The
+status() function has been optimized for the nav maps display and may
+not precisely match what you need elsewhere.
+
+The symbolic constants shown below can be accessed through the
+resource object: C<$res->OPEN>.
+
+=over 4
+
+=item * B<getDateStatus>($part):
+
+($part defaults to 0). A convenience function that returns a symbolic
+constant telling you about the date status of the part. The possible
+return values are:
+
+=back
+
+B<Date Codes>
+
+=over 4
+
+=item * B<OPEN_LATER>:
+
+The problem will be opened later.
+
+=item * B<OPEN>:
+
+Open and not yet due.
+
+
+=item * B<PAST_DUE_ANSWER_LATER>:
+
+The due date has passed, but the answer date has not yet arrived.
+
+=item * B<PAST_DUE_NO_ANSWER>:
+
+The due date has passed and there is no answer opening date set.
+
+=item * B<ANSWER_OPEN>:
+
+The answer date is here.
+
+=item * B<NETWORK_FAILURE>:
+
+The information is unknown due to network failure.
+
+=back
+
+=cut
+
+# Apparently the compiler optimizes these into constants automatically
+sub OPEN_LATER             { return 0; }
+sub OPEN                   { return 1; }
+sub PAST_DUE_NO_ANSWER     { return 2; }
+sub PAST_DUE_ANSWER_LATER  { return 3; }
+sub ANSWER_OPEN            { return 4; }
+sub NOTHING_SET            { return 5; } 
+sub NETWORK_FAILURE        { return 100; }
+
+# getDateStatus gets the date status for a given problem part. 
+# Because answer date, due date, and open date are fully independent
+# (i.e., it is perfectly possible to *only* have an answer date), 
+# we have to completely cover the 3x3 maxtrix of (answer, due, open) x
+# (past, future, none given). This function handles this with a decision
+# tree. Read the comments to follow the decision tree.
+
+sub getDateStatus {
+    my $self = shift;
+    my $part = shift;
+    $part = "0" if (!defined($part));
+
+    # Always return network failure if there was one.
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    my $now = time();
+
+    my $open = $self->opendate($part);
+    my $due = $self->duedate($part);
+    my $answer = $self->answerdate($part);
+
+    if (!$open && !$due && !$answer) {
+        # no data on the problem at all
+        # should this be the same as "open later"? think multipart.
+        return $self->NOTHING_SET;
+    }
+    if (!$open || $now < $open) {return $self->OPEN_LATER}
+    if (!$due || $now < $due) {return $self->OPEN}
+    if ($answer && $now < $answer) {return $self->PAST_DUE_ANSWER_LATER}
+    if ($answer) { return $self->ANSWER_OPEN; }
+    return PAST_DUE_NO_ANSWER;
+}
+
+=pod
+
+B<>
+
+=over 4
+
+=item * B<getCompletionStatus>($part):
+
+($part defaults to 0.) A convenience function that returns a symbolic
+constant telling you about the completion status of the part, with the
+following possible results:
+
+=back
+
+B<Completion Codes>
+
+=over 4
+
+=item * B<NOT_ATTEMPTED>:
+
+Has not been attempted at all.
+
+=item * B<INCORRECT>:
+
+Attempted, but wrong by student.
+
+=item * B<INCORRECT_BY_OVERRIDE>:
+
+Attempted, but wrong by instructor override.
+
+=item * B<CORRECT>:
+
+Correct or correct by instructor.
+
+=item * B<CORRECT_BY_OVERRIDE>:
+
+Correct by instructor override.
+
+=item * B<EXCUSED>:
+
+Excused. Not yet implemented.
+
+=item * B<NETWORK_FAILURE>:
+
+Information not available due to network failure.
+
+=item * B<ATTEMPTED>:
+
+Attempted, and not yet graded.
+
+=back
+
+=cut
+
+sub NOT_ATTEMPTED         { return 10; }
+sub INCORRECT             { return 11; }
+sub INCORRECT_BY_OVERRIDE { return 12; }
+sub CORRECT               { return 13; }
+sub CORRECT_BY_OVERRIDE   { return 14; }
+sub EXCUSED               { return 15; }
+sub ATTEMPTED             { return 16; }
+
+sub getCompletionStatus {
+    my $self = shift;
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    my $status = $self->queryRestoreHash('solved', shift);
+
+    # Left as seperate if statements in case we ever do more with this
+    if ($status eq 'correct_by_student') {return $self->CORRECT;}
+    if ($status eq 'correct_by_override') {return $self->CORRECT_BY_OVERRIDE; }
+    if ($status eq 'incorrect_attempted') {return $self->INCORRECT; }
+    if ($status eq 'incorrect_by_override') {return $self->INCORRECT_BY_OVERRIDE; }
+    if ($status eq 'excused') {return $self->EXCUSED; }
+    if ($status eq 'ungraded_attempted') {return $self->ATTEMPTED; }
+    return $self->NOT_ATTEMPTED;
+}
+
+sub queryRestoreHash {
+    my $self = shift;
+    my $hashentry = shift;
+    my $part = shift;
+    $part = "0" if (!defined($part) || $part eq '');
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    $self->getReturnHash();
+
+    return $self->{RETURN_HASH}->{'resource.'.$part.'.'.$hashentry};
+}
+
+=pod
+
+B<Composite Status>
+
+Along with directly returning the date or completion status, the
+resource object includes a convenience function B<status>() that will
+combine the two status tidbits into one composite status that can
+represent the status of the resource as a whole. This method represents
+the concept of the thing we want to display to the user on the nav maps
+screen, which is a combination of completion and open status. The precise logic is
+documented in the comments of the status method. The following results
+may be returned, all available as methods on the resource object
+($res->NETWORK_FAILURE): In addition to the return values that match
+the date or completion status, this function can return "ANSWER_SUBMITTED"
+if that problemstatus parameter value is set to No, suppressing the
+incorrect/correct feedback.
+
+=over 4
+
+=item * B<NETWORK_FAILURE>:
+
+The network has failed and the information is not available.
+
+=item * B<NOTHING_SET>:
+
+No dates have been set for this problem (part) at all. (Because only
+certain parts of a multi-part problem may be assigned, this can not be
+collapsed into "open later", as we do not know a given part will EVER
+be opened. For single part, this is the same as "OPEN_LATER".)
+
+=item * B<CORRECT>:
+
+For any reason at all, the part is considered correct.
+
+=item * B<EXCUSED>:
+
+For any reason at all, the problem is excused.
+
+=item * B<PAST_DUE_NO_ANSWER>:
+
+The problem is past due, not considered correct, and no answer date is
+set.
+
+=item * B<PAST_DUE_ANSWER_LATER>:
+
+The problem is past due, not considered correct, and an answer date in
+the future is set.
+
+=item * B<ANSWER_OPEN>:
+
+The problem is past due, not correct, and the answer is now available.
+
+=item * B<OPEN_LATER>:
+
+The problem is not yet open.
+
+=item * B<TRIES_LEFT>:
+
+The problem is open, has been tried, is not correct, but there are
+tries left.
+
+=item * B<INCORRECT>:
+
+The problem is open, and all tries have been used without getting the
+correct answer.
+
+=item * B<OPEN>:
+
+The item is open and not yet tried.
+
+=item * B<ATTEMPTED>:
+
+The problem has been attempted.
+
+=item * B<ANSWER_SUBMITTED>:
+
+An answer has been submitted, but the student should not see it.
+
+=back
+
+=cut
+
+sub TRIES_LEFT       { return 20; }
+sub ANSWER_SUBMITTED { return 21; }
+
+sub status {
+    my $self = shift;
+    my $part = shift;
+    if (!defined($part)) { $part = "0"; }
+    my $completionStatus = $self->getCompletionStatus($part);
+    my $dateStatus = $self->getDateStatus($part);
+
+    # What we have is a two-dimensional matrix with 4 entries on one
+    # dimension and 5 entries on the other, which we want to colorize,
+    # plus network failure and "no date data at all".
+
+    if ($completionStatus == NETWORK_FAILURE) { return NETWORK_FAILURE; }
+
+    my $suppressFeedback = lc($self->parmval("problemstatus", $part)) eq 'no';
+
+    # There are a few whole rows we can dispose of:
+    if ($completionStatus == CORRECT ||
+        $completionStatus == CORRECT_BY_OVERRIDE ) {
+        return $suppressFeedback? ANSWER_SUBMITTED : CORRECT; 
+    }
+
+    if ($completionStatus == ATTEMPTED) {
+        return ATTEMPTED;
+    }
+
+    # If it's EXCUSED, then return that no matter what
+    if ($completionStatus == EXCUSED) {
+        return EXCUSED; 
+    }
+
+    if ($dateStatus == NOTHING_SET) {
+        return NOTHING_SET;
+    }
+
+    # Now we're down to a 4 (incorrect, incorrect_override, not_attempted)
+    # by 4 matrix (date statuses).
+
+    if ($dateStatus == PAST_DUE_ANSWER_LATER ||
+        $dateStatus == PAST_DUE_NO_ANSWER ) {
+        return $dateStatus; 
+    }
+
+    if ($dateStatus == ANSWER_OPEN) {
+        return ANSWER_OPEN;
+    }
+
+    # Now: (incorrect, incorrect_override, not_attempted) x 
+    # (open_later), (open)
+    
+    if ($dateStatus == OPEN_LATER) {
+        return OPEN_LATER;
+    }
+
+    # If it's WRONG...
+    if ($completionStatus == INCORRECT || $completionStatus == INCORRECT_BY_OVERRIDE) {
+        # and there are TRIES LEFT:
+        if ($self->tries($part) < $self->maxtries($part) || !$self->maxtries($part)) {
+	    return $suppressFeedback ? ANSWER_SUBMITTED : TRIES_LEFT;
+	}
+        return $suppressFeedback ? ANSWER_SUBMITTED : INCORRECT; # otherwise, return orange; student can't fix this
+    }
+
+    # Otherwise, it's untried and open
+    return OPEN; 
+}
+
+=pod
+
+B<Completable>
+
+The completable method represents the concept of I<whether the student can
+currently do the problem>. If the student can do the problem, which means
+that it is open, there are tries left, and if the problem is manually graded
+or the grade is suppressed via problemstatus, the student has not tried it
+yet, then the method returns 1. Otherwise, it returns 0, to indicate that 
+either the student has tried it and there is no feedback, or that for
+some reason it is no longer completable (not open yet, successfully completed,
+out of tries, etc.). As an example, this is used as the filter for the
+"Uncompleted Homework" option for the nav maps.
+
+If this does not quite meet your needs, do not fiddle with it (unless you are
+fixing it to better match the student's conception of "completable" because
+it's broken somehow)... make a new method.
+
+=cut
+
+sub completable {
+    my $self = shift;
+    if (!$self->is_problem()) { return 0; }
+    my $partCount = $self->countParts();
+
+    foreach my $part (@{$self->parts()}) {
+        if ($part eq '0' && $partCount != 1) { next; }
+        my $status = $self->status($part);
+        # "If any of the parts are open, or have tries left (implies open),
+        # and it is not "attempted" (manually graded problem), it is
+        # not "complete"
+	if ($self->getCompletionStatus($part) == ATTEMPTED() ||
+	    $status == ANSWER_SUBMITTED() ) {
+	    # did this part already, as well as we can
+	    next;
+	}
+	if ($status == OPEN() || $status == TRIES_LEFT()) {
+	    return 1;
+	}
+    }
+        
+    # If all the parts were complete, so was this problem.
+    return 0;
+}
+
+=pod
+
+=head2 Resource/Nav Map Navigation
+
+=over 4
+
+=item * B<getNext>():
+
+Retreive an array of the possible next resources after this
+one. Always returns an array, even in the one- or zero-element case.
+
+=item * B<getPrevious>():
+
+Retreive an array of the possible previous resources from this
+one. Always returns an array, even in the one- or zero-element case.
+
+=cut
+
+sub getNext {
+    my $self = shift;
+    my @branches;
+    my $to = $self->to();
+    foreach my $branch ( split(/,/, $to) ) {
+        my $choice = $self->{NAV_MAP}->getById($branch);
+        my $next = $choice->goesto();
+        $next = $self->{NAV_MAP}->getById($next);
+
+        push @branches, $next;
+    }
+    return \@branches;
+}
+
+sub getPrevious {
+    my $self = shift;
+    my @branches;
+    my $from = $self->from();
+    foreach my $branch ( split /,/, $from) {
+        my $choice = $self->{NAV_MAP}->getById($branch);
+        my $prev = $choice->comesfrom();
+        $prev = $self->{NAV_MAP}->getById($prev);
+
+        push @branches, $prev;
+    }
+    return \@branches;
+}
+
+sub browsePriv {
+    my $self = shift;
+    if (defined($self->{BROWSE_PRIV})) {
+        return $self->{BROWSE_PRIV};
+    }
+
+    $self->{BROWSE_PRIV} = &Apache::lonnet::allowed('bre', $self->src());
+}
+
+=pod
+
+=back
+
+=cut
+
+1;
+
+__END__