--- loncom/interface/statistics/lonstathelpers.pm	2004/01/19 21:29:46	1.1
+++ loncom/interface/statistics/lonstathelpers.pm	2004/03/08 19:12:18	1.6
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonstathelpers.pm,v 1.1 2004/01/19 21:29:46 matthew Exp $
+# $Id: lonstathelpers.pm,v 1.6 2004/03/08 19:12:18 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -94,6 +94,685 @@ sub render_resource {
         '</td></tr></table>';
 }
 
+####################################################
+####################################################
+
+=pod
+
+=item &ProblemSelector($AcceptedResponseTypes)
+
+Input: scalar containing regular expression which matches response
+types to show.  '.' will yield all, '(option|radiobutton)' will match
+all option response and radiobutton problems.
+
+Returns: A string containing html for a table which lists the sequences
+and their contents.  A radiobutton is provided for each problem.
+
+=cut
+
+####################################################
+####################################################
+sub ProblemSelector {
+    my ($AcceptedResponseTypes) = @_;
+    my $Str;
+    $Str = "\n<table>\n";
+    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
+        next if ($seq->{'num_assess'}<1);
+        my $seq_str = '';
+        foreach my $res (@{$seq->{'contents'}}) {
+            next if ($res->{'type'} ne 'assessment');
+            foreach my $part (@{$res->{'parts'}}) {
+                my $partdata = $res->{'partdata'}->{$part};
+                for (my $i=0;$i<scalar(@{$partdata->{'ResponseTypes'}});$i++){
+                    my $respid = $partdata->{'ResponseIds'}->[$i];
+                    my $resptype = $partdata->{'ResponseTypes'}->[$i];
+                    if ($resptype =~ m/$AcceptedResponseTypes/) {
+                        my $value = &make_target_id({symb=>$res->{'symb'},
+                                                     part=>$part,
+                                                     respid=>$respid,
+                                                     resptype=>$resptype});
+                        my $checked = '';
+                        if ($ENV{'form.problemchoice'} eq $value) {
+                            $checked = 'checked ';
+                        }
+                        my $title = $res->{'title'};
+                        if (! defined($title) || $title eq '') {
+                            ($title) = ($res->{'src'} =~ m:/([^/]*)$:);
+                        }
+                        $seq_str .= '<tr><td>'.
+  '<input type="radio" name="problemchoice" value="'.$value.'" '.$checked.'/>'.
+  '</td><td>'.          
+  $resptype.'</td><td>'.
+  '<a href="'.$res->{'src'}.'">'.$title.'</a> ';
+#  '<a href="'.$res->{'src'}.'">'.$resptype.' '.$res->{'title'}.'</a> ';
+                        if (scalar(@{$partdata->{'ResponseIds'}}) > 1) {
+                            $seq_str .= &mt('response').' '.$respid;
+                        }
+                        $seq_str .= "</td></tr>\n";
+                    }
+                }
+            }
+        }
+        if ($seq_str ne '') {
+            $Str .= '<tr><td>&nbsp</td><td colspan="2"><b>'.$seq->{'title'}.'</b></td>'.
+                "</tr>\n".$seq_str;
+        }
+    }
+    $Str .= "</table>\n";
+    return $Str;
+}
+
+####################################################
+####################################################
+
+=pod
+
+=item &make_target_id($target)
+
+Inputs: Hash ref with the following entries:
+    $target->{'symb'}, $target->{'part'}, $target->{'respid'}, 
+    $target->{'resptype'}.
+
+Returns: A string, suitable for a form parameter, which uniquely identifies
+the problem, part, and response to do statistical analysis on.
+
+Used by Apache::lonstathelpers::ProblemSelector().
+
+=cut
+
+####################################################
+####################################################
+sub make_target_id {
+    my ($target) = @_;
+    my $id = &Apache::lonnet::escape($target->{'symb'}).':'.
+             &Apache::lonnet::escape($target->{'part'}).':'.
+             &Apache::lonnet::escape($target->{'respid'}).':'.
+             &Apache::lonnet::escape($target->{'resptype'});
+    return $id;
+}
+
+####################################################
+####################################################
+
+=pod
+
+=item &get_target_from_id($id)
+
+Inputs: $id, a scalar string from Apache::lonstathelpers::make_target_id().
+
+Returns: A hash reference, $target, containing the following keys:
+    $target->{'symb'}, $target->{'part'}, $target->{'respid'}, 
+    $target->{'resptype'}.
+
+=cut
+
+####################################################
+####################################################
+sub get_target_from_id {
+    my ($id) = @_;
+    my ($symb,$part,$respid,$resptype) = split(':',$id);
+    return ({ symb    =>&Apache::lonnet::unescape($symb),
+             part     =>&Apache::lonnet::unescape($part),
+             respid   =>&Apache::lonnet::unescape($respid),
+             resptype =>&Apache::lonnet::unescape($resptype)});
+}
+
+####################################################
+####################################################
+
+=pod
+
+=item &get_prev_curr_next($target)
+
+Determine the problem parts or responses preceeding and following the
+current resource.
+
+Inputs: $target (see &Apache::lonstathelpers::get_target_from_id())
+  $AcceptableResponseTypes, regular expression matching acceptable
+                            response types,
+  $granularity, either 'part' or 'response'
+
+Returns: three hash references, $prev, $curr, $next, which refer to the
+preceeding, current, or following problem parts or responses, depending
+on the value of $granularity.  Values of undef indicate there is no
+previous or next part/response.  A value of undef for all three indicates
+there was no match found to the current part/resource.
+
+The hash references contain the following keys:
+    symb, part, resource
+
+If $granularity eq 'response', the following ADDITIONAL keys will be present:
+    respid, resptype
+
+=cut
+
+####################################################
+####################################################
+sub get_prev_curr_next {
+    my ($target,$AcceptableResponseTypes,$granularity) = @_;
+    #
+    # Build an array with the data we need to search through
+    my @Resource;
+    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
+        foreach my $res (@{$seq->{'contents'}}) {
+            next if ($res->{'type'} ne 'assessment');
+            foreach my $part (@{$res->{'parts'}}) {
+                my $partdata = $res->{'partdata'}->{$part};
+                if ($granularity eq 'part') {
+                    push (@Resource,
+                          { symb     => $res->{symb},
+                            part     => $part,
+                            resource => $res,
+                        } );
+                } elsif ($granularity eq 'response') {
+                    for (my $i=0;
+                         $i<scalar(@{$partdata->{'ResponseTypes'}});
+                         $i++){
+                        my $respid = $partdata->{'ResponseIds'}->[$i];
+                        my $resptype = $partdata->{'ResponseTypes'}->[$i];
+                        next if ($resptype !~ m/$AcceptableResponseTypes/);
+                        push (@Resource,
+                              { symb     => $res->{symb},
+                                part     => $part,
+                                respid   => $partdata->{'ResponseIds'}->[$i],
+                                resource => $res,
+                                resptype => $resptype
+                                } );
+                    }
+                }
+            }
+        }
+    }
+    #
+    # Get the index of the current situation
+    my $curr_idx;
+    for ($curr_idx=0;$curr_idx<$#Resource;$curr_idx++) {
+        my $curr_item = $Resource[$curr_idx];
+        if ($granularity eq 'part') {
+            if ($curr_item->{'symb'} eq $target->{'symb'} &&
+                $curr_item->{'part'} eq $target->{'part'}) {
+                last;
+            }
+        } elsif ($granularity eq 'response') {
+            if ($curr_item->{'symb'} eq $target->{'symb'} &&
+                $curr_item->{'part'} eq $target->{'part'} &&
+                $curr_item->{'respid'} eq $target->{'respid'} &&
+                $curr_item->{'resptype'} eq $target->{'resptype'}) {
+                last;
+            }
+        }
+    }
+    my $curr_item = $Resource[$curr_idx];
+    if ($granularity eq 'part') {
+        if ($curr_item->{'symb'}     ne $target->{'symb'} ||
+            $curr_item->{'part'}     ne $target->{'part'}) {
+            # bogus symb - return nothing
+            return (undef,undef,undef);
+        }
+    } elsif ($granularity eq 'response') {
+        if ($curr_item->{'symb'}     ne $target->{'symb'} ||
+            $curr_item->{'part'}     ne $target->{'part'} ||
+            $curr_item->{'respid'}   ne $target->{'respid'} ||
+            $curr_item->{'resptype'} ne $target->{'resptype'}){
+            # bogus symb - return nothing
+            return (undef,undef,undef);
+        }
+    }
+    #
+    # Now just pick up the data we need
+    my ($prev,$curr,$next);
+    if ($curr_idx == 0) {
+        $prev = undef;
+        $curr = $Resource[$curr_idx  ];
+        $next = $Resource[$curr_idx+1];
+    } elsif ($curr_idx == $#Resource) {
+        $prev = $Resource[$curr_idx-1];
+        $curr = $Resource[$curr_idx  ];
+        $next = undef;
+    } else {
+        $prev = $Resource[$curr_idx-1];
+        $curr = $Resource[$curr_idx  ];
+        $next = $Resource[$curr_idx+1];
+    }
+    return ($prev,$curr,$next);
+}
+
+
+#####################################################
+#####################################################
+
+=pod
+
+=item analyze_problem_as_student
+
+Analyzes a homework problem for a student and returns the correct answer
+for the student.  Attempts to put together an answer for problem types 
+that do not natively support it.
+
+Inputs: $resource: a resource object
+        $sname, $sdom, $partid, $respid
+
+Returns: $answer
+
+If $partid and $respid are specified, $answer is simply a scalar containing
+the correct answer for the response.
+
+If $partid or $respid are undefined, $answer will be a hash reference with
+keys $partid.'.'.$respid.'.answer'.
+
+=cut
+
+#####################################################
+#####################################################
+sub analyze_problem_as_student {
+    my ($resource,$sname,$sdom,$partid,$respid) = @_;
+    my $returnvalue;
+    my $url = $resource->{'src'};
+    my $symb = $resource->{'symb'};
+    my $courseid = $ENV{'request.course.id'};
+    my $Answ=&Apache::lonnet::ssi($url,('grade_target' => 'analyze',
+                                        'grade_domain' => $sdom,
+                                        'grade_username' => $sname,
+                                        'grade_symb' => $symb,
+                                        'grade_courseid' => $courseid));
+    (my $garbage,$Answ)=split(/_HASH_REF__/,$Answ,2);
+    my %Answer=&Apache::lonnet::str2hash($Answ);
+    #
+    if (! defined($partid)) {
+        # If you do not specify a partid, you get them all.
+        foreach my $partid (@{$resource->{'parts'}}) {
+            my $partdata = $resource->{'partdata'}->{$partid};
+            foreach my $respid (@{$partdata->{'ResponseIds'}}) {
+                my $prefix = $partid.'.'.$respid;
+                my $key = $prefix.'.answer';
+                $returnvalue->{$key} = &get_answer($prefix,$key,%Answer);
+            }
+        }
+    } elsif (! defined($respid)) {
+        my $partdata = $resource->{'partdata'}->{$partid};
+        foreach my $respid (@{$partdata->{'ResponseIds'}}) {
+            my $prefix = $partid.'.'.$respid;
+            my $key = $prefix.'.answer';
+            $returnvalue->{$key} = &get_answer($prefix,$key,%Answer);
+        }
+    } else {
+        my $prefix = $partid.'.'.$respid;
+        my $key = $prefix.'.answer';
+        $returnvalue = &get_answer($prefix,$key,%Answer);
+    }
+    return $returnvalue;
+}
+
+sub get_answer {
+    my ($prefix,$key,%Answer) = @_;
+    my $returnvalue;
+    if (exists($Answer{$key})) {
+        my $student_answer = $Answer{$key}->[0];
+        if (! defined($student_answer)) {
+            $student_answer = $Answer{$key}->[1];
+        }
+        $returnvalue = $student_answer;
+    } else {
+        if (exists($Answer{$prefix.'.shown'})) {
+            # The response has foils
+            my %values;
+            while (my ($k,$v) = each(%Answer)) {
+                next if ($k !~ /^$prefix\.foil\.(value|area)\.(.*)$/);
+                my $foilname = $2;
+                $values{$foilname}=$v;
+            }
+            foreach my $foil (@{$Answer{$prefix.'.shown'}}) {
+                if (ref($values{$foil}) eq 'ARRAY') {
+                    $returnvalue.=&HTML::Entities::encode($foil).'='.
+                        join(',',map {&HTML::Entities::encode($_)} @{$values{$foil}}).'&';
+                } else {
+                    $returnvalue.=&HTML::Entities::encode($foil).'='.
+                        &HTML::Entities::encode($values{$foil}).'&';
+                }
+            }
+            $returnvalue =~ s/ /\%20/g;
+            chop ($returnvalue);
+        }
+    }
+    return $returnvalue;
+}
+
+##
+## The following is copied from datecalc1.pl, part of the 
+## Spreadsheet::WriteExcel CPAN module.
+##
+##
+######################################################################
+#
+# Demonstration of writing date/time cells to Excel spreadsheets,
+# using UNIX/Perl time as source of date/time.
+#
+# Copyright 2000, Andrew Benham, adsb@bigfoot.com
+#
+######################################################################
+#
+# UNIX/Perl time is the time since the Epoch (00:00:00 GMT, 1 Jan 1970)
+# measured in seconds.
+#
+# An Excel file can use exactly one of two different date/time systems.
+# In these systems, a floating point number represents the number of days
+# (and fractional parts of the day) since a start point. The floating point
+# number is referred to as a 'serial'.
+# The two systems ('1900' and '1904') use different starting points:
+#  '1900'; '1.00' is 1 Jan 1900 BUT 1900 is erroneously regarded as
+#          a leap year - see:
+#            http://support.microsoft.com/support/kb/articles/Q181/3/70.asp
+#          for the excuse^H^H^H^H^H^Hreason.
+#  '1904'; '1.00' is 2 Jan 1904.
+#
+# The '1904' system is the default for Apple Macs. Windows versions of
+# Excel have the option to use the '1904' system.
+#
+# Note that Visual Basic's "DateSerial" function does NOT erroneously
+# regard 1900 as a leap year, and thus its serials do not agree with
+# the 1900 serials of Excel for dates before 1 Mar 1900.
+#
+# Note that StarOffice (at least at version 5.2) does NOT erroneously
+# regard 1900 as a leap year, and thus its serials do not agree with
+# the 1900 serials of Excel for dates before 1 Mar 1900.
+#
+######################################################################
+#
+# Calculation description
+# =======================
+#
+# 1900 system
+# -----------
+# Unix time is '0' at 00:00:00 GMT 1 Jan 1970, i.e. 70 years after 1 Jan 1900.
+# Of those 70 years, 17 (1904,08,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68)
+# were leap years with an extra day.
+# Thus there were 17 + 70*365 days = 25567 days between 1 Jan 1900 and
+# 1 Jan 1970.
+# In the 1900 system, '1' is 1 Jan 1900, but as 1900 was not a leap year
+# 1 Jan 1900 should really be '2', so 1 Jan 1970 is '25569'.
+#
+# 1904 system
+# -----------
+# Unix time is '0' at 00:00:00 GMT 1 Jan 1970, i.e. 66 years after 1 Jan 1904.
+# Of those 66 years, 17 (1904,08,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68)
+# were leap years with an extra day.
+# Thus there were 17 + 66*365 days = 24107 days between 1 Jan 1904 and
+# 1 Jan 1970.
+# In the 1904 system, 2 Jan 1904 being '1', 1 Jan 1970 is '24107'.
+#
+######################################################################
+#
+# Copyright (c) 2000, Andrew Benham.
+# This program is free software. It may be used, redistributed and/or
+# modified under the same terms as Perl itself.
+#
+# Andrew Benham, adsb@bigfoot.com
+# London, United Kingdom
+# 11 Nov 2000
+#
+######################################################################
+#-----------------------------------------------------------
+# calc_serial()
+#
+# Called with (up to) 2 parameters.
+#   1.  Unix timestamp.  If omitted, uses current time.
+#   2.  GMT flag. Set to '1' to return serial in GMT.
+#       If omitted, returns serial in appropriate timezone.
+#
+# Returns date/time serial according to $DATE_SYSTEM selected
+#-----------------------------------------------------------
+sub calc_serial {
+    # Use 1900 date system on all platforms other than Apple Mac (for which
+    # use 1904 date system).
+    my $DATE_SYSTEM = ($^O eq 'MacOS') ? 1 : 0;
+    my $time = (defined $_[0]) ? $_[0] : time();
+    my $gmtflag = (defined $_[1]) ? $_[1] : 0;
+    #
+    # Divide timestamp by number of seconds in a day.
+    # This gives a date serial with '0' on 1 Jan 1970.
+    my $serial = $time / 86400;
+    #
+    # Adjust the date serial by the offset appropriate to the
+    # currently selected system (1900/1904).
+    if ($DATE_SYSTEM == 0) {        # use 1900 system
+        $serial += 25569;
+    } else {                        # use 1904 system
+        $serial += 24107;
+    }
+    #
+    unless ($gmtflag) {
+        # Now have a 'raw' serial with the right offset. But this
+        # gives a serial in GMT, which is false unless the timezone
+        # is GMT. We need to adjust the serial by the appropriate
+        # timezone offset.
+        # Calculate the appropriate timezone offset by seeing what
+        # the differences between localtime and gmtime for the given
+        # time are.
+        #    
+        my @gmtime = gmtime($time);
+        my @ltime  = localtime($time);
+        #
+        # For the first 7 elements of the two arrays, adjust the
+        # date serial where the elements differ.
+        for (0 .. 6) {
+            my $diff = $ltime[$_] - $gmtime[$_];
+            if ($diff) {
+                $serial += _adjustment($diff,$_);
+            }
+        }
+    }
+    #
+    # Perpetuate the error that 1900 was a leap year by decrementing
+    # the serial if we're using the 1900 system and the date is prior to
+    # 1 Mar 1900. This has the effect of making serial value '60'
+    # 29 Feb 1900.
+    #
+    # This fix only has any effect if UNIX/Perl time on the platform
+    # can represent 1900. Many can't.
+    #
+    unless ($DATE_SYSTEM) {
+        $serial-- if ($serial < 61);    # '61' is 1 Mar 1900
+    }
+    return $serial;
+}
+
+sub _adjustment {
+    # Based on the difference in the localtime/gmtime array elements
+    # number, return the adjustment required to the serial.
+    #
+    # We only look at some elements of the localtime/gmtime arrays:
+    #    seconds    unlikely to be different as all known timezones
+    #               have an offset of integral multiples of 15 minutes,
+    #               but it's easy to do.
+    #    minutes    will be different for timezone offsets which are
+    #               not an exact number of hours.
+    #    hours      very likely to be different.
+    #    weekday    will differ when localtime/gmtime difference
+    #               straddles midnight.
+    #
+    # Assume that difference between localtime and gmtime is less than
+    # 5 days, then don't have to do maths for day of month, month number,
+    # year number, etc...
+    #
+    my ($delta,$element) = @_;
+    my $adjust = 0;
+    #
+    if ($element == 0) {            # Seconds
+        $adjust = $delta/86400;         # 60 * 60 * 24
+    } elsif ($element == 1) {       # Minutes
+        $adjust = $delta/1440;          # 60 * 24
+    } elsif ($element == 2) {       # Hours
+        $adjust = $delta/24;            # 24
+    } elsif ($element == 6) {       # Day of week number
+        # Catch difference straddling Sat/Sun in either direction
+        $delta += 7 if ($delta < -4);
+        $delta -= 7 if ($delta > 4);
+        #    
+        $adjust = $delta;
+    }
+    return $adjust;
+}
+
+###########################################################
+###########################################################
+
+=pod
+
+=item get_problem_data
+
+Returns a data structure describing the problem.
+
+Inputs: $url
+
+Returns: %Partdata
+
+=cut
+
+## note: we must force each foil and option to not begin or end with
+##       spaces as they are stored without such data.
+##
+###########################################################
+###########################################################
+sub get_problem_data {
+    my ($url) = @_;
+    my $Answ=&Apache::lonnet::ssi($url,('grade_target' => 'analyze'));
+    (my $garbage,$Answ)=split(/_HASH_REF__/,$Answ,2);
+    my %Answer;
+    %Answer=&Apache::lonnet::str2hash($Answ);
+    my %Partdata;
+    foreach my $part (@{$Answer{'parts'}}) {
+        while (my($key,$value) = each(%Answer)) {
+            #
+            # Logging code:
+            if (1) {
+                &Apache::lonnet::logthis($part.' got key "'.$key.'"');
+                if (ref($value) eq 'ARRAY') {
+                    &Apache::lonnet::logthis('    @'.join(',',@$value));
+                } else {
+                    &Apache::lonnet::logthis('    '.$value);
+                }
+            }
+            # End of logging code
+            next if ($key !~ /^$part/);
+            $key =~ s/^$part\.//;
+            if (ref($value) eq 'ARRAY') {
+                if ($key eq 'options') {
+                    $Partdata{$part}->{'_Options'}=$value;
+                } elsif ($key eq 'concepts') {
+                    $Partdata{$part}->{'_Concepts'}=$value;
+                } elsif ($key =~ /^concept\.(.*)$/) {
+                    my $concept = $1;
+                    foreach my $foil (@$value) {
+                        $Partdata{$part}->{'_Foils'}->{$foil}->{'_Concept'}=
+                                                                      $concept;
+                    }
+                } elsif ($key =~ /^(incorrect|answer|ans_low|ans_high)$/) {
+                    $Partdata{$part}->{$key}=$value;
+                }
+            } else {
+                if ($key=~ /^foil\.text\.(.*)$/) {
+                    my $foil = $1;
+                    $Partdata{$part}->{'_Foils'}->{$foil}->{'name'}=$foil;
+                    $value =~ s/(\s*$|^\s*)//g;
+                    $Partdata{$part}->{'_Foils'}->{$foil}->{'text'}=$value;
+                } elsif ($key =~ /^foil\.value\.(.*)$/) {
+                    my $foil = $1;
+                    $Partdata{$part}->{'_Foils'}->{$foil}->{'value'}=$value;
+                }
+            }
+        }
+    }
+    return %Partdata;
+}
+
+####################################################
+####################################################
+
+=pod
+
+=item &limit_by_time()
+
+=cut
+
+####################################################
+####################################################
+sub limit_by_time_form {
+    my $Starttime_form = '';
+    my $starttime = &Apache::lonhtmlcommon::get_date_from_form
+        ('limitby_startdate');
+    my $endtime = &Apache::lonhtmlcommon::get_date_from_form
+        ('limitby_enddate');
+    if (! defined($endtime)) {
+        $endtime = time;
+    }
+    if (! defined($starttime)) {
+        $starttime = $endtime - 60*60*24*7;
+    }
+    my $state;
+    if (&limit_by_time()) {
+        $state = '';
+    } else {
+        $state = 'disabled';
+    }
+    my $startdateform = &Apache::lonhtmlcommon::date_setter
+        ('Statistics','limitby_startdate',$starttime,undef,undef,$state);
+    my $enddateform = &Apache::lonhtmlcommon::date_setter
+        ('Statistics','limitby_enddate',$endtime,undef,undef,$state);
+    my $Str;
+    $Str .= '<script language="Javascript" >';
+    $Str .= 'function toggle_limitby_activity(state) {';
+    $Str .= '    if (state) {';
+    $Str .= '        limitby_startdate_enable();';
+    $Str .= '        limitby_enddate_enable();';
+    $Str .= '    } else {';
+    $Str .= '        limitby_startdate_disable();';
+    $Str .= '        limitby_enddate_disable();';
+    $Str .= '    }';    
+    $Str .= '}';
+    $Str .= '</script>';
+    $Str .= '<fieldset>';
+    my $timecheckbox = '<input type="checkbox" name="limit_by_time" ';
+    if (&limit_by_time()) {
+        $timecheckbox .= ' checked ';
+    } 
+    $timecheckbox .= 'OnChange="javascript:toggle_limitby_activity(this.checked);" ';
+    $timecheckbox .= ' />';
+    $Str .= '<legend>'.&mt('[_1] Limit by time',$timecheckbox).'</legend>';
+    $Str .= &mt('Start Time: [_1]',$startdateform).'<br />';
+    $Str .= &mt('&nbsp;End Time: [_1]',$enddateform).'<br />';
+    $Str .= '</fieldset>';
+    return $Str;
+}
+
+sub limit_by_time {
+    if (exists($ENV{'form.limit_by_time'}) &&
+        $ENV{'form.limit_by_time'} ne '' ) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+sub get_time_limits {
+    my $starttime = &Apache::lonhtmlcommon::get_date_from_form
+        ('limitby_startdate');
+    my $endtime = &Apache::lonhtmlcommon::get_date_from_form
+        ('limitby_enddate');
+    return ($starttime,$endtime);
+}
+
+####################################################
+####################################################
+
+=pod
+
+=back
+
+=cut
+
+####################################################
+####################################################
+
 1;
 
 __END__