File:  [LON-CAPA] / loncom / homework / response.pm
Revision 1.248: download - view: text, annotated - select for diffs
Tue Jan 12 15:52:06 2021 UTC (16 months, 1 week ago) by raeburn
Branches: MAIN
CVS tags: version_2_12_X, HEAD
- If questiontype in effect is one of the four survey types, and award on submission
  for a customresponse item is 'ASSIGNED_SCORE', change that to one of:
  SUBMITTED, SUBMITTED_CREDIT, ANONYMOUS or ANONYMOUS_CREDIT, as appropriate.

# The LearningOnline Network with CAPA
# various response type definitons response definition
#
# $Id: response.pm,v 1.248 2021/01/12 15:52:06 raeburn 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/
#

=pod

=head1 NAME

Apache::response.pm

=head1 SYNOPSIS

This is part of the LearningOnline Network with CAPA project
described at http://www.lon-capa.org.


=head1 NOTABLE SUBROUTINES

=over

=item 

=back

=cut


package Apache::response;
use strict;
use Apache::lonlocal;
use Apache::lonnet;
use Apache::inputtags();
use Apache::lonmaxima();
use Apache::lonr();
use Apache::lontexconvert();

BEGIN {
    &Apache::lonxml::register('Apache::response',('responseparam','parameter','dataresponse','customresponse','mathresponse'));
}

sub start_response {
    my ($parstack,$safeeval)=@_;
    my $id = &Apache::lonxml::get_id($parstack,$safeeval);
    if ($#Apache::inputtags::import > -1) {
	&Apache::lonxml::debug("Turning :$id: into");
	$id = join('_',@Apache::inputtags::import).'_'.$id;
	&Apache::lonxml::debug("New  :$id:");
    }
    push (@Apache::inputtags::response,$id);
    push (@Apache::inputtags::responselist,$id);
    @Apache::inputtags::inputlist=();
    if ($Apache::inputtags::part eq '' && 
	!$Apache::lonhomework::ignore_response_errors) {
	&Apache::lonxml::error(&HTML::Entities::encode(&mt("Found a <*response> outside of a <part> in a <part>ed problem"),'<>&"'));
    }
    if ($Apache::inputtags::response_with_no_part &&
	$Apache::inputtags::part ne '0') {
	&Apache::lonxml::error(&HTML::Entities::encode(&mt("<*response>s are both inside of <part> and outside of <part>, this is not a valid problem, errors in grading may occur."),'<>&"').'<br />');
    }
    if ($Apache::inputtags::part eq '0') {
	$Apache::inputtags::response_with_no_part=1;
    }
    return $id;
}

sub end_response {
    #pop @Apache::inputtags::response;
    @Apache::inputtags::inputlist=();
    return '';
}

sub start_hintresponse {
    my ($parstack,$safeeval)=@_;
    my $id = &Apache::lonxml::get_id($parstack,$safeeval);
    push (@Apache::inputtags::hint,$id);
    push (@Apache::inputtags::hintlist,$id);
    push (@Apache::inputtags::paramstack,[%Apache::inputtags::params]);
    return $id;
}

sub end_hintresponse {
    pop @Apache::inputtags::hint;
    if (defined($Apache::inputtags::paramstack[-1])) {
	%Apache::inputtags::params=
	    @{ pop(@Apache::inputtags::paramstack) };
    }
    return '';
}

my @randomseeds;
sub pushrandomnumber {
    my $rand_alg=&Apache::lonnet::get_rand_alg();
    if (!$rand_alg || $rand_alg eq '32bit' || $rand_alg eq '64bit' ||
	$rand_alg eq '64bit2') {
	# do nothing
    } else {
	my @seed=&Math::Random::random_get_seed();
	push(@randomseeds,\@seed);
    }
    &Apache::response::setrandomnumber(@_);
}
sub poprandomnumber {
    my $rand_alg=&Apache::lonnet::get_rand_alg();
    if (!$rand_alg || $rand_alg eq '32bit' || $rand_alg eq '64bit' ||
	$rand_alg eq '64bit2') {
	return;
    }
    my $seed=pop(@randomseeds);
    if ($seed) {
	&Math::Random::random_set_seed(@$seed);
    } else {
	&Apache::lonxml::error("Unable to restore random algorithm.");
    }
}

sub setrandomnumber {
    my ($ignore_id2,$target,$rndseed) = @_;
    if (!defined($rndseed)) {
        $rndseed=&Apache::structuretags::setup_rndseed(undef,$target);
    } 
    if (!defined($rndseed)) { $rndseed=&Apache::lonnet::rndseed(); }
    &Apache::lonxml::debug("randseed $rndseed");
    #  $rndseed=unpack("%32i",$rndseed);
    my $rand_alg=&Apache::lonnet::get_rand_alg();
    my ($rndmod,$rndmod2);

    my ($id1,$id2,$shift_amt);
    if ($Apache::lonhomework::parsing_a_problem) {
	$id1=$Apache::inputtags::part;
	if (defined($Apache::inputtags::response[-1])) {
	    $id2=$Apache::inputtags::response[-1];
	}
	$shift_amt=scalar(@Apache::inputtags::responselist);
    } elsif ($Apache::lonhomework::parsing_a_task) {
	$id1=&Apache::bridgetask::get_dim_id();
	if (!$ignore_id2 && ref($Apache::bridgetask::instance{$id1})) {
	    $id2=$Apache::bridgetask::instance{$id1}[-1];
	    $shift_amt=scalar(@{$Apache::bridgetask::instance{$id1}});
	} else {
	    $shift_amt=0;
	}
    } 
    &Apache::lonxml::debug("id1: $id1, id2: $id2, shift_amt: $shift_amt");
    if (!$rand_alg || $rand_alg eq '32bit' || $rand_alg eq '64bit' ||
	$rand_alg eq '64bit2') {
	$rndmod=(&Apache::lonnet::numval($id1) << 10);
	if (defined($id2)) { $rndmod+=&Apache::lonnet::numval($id2); }
    } elsif ($rand_alg eq '64bit3') {
	$rndmod=(&Apache::lonnet::numval2($id1) << 10);
	if (defined($id2)) { $rndmod+=&Apache::lonnet::numval2($id2); }
    } elsif ($rand_alg eq '64bit4') {
	my $shift=(4*$shift_amt)%30;
	$rndmod=(&Apache::lonnet::numval3($id1) << (($shift+15)%30));
	if (defined($id2)) {
	    $rndmod+=(&Apache::lonnet::numval3($id2) << $shift );
	}
    } else {
	($rndmod,$rndmod2)=&Apache::lonnet::digest("$id1,$id2");
    }
    if ($rndseed =~/([,:])/) {
	my $char=$1;
	use integer;
	my ($num1,$num2)=split(/\Q$char\E/,$rndseed);
	$num1+=$rndmod;
	$num2+= ((defined($rndmod2)) ? $rndmod2 : $rndmod);
	if($Apache::lonnet::_64bit) { $num1=(($num1<<32)>>32); $num2=(($num2<<32)>>32); }
	$rndseed=$num1.$char.$num2;
    } else {
	$rndseed+=$rndmod;
	if($Apache::lonnet::_64bit) {
	    use integer;
	    $rndseed=(($rndseed<<32)>>32);
	}
    }
    &Apache::lonxml::debug("randseed $rndmod $rndseed");
    &Apache::lonnet::setup_random_from_rndseed($rndseed);
    return '';
}

sub meta_parameter_write {
    my ($name,$type,$default,$display)=@_;
    my $partref=$Apache::inputtags::part;
    my $result='<parameter part="'.$Apache::inputtags::part.'"';
    if (defined($Apache::inputtags::response[-1])) {
	$result.=            ' id="'.$Apache::inputtags::response[-1].'"';
	$partref.='_'.$Apache::inputtags::response[-1];
    }
    $result.=            ' name="'.$name.'"'.
                         ' type="'.$type.'"'.
(defined($default)?' default="'.$default.'"':'').
(defined($display)?' display="'.$display.' [Part: '.$partref.']"':'')
             .'></parameter>'
             ."\n";
    return $result;
}

sub meta_package_write {
    my $name=shift;
    my $result = '<parameter part="'.$Apache::inputtags::part.'"';
    if(defined($Apache::inputtags::response[-1])) {
	$result.= ' id="'.$Apache::inputtags::response[-1].'"';
    }
    $result.=' package="'.$name.'"></parameter>'."\n";
    return $result;
}

sub meta_stores_write {
    my ($name,$type,$display)=@_;
    my $partref=$Apache::inputtags::part;
    my $result = '<stores part="'.$Apache::inputtags::part.'"';
    if (defined($Apache::inputtags::response[-1])) {
	$result.=           ' id="'.$Apache::inputtags::response[-1].'"';
	$partref.='_'.$Apache::inputtags::response[-1];
    }	
    $result.=          ' name="'.$name.'"'.
                       ' type="'.$type.'"'.
	            ' display="'.$display.' [Part: '.$partref.']"'.
		      "></stores>\n";
}

=pod

=item mandatory_part_meta()

Autogenerate metadata for mandatory
input (from RAT or lonparmset) and
output (to lonspreadsheet)
of each part

Note: responseid-specific data 'submission' and 'awarddetail'
not available to spreadsheet -> skip here

=cut


sub mandatory_part_meta {
    return &meta_package_write('part').
           &meta_stores_write('solved','string','Problem Status').
           &meta_stores_write('tries','int_zeropos','Number of Attempts').
           &meta_stores_write('awarded','float','Partial Credit Factor');
}

sub meta_part_order {
    my ($type) = @_; 
    if (@Apache::inputtags::partlist) {
	my @parts=@Apache::inputtags::partlist;
        unless ($type eq 'library') {
	    shift(@parts);
        }
	return '<partorder>'.join(',',@parts).'</partorder>'."\n";
    } elsif ($type eq 'library') {
        return '<partorder></partorder>'."\n";
    } else {
	return '<partorder>0</partorder>'."\n";
    }
}

sub meta_response_order {
    if (@Apache::inputtags::responselist) {
	return '<responseorder>'.join(',',@Apache::inputtags::responselist).
	    '</responseorder>'."\n";
    }
}

sub check_for_previous {
    my ($curresponse,$partid,$id,$last,$type) = @_;
    my %previous;
    $previous{'used'} = 0;
    my $questiontype = $Apache::lonhomework::type;
    my $curr_rndseed = $env{'form.'.$partid.'.rndseed'};
    foreach my $key (sort(keys(%Apache::lonhomework::history))) {
	if ($key =~ /resource\.\Q$partid\E\.\Q$id\E\.submission$/) {
	    if ( $last && $key =~ /^(\d+):/ ) {
		next if ($1 >= $last);
	    }
	    &Apache::lonxml::debug("Trying $key");
	    my $pastresponse=$Apache::lonhomework::history{$key};
	    if ($pastresponse eq $curresponse) {
		my $history;
		if ( $key =~ /^(\d+):/ ) {
                    $history=$1;
                    next if ((($questiontype eq 'randomizetry') ||
                             ($Apache::lonhomework::history{"$history:resource.$partid.type"} eq 'randomizetry')) &&
                             ($curr_rndseed ne $Apache::lonhomework::history{"$history:resource.$partid.rndseed"}));
		    $previous{'award'} = $Apache::lonhomework::history{"$history:resource.$partid.$id.awarddetail"};
		    $previous{'last'}='0';
		    push(@{ $previous{'version'} },$history);
		} else {
                    next if ((($questiontype eq 'randomizetry') ||
                             ($Apache::lonhomework::history{"resource.$partid.type"} eq 'randomizetry')) &&
                             ($curr_rndseed ne $Apache::lonhomework::history{"resource.$partid.rndseed"}));
		    $previous{'award'} = $Apache::lonhomework::history{"resource.$partid.$id.awarddetail"};
		    $previous{'last'}='1';
		}
                $previous{'used'} = 1;
		if (! $previous{'award'} ) { $previous{'award'} = 'UNKNOWN';	}
                if ($previous{'award'} eq 'INTERNAL_ERROR') { $previous{'used'}=0; }
		&Apache::lonxml::debug("got a match :$previous{'award'}:$previous{'used'}:");
            } elsif ($type eq 'ci') {
                if (lc($pastresponse) eq lc($curresponse)) {
                    if ($key =~ /^(\d+):/) {
                        my $history = $1;
                        next if (($questiontype eq 'randomizetry') &&
                             ($curr_rndseed ne $Apache::lonhomework::history{"$history:resource.$partid.rndseed"}));
                        push (@{$previous{'versionci'}},$history);
                        $previous{'awardci'} = $Apache::lonhomework::history{"$history:resource.$partid.$id.awarddetail"};
                        $previous{'usedci'} = 1;
                    }
                }
            }
	}
    }
    &Apache::lonhomework::showhash(%previous);
    return %previous;
}

sub handle_previous {
    my ($previous,$ad)=@_;
    if ($$previous{'used'} && ($$previous{'award'} eq $ad) ) {
	if ($$previous{'last'}) {
	    push(@Apache::inputtags::previous,'PREVIOUSLY_LAST');
	    push(@Apache::inputtags::previous_version,$$previous{'version'});
	} elsif (($Apache::lonhomework::type ne 'survey') &&
                 ($Apache::lonhomework::type ne 'surveycred') &&
                 ($Apache::lonhomework::type ne 'anonsurvey') &&
                 ($Apache::lonhomework::type ne 'anonsurveycred')) {
	    push(@Apache::inputtags::previous,'PREVIOUSLY_USED');
	    push(@Apache::inputtags::previous_version,$$previous{'version'});
	}
    }
}

sub view_or_modify {
    my ($symb,$courseid,$domain,$name) = &Apache::lonnet::whichuser();
    my $myself=0;
    if ( ($name eq $env{'user.name'}) && ($domain eq $env{'user.domain'}) ) {
	$myself=1;
    }
    my $vgr=&Apache::lonnet::allowed('vgr',$courseid);
    my $mgr=&Apache::lonnet::allowed('vgr',$courseid);
    if ($mgr) { return "M"; }
    if ($vgr) { return "V"; }
    if ($myself) { return "V"; }
    return '';
}

sub start_dataresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $id = &Apache::response::start_response($parstack,$safeeval);
    my $result;
    if ($target eq 'web') {
	$result = $token->[2]->{'display'}.':';
    } elsif ($target eq 'meta') {
	$result = &Apache::response::meta_stores_write($token->[2]->{'name'},
						       $token->[2]->{'type'},
						       $token->[2]->{'display'});
	$result .= &Apache::response::meta_package_write('dataresponse');
    }
    return $result;
}

sub end_dataresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    if ( $target eq 'web' ) {
    } elsif ($target eq 'grade' ) {
	if ( defined $env{'form.submitted'}) {
	    my ($symb,$courseid,$domain,$name)=&Apache::lonnet::whichuser();
	    my $allowed=&Apache::lonnet::allowed('mgr',$courseid);
	    if ($allowed) {
		&Apache::response::setup_params('dataresponse',$safeeval);
		my $partid = $Apache::inputtags::part;
		my $id = $Apache::inputtags::response['-1'];
		my $response = $env{'form.HWVAL_'.$id};
		my $name = &Apache::lonxml::get_param('name',$parstack,$safeeval);
		if ( $response =~ /[^\s]/) {
		    $Apache::lonhomework::results{"resource.$partid.$id.$name"}=$response;
		    $Apache::lonhomework::results{"resource.$partid.$id.submission"}=$response;
		    $Apache::lonhomework::results{"resource.$partid.$id.awarddetail"}='SUBMITTED';
		}
	    } else {
                $result=&mt('Not Permitted to change values');
	    }
	}
    }
    &Apache::response::end_response;
    return $result;
}

sub start_customresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $id = &Apache::response::start_response($parstack,$safeeval);
    push(@Apache::lonxml::namespace,'customresponse');
    my $result;
    @Apache::response::custom_answer=();
    @Apache::response::custom_answer_type=();
    &Apache::lonxml::register('Apache::response',('answer'));
    if ($target eq 'web') {
  	if (  &Apache::response::show_answer() ) {
	    my $answer = &Apache::lonxml::get_param('answerdisplay',$parstack,
						   $safeeval);
	    $Apache::inputtags::answertxt{$id}=[$answer];
	}
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token);
	$result.=&Apache::edit::text_arg('String to display for answer:',
					 'answerdisplay',$token,'50');
	$result.=&Apache::edit::end_row().&Apache::edit::start_spanning_row();
    } elsif ($target eq 'modified') {
	my $constructtag;
	$constructtag=&Apache::edit::get_new_args($token,$parstack,
						  $safeeval,'answerdisplay');
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    } elsif ($target eq 'answer' || $target eq 'grade') {
	&Apache::response::reset_params();
    } elsif ($target eq 'meta') {
	$result .= &Apache::response::meta_package_write('customresponse');
    }
    return $result;
}

sub end_customresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    my $part=$Apache::inputtags::part;
    my $id=$Apache::inputtags::response[-1];
    if ( $target eq 'grade' && &Apache::response::submitted() ) {
	my $response = &Apache::response::getresponse();
	if ($Apache::lonhomework::type eq 'exam' ||
	    &Apache::response::submitted('scantron')) {
	    &Apache::response::scored_response($part,$id);
	} elsif ( $response =~ /[^\s]/ && 
		  $Apache::response::custom_answer_type[-1] eq 'loncapa/perl') {
	    if (!$Apache::lonxml::default_homework_loaded) {
		&Apache::lonxml::default_homework_load($safeeval);
	    }
	    my %previous = &Apache::response::check_for_previous($response,
								 $part,$id);
	    $Apache::lonhomework::results{"resource.$part.$id.submission"}=
		$response;
	    my $error;
	    ${$safeeval->varglob('LONCAPA::customresponse_submission')}=
		$response;
	    
	    my ($award,$score) = &Apache::run::run('{ my $submission=$LONCAPA::customresponse_submission;'.$Apache::response::custom_answer[-1].'}',$safeeval);
	    if (!&Apache::inputtags::valid_award($award)) {
		$error = $award;
		$award = 'ERROR';
	    }
            if (($award eq 'INCORRECT') || ($award eq 'APPROX_ANS') ||
                ($award eq 'EXACT_ANS') || ($award eq 'ASSIGNED_SCORE')) {
                if ($Apache::lonhomework::type eq 'survey') {
                    $award='SUBMITTED';
                } elsif ($Apache::lonhomework::type eq 'surveycred') {
                    $award='SUBMITTED_CREDIT';
                } elsif ($Apache::lonhomework::type eq 'anonsurvey') {
                    $award='ANONYMOUS';
                } elsif ($Apache::lonhomework::type eq 'anonsurveycred') {
                    $award='ANONYMOUS_CREDIT';
                }
            }
	    &Apache::response::handle_previous(\%previous,$award);
	    $Apache::lonhomework::results{"resource.$part.$id.awarddetail"}=
		$award;
            if ($award eq 'ASSIGNED_SCORE') {
                $Apache::lonhomework::results{"resource.$part.$id.awarded"}=1.0*$score;
            }
	    if ($error) {
		$Apache::lonhomework::results{"resource.$part.$id.awardmsg"}=
		    $error;
	    }
	}
    } elsif ( $target eq 'answer') {
	$result  = &Apache::response::answer_header('customresponse');
	my $answer = &Apache::lonxml::get_param('answerdisplay',$parstack,
						$safeeval);
	if ($env{'form.answer_output_mode'} ne 'tex') {
	    $answer = '<b>'.$answer.'</b>';
	}
	$result .= &Apache::response::answer_part('customresponse',$answer);
	$result .= &Apache::response::answer_footer('customresponse');
    }
    if ($target eq 'web') {
	&setup_prior_tries_hash(\&format_prior_response_custom);
    }
    if ($target eq 'grade' || $target eq 'web' || $target eq 'answer' || 
	$target eq 'tex' || $target eq 'analyze') {
        my $repetition = &repetition();
	&Apache::lonxml::increment_counter($repetition,"$part.$id");
	if ($target eq 'analyze') {
            $Apache::lonhomework::analyze{"$part.$id.type"} = 'customresponse';
	    &Apache::lonhomework::set_bubble_lines();
	}
    }
    if ($target eq 'web') {
        &setup_prior_tries_hash(\&format_prior_response_math);
    }
    pop(@Apache::lonxml::namespace);
    pop(@Apache::response::custom_answer);
    pop(@Apache::response::custom_answer_type);
    &Apache::lonxml::deregister('Apache::response',('answer'));
    &Apache::response::end_response();
    return $result;
}

sub format_prior_response_custom {
    my ($mode,$answer) =@_;
    if (ref($answer) eq 'ARRAY') {
        $answer = '('.join(', ', @{ $answer }).')';
    }
    return '<span class="LC_prior_custom">'.
	    &HTML::Entities::encode($answer,'"<>&').'</span>';
}

sub start_mathresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $id = &Apache::response::start_response($parstack,$safeeval);
    push(@Apache::lonxml::namespace,'mathresponse');
    my $result;
    @Apache::response::custom_answer=();
    @Apache::response::custom_answer_type=();
    &Apache::lonxml::register('Apache::response',('answer'));
    if ($target eq 'web') {
  	if (  &Apache::response::show_answer() ) {
	    my $answer = &Apache::lonxml::get_param('answerdisplay',$parstack,
						   $safeeval);
	    $Apache::inputtags::answertxt{$id}=[$answer];
	}

    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token);
	$result.=&Apache::edit::text_arg('String to display for answer:',
					 'answerdisplay',$token,'50');
	$result.=&Apache::edit::select_arg('Algebra System:',
					   'cas',
					   ['maxima','R'],
					   $token);
	$result.=&Apache::edit::text_arg('Argument Array:',
					 'args',$token).
                 &Apache::loncommon::help_open_topic('Maxima_Argument_Array');
        $result.=&Apache::edit::text_arg('Libraries:',
                                         'libraries',$token).
                 &Apache::loncommon::help_open_topic('Maxima_Libraries');
	$result.=&Apache::edit::end_row().&Apache::edit::start_spanning_row();
    } elsif ($target eq 'modified') {
	my $constructtag;
	$constructtag=&Apache::edit::get_new_args($token,$parstack,
						  $safeeval,'answerdisplay','cas','args','libraries');
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    } elsif ($target eq 'answer' || $target eq 'grade') {
	&Apache::response::reset_params();
    } elsif ($target eq 'meta') {
	$result .= &Apache::response::meta_package_write('mathresponse');
    }
    return $result;
}

sub end_mathresponse {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    my $part=$Apache::inputtags::part;
    my $id=$Apache::inputtags::response[-1];
    if ( $target eq 'grade' && &Apache::response::submitted() ) {
	my $response = &Apache::response::getresponse();
	if ( $response =~ /[^\s]/ ) {
	    if (!$Apache::lonxml::default_homework_loaded) {
		&Apache::lonxml::default_homework_load($safeeval);
	    }
	    my %previous = &Apache::response::check_for_previous($response,
								 $part,$id);
	    $Apache::lonhomework::results{"resource.$part.$id.submission"}=
		$response;
	    my $error;
	    my $award;
	    my $cas = &Apache::lonxml::get_param('cas',$parstack,$safeeval);
            if ($cas eq 'maxima') {
                my $args = [&Apache::lonxml::get_param_var('args',$parstack,$safeeval)];
                $award=&Apache::lonmaxima::maxima_run($Apache::response::custom_answer[-1],$response,$args,
                                                      &Apache::lonxml::get_param('libraries',$parstack,$safeeval));
            }
            if ($cas eq 'R') {
                my $args = [&Apache::lonxml::get_param_var('args',$parstack,$safeeval)];
                $award=&Apache::lonr::r_run($Apache::response::custom_answer[-1],$response,$args,
                                            &Apache::lonxml::get_param('libraries',$parstack,$safeeval));
            }

	    if (!&Apache::inputtags::valid_award($award)) {
		$error = $award;
		$award = 'ERROR';
	    }
            if (($award eq 'INCORRECT' || $award eq 'APPROX_ANS' ||
                 $award eq 'EXACT_ANS')) {
                if ($Apache::lonhomework::type eq 'survey') {
                    $award='SUBMITTED';
                } elsif ($Apache::lonhomework::type eq 'surveycred') {
                    $award='SUBMITTED_CREDIT';
                } elsif ($Apache::lonhomework::type eq 'anonsurvey') {
                    $award='ANONYMOUS';
                } elsif ($Apache::lonhomework::type eq 'anonsurveycred') {
                    $award='ANONYMOUS_CREDIT';
                }
            }
	    &Apache::response::handle_previous(\%previous,$award);
	    $Apache::lonhomework::results{"resource.$part.$id.awarddetail"}=
		$award;
	    if ($error) {
		$Apache::lonhomework::results{"resource.$part.$id.awardmsg"}=
		    $error;
	    }
	}
    }

    pop(@Apache::lonxml::namespace);
    pop(@Apache::response::custom_answer);
    pop(@Apache::response::custom_answer_type);
    &Apache::lonxml::deregister('Apache::response',('answer'));
    &Apache::response::end_response();
    return $result;
}

sub format_prior_response_math {
    my ($mode,$answer) =@_;
    return '<span class="LC_prior_math">'.
	    &HTML::Entities::encode($answer,'"<>&').'</span>';
}

sub implicit_multiplication {
    my ($expression)=@_;
# Escape scientific notation, so 3e8 does not become 3*e*8
# 3e8 -> 3&8; 3e-8 -> 3&-8; 3E+8 -> e&+8
    $expression=~s/(\d+)e([\+\-]*\d+)/$1\&\($2\)/gsi;
# 3x10^8 -> 3&8; 3*10^-8 -> 3&-8
    $expression=~s/(\d+)(?:x|\*)10(?:\^|\*\*)([\+\-]*\d+)/$1\&\($2\)/gsi;
# Fill in multiplication signs
# a b -> a*b;3 b -> 3*b;3 4 -> 3*4
    $expression=~s/([A-Za-z0-9])\s+(?=[A-Za-z0-9])/$1\*/gs;
# )( -> )*(; ) ( -> )*(
    $expression=~s/\)\s*\(/\)\*\(/gs;
# 3a -> 3*a; 3( -> 3*(; 3 ( -> 3*(; 3A -> 3*A
    $expression=~s/(\d)\s*([a-zA-Z\(])/$1\*$2/gs;
# a ( -> a*(
    $expression=~s/([A-Za-z0-9])\s+\(/$1\*\(/gs;
# )a -> )*a; )3 -> )*3; ) 3 -> )*3
    $expression=~s/\)\s*([A-Za-z0-9])/\)\*$1/gs;
# 3&8 -> 3e8; 3&-4 -> 3e-4
    $expression=~s/(\d+)\&\(([\+\-]*\d+)\)/$1e$2/gs;
    return $expression;
}

sub start_answer {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    push(@Apache::response::custom_answer,
	&Apache::lonxml::get_all_text_unbalanced("/answer",$parser));
    push(@Apache::response::custom_answer_type,
	lc(&Apache::lonxml::get_param('type',$parstack,$safeeval)));
    $Apache::response::custom_answer_type[-1] =~ s/\s+//g;
    if ($target eq "edit" ) {
	$result=&Apache::edit::tag_start($target,$token,'Answer algorithm');
	$result.=&Apache::edit::editfield($token->[1],
					  $Apache::response::custom_answer[-1],
					  '',80,4);
    } elsif ( $target eq "modified" ) {
	$result=$token->[4].&Apache::edit::modifiedfield('/answer',$parser);
    }
    return $result;
}

sub end_answer {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    if ($target eq 'edit' ) {
	return &Apache::edit::end_table();
    }
}

sub decide_package {
    my ($tagstack)=@_;
    my $package;
    if ($$tagstack[-1] eq 'parameter') {
	$package='part';
    } else {
	my $i=-1;
	while (defined($$tagstack[$i])) {
	    if ($$tagstack[$i] =~ /(response|hint)$/) {
		$package=$$tagstack[$i];
		last;
	    }
	    $i--;
	}
    }
    return $package;
}

sub start_responseparam {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result='';
    if ($target eq 'meta') {
	$result = &meta_parameter_write($token->[2]->{'name'},
					$token->[2]->{'type'},
					$token->[2]->{'default'},
					$token->[2]->{'description'});
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token);
	my $optionlist;
	my $package=&decide_package($tagstack);
	foreach my $key (sort(keys(%Apache::lonnet::packagetab))) {
	    if ($key =~ /^\Q$package\E&(.*)&display$/) {
		$optionlist.='<option value="'.$1.'">'.
		    $Apache::lonnet::packagetab{$key}.'</option>';
	    }
	}
	if (defined($optionlist)) {
	    $result.=&mt('Use template:').' <select name="'.
		&Apache::edit::html_element_name('parameter_package').'">'.
		    '<option value=""></option>'.$optionlist.'</select><br />';
	}
	$result.=&Apache::edit::text_arg('Name:','name',$token).
	    &Apache::edit::text_arg('Type:','type',$token).
		&Apache::edit::text_arg('Description:','description',$token).
		    &Apache::edit::text_arg('Default:','default',$token).
			"</td></tr>";
	$result.=&Apache::edit::end_table;
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args($token,$parstack,
						     $safeeval,'name','type',
						     'description','default');
	my $element=&Apache::edit::html_element_name('parameter_package');
	if (defined($env{"form.$element"}) && $env{"form.$element"} ne '') {
	    my $name=$env{"form.$element"};
	    my $tag=&decide_package($tagstack);
	    $token->[2]->{'name'}=$name;
	    $token->[2]->{'type'}=
		$Apache::lonnet::packagetab{"$tag&$name&type"};
	    $token->[2]->{'description'}=
		$Apache::lonnet::packagetab{"$tag&$name&display"};
	    $token->[2]->{'default'}=
		$Apache::lonnet::packagetab{"$tag&$name&default"};
            $token->[3] = ['name','type','description','default'];
	    $constructtag=1;
	}
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    } elsif ($target eq 'grade' || $target eq 'answer' || $target eq 'web' ||
	     $target eq 'tex' || $target eq 'analyze' ) {
	if ($env{'request.state'} eq 'construct') {
	    my $name   =&Apache::lonxml::get_param('name',$parstack,$safeeval);
	    my $default=&Apache::lonxml::get_param('default',$parstack,
						     $safeeval);
	    if ($name) {$Apache::inputtags::params{$name}=$default;}
	}
    }
    return $result;
}

sub end_responseparam {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    if ($target eq 'edit') { return ('','no'); }
    return '';
}

sub start_parameter {
    return &start_responseparam(@_);
}

sub end_parameter {
    return &end_responseparam(@_);
}

sub reset_params {
    %Apache::inputtags::params=();
}

sub setup_params {
    my ($tag,$safeeval) = @_;

    if ($env{'request.state'} eq 'construct') { return; }
    my %paramlist=();
    foreach my $key (keys(%Apache::lonnet::packagetab)) {
	if ($key =~ /^\Q$tag\E/) {
	    my ($package,$name) = split(/&/,$key);
	    $paramlist{$name}=1;
	}
    }
    foreach my $key (keys(%paramlist)) {
	my $entry= 'resource.'.$Apache::inputtags::part;
	if (defined($Apache::inputtags::response[-1])) {
	    $entry.='_'.$Apache::inputtags::response[-1];
	}
	$entry.='.'.$key;
	&Apache::lonxml::debug("looking for $entry");
	my $value = &Apache::lonnet::EXT("$entry");
	&Apache::lonxml::debug("$key has value :$value:");
	if ($value eq 'con_lost' || $value =~ /^error:/) {
	    &Apache::lonxml::debug("using nothing");
	    $Apache::inputtags::params{$key}='';
	} else {
	    my $string="{return qq\0".$value."\0}";
	    my $newvalue=&Apache::run::run($string,$safeeval,1);
	    if (defined($newvalue)) { $value=$newvalue; }
	    $Apache::inputtags::params{$key}=$value;
	}
    }
}

{
    my @answer_bits;
    my $need_row_start;

sub answer_header {
    my ($type,$increment,$rows) = @_;
    my $result;
    if ($env{'form.answer_output_mode'} eq 'tex') {
	undef(@answer_bits);
	my $bit;
	if ($Apache::lonhomework::type eq 'exam') {
	    $bit = ($Apache::lonxml::counter+$increment).') ';
	} else {
            $bit .= ' '.&mt('Answer for Part: [_1]',
                                '\verb|'.$Apache::inputtags::part.'|').' ';
	}
	push(@answer_bits,$bit);
    } else {
	my $td = '<td '.(defined($rows)?'rowspan="'.$rows.'"':'').'>';
	$result  = '<table border="1"><tr>';
	if ($Apache::lonhomework::type eq 'exam') {
	    $result .= $td.($Apache::lonxml::counter+$increment). ')</td>';
	} else {
	    $result .= $td.&mt('Answer for Part: [_1]',
			       $Apache::inputtags::part).'</td>';
	}
	$result .= "\n";
	$need_row_start = 0;
    }
    return $result;
}

sub next_answer {
    my ($type) = @_;
    my $result;
    if ($env{'form.answer_output_mode'} eq 'tex') {
	# FIXME ... need to do something with tex mode
    } else {
	$result .= "</tr>";
	$need_row_start = 1;
    }
    return $result;
}

sub answer_part {
    my ($type,$answer,$args) = @_;
    my $result;
    if ($env{'form.answer_output_mode'} eq 'tex') {
	if (!$args->{'no_verbatim'}) {
	    my $to_use='|';
	    foreach my $value (32..126) {
		my $char=pack('c',$value);
		if ($answer !~ /\Q$char\E/) {
		    $to_use=$char;
		    last;
		}
	    }
            my $fullanswer=$answer;
            $answer='';
            foreach my $element (split(/[\;]/,$fullanswer)) {
	       if ($element ne '') {
	 	  $answer.= '\verb'.$to_use.$element.$to_use.' \newline';
	       }
            }
	}
	if ($answer ne '') {
	    push(@answer_bits,$answer);
	}
    } else {
	if ($need_row_start) {
	    $result .= '<tr>';
	    $need_row_start = 0;
	}
	$result .= '<td>'.$answer.'</td>';
    }
    return $result;
}

sub answer_footer {
    my ($type) = @_;
    my $result;
    if ($env{'form.answer_output_mode'} eq 'tex') {
	$result  = ' \vskip 0 mm \noindent \begin{tabular}{|p{1.5cm}|p{6.8cm}|}\hline ';
	$result .= $answer_bits[0].'&\vspace*{-4mm}\begin{itemize}';
        for (my $i=1;$i<=$#answer_bits;$i++) {
            $result.='\item '.$answer_bits[$i].'\vspace*{-7mm}';
        }
	$result .= ' \end{itemize} \\\\ \hline \end{tabular} \vskip 0 mm ';
    } else {
	if (!$need_row_start) {
	    $result .= '</tr>';
	}
	$result .= '</table>';
    }
    return $result;
}

}

sub showallfoils {
    if (defined($env{'form.showallfoils'})) {
	my ($symb)=&Apache::lonnet::whichuser();
	if (($env{'request.state'} eq 'construct') || 
	    ($env{'user.adv'} && $symb eq '')      ||
            ($Apache::lonhomework::viewgrades) ) {
	    return 1;
	}
    }
    if ($Apache::lonhomework::type eq 'survey') { return 1; }
    if ($Apache::lonhomework::type eq 'surveycred') { return 1; }
    if ($Apache::lonhomework::type eq 'anonsurvey') { return 1; }
    if ($Apache::lonhomework::type eq 'anonsurveycred') { return 1; }

    return 0;
}

=pod

=item &getresponse();

Retreives the current submitted response, helps out in the case of
scantron mode.

Returns either the exact text of the submission, or a bubbled response
converted to something usable.

Optional Arguments:
  $offset - (defaults to 1) if a problem has more than one bubble
            response, pass in the number of the bubble wanted, (the
            first bubble associated with a problem has an offset of 1,
            the second bubble is 2

  $resulttype - undef    -> a number between 0 and 25
                'A is 1' -> a number between 1 and 26
                'letter' -> a letter between 'A' and 'Z'
  $lines  - undef problem only needs a single line of bubbles.
            nonzero  Problem wants the first nonempty response in 
                      $lines lines of bubbles.
  $bubbles_per_line - Must be provided if lines is defined.. number of
                      bubbles on a line.

=cut

sub getresponse {
    my ($offset,$resulttype, $lines, $bubbles_per_line)=@_;
    my $formparm='form.HWVAL_'.$Apache::inputtags::response['-1'];
    my $response;
    if (!defined($offset)) {
	$offset=1;
    } else {
	$formparm.=":$offset";
    }
    if (!defined($lines)) {
	$lines = 1;
    }
    my %let_to_num=('A'=>0,'B'=>1,'C'=>2,'D'=>3,'E'=>4,'F'=>5,'G'=>6,'H'=>7,
		    'I'=>8,'J'=>9,'K'=>10,'L'=>11,'M'=>12,'N'=>13,'O'=>14,
		    'P'=>15,'Q'=>16,'R'=>17,'S'=>18,'T'=>19,'U'=>20,'V'=>21,
		    'W'=>22,'X'=>23,'Y'=>24,'Z'=>25);
    if ($env{'form.submitted'} eq 'scantron') {
	my $part  = $Apache::inputtags::part;
	my $id    = $Apache::inputtags::response[-1];
	
	my $line;
	my $startline = $env{'form.scantron_questnum_start.'.$part.'.'.$id};
        if (!$startline) {
            $startline = $Apache::lonxml::counter;
        }
	for ($line = 0; $line < $lines; $line++) {
            my $theline = $startline+$offset-1+$line;
	    $response = $env{"scantron.$theline.answer"};
	    if ((defined($response)) && ($response ne "") && ($response ne " ")) {
		last;
	    }
 
	}

	# save bubbled letter for later
	$Apache::lonhomework::results{"resource.$part.$id.scantron"}.=
	    $response;
	if ($resulttype ne 'letter') {
            $response = $let_to_num{$response};
            if ($resulttype eq 'A is 1') {
                if ($response ne "") {
                    $response = $response+1;
                }
	    }
	    if ($response ne "") {
		$response += $line * $bubbles_per_line;
	    }
	} else {
	    if ($response ne "") {
                my $raw = $response;
		$response = chr(ord($response) + $line * $bubbles_per_line);
	    }
	}

    } else {
	$response = $env{$formparm};
    }
    # 
    #  If we have a nonempty answer, correct the numeric value
    #  of the answer for the line on which it was found.
    #

    return $response;
}

=pod

=item &repetition();

In scalar context:

returns: the number of lines that are required to encode the weight.
(Default is for 10 bubbles per bubblesheet item; other (integer) 
values can be specified by using a custom Bubblesheet format file 
with an eighteenth entry (BubblesPerRow) set to the integer 
appropriate for the bubblesheets which will be used to assign weights.

In array context:
 
returns: number of lines required to encode weight, and bubbles/line.

=cut

sub repetition {
    my $id = $Apache::inputtags::part;
    my $weight = &Apache::lonnet::EXT("resource.$id.weight");
    if (!defined($weight) || ($weight eq '')) { $weight=1; }
    my $bubbles_per_row;
    if (($env{'form.bubbles_per_row'} =~ /^\d+$/) && 
        ($env{'form.bubbles_per_row'} > 0)) {
        $bubbles_per_row = $env{'form.bubbles_per_row'};
    } else {
        $bubbles_per_row = 10;
    }
    my $denominator = $bubbles_per_row;
    if (($env{'form.scantron_lastbubblepoints'} == 0) && 
        ($bubbles_per_row > 1)) {
        $denominator = $bubbles_per_row - 1;
    } 
    my $repetition = int($weight/$denominator);
    if ($weight % $denominator != 0) { $repetition++; } 
    if (wantarray) {
        return ($repetition,$bubbles_per_row);
    }
    return $repetition;

}

=pod

=item &scored_response();

Sets the results hash elements

   resource.$part_id.$response_id.awarded - to the floating point
     number between 0 and 1 that was awarded on the bubbled input

   resource.$part_id.$response_id.awarddetail - to 'ASSIGNED_SCORE'

Returns

   the number of bubble sheet lines that were used (and likely need to
     be passed to &Apache::lonxml::increment_counter()

Arguments

   $part_id - id of the part to grade
   $response_id - id of the response to grade
  

=cut

sub scored_response {
    my ($part,$id)=@_;
    my $repetition=&repetition();
    my $bubbles_per_row;
    if (($env{'form.bubbles_per_row'} =~ /^\d+$/) &&
        ($env{'form.bubbles_per_row'} > 0)) {
        $bubbles_per_row = $env{'form.bubbles_per_row'};
    } else {
        $bubbles_per_row = 10;
    }
    my $score=0;
    for (my $i=0;$i<$repetition;$i++) {
	# A is 1, B is 2, etc.
	my $increase=&Apache::response::getresponse($i+1);
        unless (($increase == $bubbles_per_row-1) &&
                ($env{'form.scantron_lastbubblepoints'} == 0)) {
            # (get response return 0-9 and then we add 1)
            if ($increase ne '') {
                $score+=$increase+1;
            }
        }
    }
    my $weight = &Apache::lonnet::EXT("resource.$part.weight");
    if (!defined($weight) || $weight eq '' || $weight eq 0) { $weight = 1; }
    my $pcr=$score/$weight;
    $Apache::lonhomework::results{"resource.$part.$id.awarded"}=$pcr;
    $Apache::lonhomework::results{"resource.$part.$id.awarddetail"}=
	'ASSIGNED_SCORE';
    return $repetition;
}

sub whichorder {
    my ($max,$randomize,$showall,$hash,$rndseed)=@_;
    #&Apache::lonxml::debug("man $max randomize $randomize");
    my @names;
    if (ref($hash->{'names'}) eq 'ARRAY') {
        @names = @{$hash->{'names'}};
    }
    return if (!@names);
    my @whichopt =();
    my (%top,@toplist,%bottom,@bottomlist);
    if (!($showall || ($randomize eq 'no'))) {
	my $current=0;
	foreach my $name (@names) {
	    $current++;
	    if ($$hash{"$name.location"} eq 'top') {
		$top{$name}=$current;
	    } elsif ($$hash{"$name.location"} eq 'bottom') {
		$bottom{$name}=$current;
	    }
	}
    }
    my $topcount=0;
    my $bottomcount=0;
    while (((scalar(@whichopt)+$topcount+$bottomcount) < $max || $showall)
	   && ($#names > -1)) {
	#&Apache::lonxml::debug("Have $#whichopt max is $max");
	my $aopt;
	if ($showall || ($randomize eq 'no')) {
	    $aopt=0;
	} else {
	    $aopt=int(&Math::Random::random_uniform() * ($#names+1));
	}
	#&Apache::lonxml::debug("From $#whichopt $max $#names elms, picking $aopt");
	$aopt=splice(@names,$aopt,1);
	#&Apache::lonxml::debug("Picked $aopt");
	if ($top{$aopt}) {
	    $toplist[$top{$aopt}]=$aopt;
	    $topcount++;
	} elsif ($bottom{$aopt}) {
	    $bottomlist[$bottom{$aopt}]=$aopt;
	    $bottomcount++;
	} else {
	    push (@whichopt,$aopt);
	}
    }
    for (my $i=0;$i<=$#toplist;$i++) {
	if ($toplist[$i]) { unshift(@whichopt,$toplist[$i]) }
    }
    for (my $i=0;$i<=$#bottomlist;$i++) {
	if ($bottomlist[$i]) { push(@whichopt,$bottomlist[$i]) }
    }
    return @whichopt;
}

sub show_answer {
    my $part   = $Apache::inputtags::part;
    my $award  = $Apache::lonhomework::history{"resource.$part.solved"};
    my $status = $Apache::inputtags::status[-1];
    my $canshow = 0;
    if ($award =~ /^correct/) {
        if (($Apache::lonhomework::history{"resource.$part.awarded"} >= 1) ||
            (&Apache::lonnet::EXT("resource.$part.retrypartial") !~/^1|on|yes$/)) {
            $canshow = 1;
        }   
    }
    return  (($canshow && &Apache::lonhomework::show_problem_status()) 
	     || $status eq "SHOW_ANSWER");
}

sub analyze_store_foilgroup {
    my ($shown,$attrs)=@_;
    my $part_id="$Apache::inputtags::part.$Apache::inputtags::response[-1]";
    foreach my $name (@{ $Apache::response::foilgroup{'names'} }) {
	if (defined($Apache::lonhomework::analyze{"$part_id.foil.value.$name"})) { next; }
	push (@{ $Apache::lonhomework::analyze{"$part_id.foils"} },$name);
	foreach my $attr (@$attrs) {
	    $Apache::lonhomework::analyze{"$part_id.foil.".$attr.".$name"} =
		$Apache::response::foilgroup{"$name.".$attr};
	}
    }
    push (@{ $Apache::lonhomework::analyze{"$part_id.shown"} }, @{ $shown });
}

sub check_if_computed {
    my ($token,$parstack,$safeeval,$name)=@_;
    my $value = &Apache::lonxml::get_param($name,$parstack,$safeeval);
    if (ref($token->[2]) eq 'HASH' && $value ne $token->[2]{$name}) {
	my $part_id="$Apache::inputtags::part.$Apache::inputtags::response[-1]";
	$Apache::lonhomework::analyze{"$part_id.answercomputed"} = 1;
    }
}

sub pick_foil_for_concept {
    my ($target,$attrs,$hinthash,$parstack,$safeeval)=@_;
    my @names;
    if (ref($Apache::response::conceptgroup{'names'}) eq 'ARRAY') {
        @names = @{ $Apache::response::conceptgroup{'names'} };
    }
    return if (!@names);
    my $pick=int(&Math::Random::random_uniform() * ($#names+1));
    my $name=$names[$pick];
    push @{ $Apache::response::foilgroup{'names'} }, $name;
    foreach my $attr (@$attrs) {
	$Apache::response::foilgroup{"$name.".$attr} =
	    $Apache::response::conceptgroup{"$name.".$attr};
    }
    my $concept = &Apache::lonxml::get_param('concept',$parstack,$safeeval);
    $Apache::response::foilgroup{"$name.concept"} = $concept;
    &Apache::lonxml::debug("Selecting $name in $concept");
    my $part_id="$Apache::inputtags::part.$Apache::inputtags::response[-1]";
    if ($target eq 'analyze') {
	push (@{ $Apache::lonhomework::analyze{"$part_id.concepts"} },
	      $concept);
	$Apache::lonhomework::analyze{"$part_id.concept.$concept"}=
	    $Apache::response::conceptgroup{'names'};
	foreach my $name (@{ $Apache::response::conceptgroup{'names'} }) {
	    push (@{ $Apache::lonhomework::analyze{"$part_id.foils"} },
		  $name);
	    foreach my $attr (@$attrs) {
		$Apache::lonhomework::analyze{"$part_id.foil.$attr.$name"}=
		    $Apache::response::conceptgroup{"$name.$attr"};
	    }
	}
    }
    push(@{ $hinthash->{"$part_id.concepts"} },$concept);
    $hinthash->{"$part_id.concept.$concept"}=
	$Apache::response::conceptgroup{'names'};

}

=pod

=item get_response_param()

Get a parameter associated with a problem.
Parameters:
	$id        - the id of the paramater, either a part id, 
              or a partid and responspe id joined by _
	$name      - Name of the parameter to fetch
	$default   - Default value for the paramter.

=cut

sub get_response_param {
    my ($id,$name,$default)=@_;
    my $parameter;
    if ($env{'request.state'} eq 'construct' &&
	defined($Apache::inputtags::params{$name})) {
	$parameter=$Apache::inputtags::params{$name};
    } else {
	$parameter=&Apache::lonnet::EXT("resource.$id.$name");
    }
    if (!defined($parameter) ||	$parameter eq '') {
	$parameter = $default;
    }
    return $parameter;
}

sub submitted {
    my ($who)=@_;
    
    # when scatron grading any submission is a submission
    if ($env{'form.submitted'} eq 'scantron') { return 1; }
    # if the caller only cared if this was a scantron submission
    if ($who eq 'scantron') { return 0; }
    # if the Submit Answer button for this particular part was pressed
    my $partid=$Apache::inputtags::part;
    if ($env{'form.submitted'} eq "part_$partid") {
	return 1;
    }
    if ($env{'form.submitted'} eq "yes"
	&& defined($env{'form.submit_'.$partid})) {
	return 1;
    }
    # Submit All button on a .page was pressed
    if ($env{'form.all_submit'}) { return 1; }
    # otherwise no submission occurred
    return 0;
}

sub add_to_gradingqueue {
    my ($symb,$courseid,$domain,$name) = &Apache::lonnet::whichuser();
    if (   $courseid eq ''
	|| $symb eq ''
	|| $env{'request.state'} eq 'construct'
	|| $Apache::lonhomework::type ne 'problem') {
	return;
    }

    my %queue_info = ( 'type' => 'problem',
		       'time' => time);

    if (exists($Apache::lonhomework::history{"resource.0.checkedin.slot"})) {
	$queue_info{'slot'}=
	     $Apache::lonhomework::history{"resource.0.checkedin.slot"};
    }

    my $result=&Apache::bridgetask::add_to_queue('gradingqueue',\%queue_info);
    if ($result ne 'ok') {
	&Apache::lonxml::error("add_to_queue said $result");
    }
}

=pod 

=item check_status()

basically undef and 0 (both false) mean that they still have work to do
and all true values mean that they can't do any more work

	a return of undef means it is unattempted
	a return of 0 means it is both attempted and still has tries and
                      is wrong or is only partially correct, and retries 
                      are allowed.
	a return of 1 means it is marked correct
	a return of 2 means they have exceeded maximum number of tries
	a return of 3 means it is after the answer date

=cut

sub check_status {
    my ($id)=@_;
    if (!defined($id)) { $id=$Apache::inputtags::part; }
    my $curtime=&Apache::lonnet::EXT('system.time');
    my $opendate=&Apache::lonnet::EXT("resource.$id.opendate");
    my $duedate=&Apache::lonhomework::due_date($id);
    my $answerdate=&Apache::lonnet::EXT("resource.$id.answerdate");
    if ( $opendate && $curtime > $opendate &&
         $duedate && $curtime > $duedate &&
         $answerdate && $curtime > $answerdate) {
        return 3;
    }
    my $status=&Apache::lonnet::EXT("user.resource.resource.$id.solved");
    if ($status =~ /^correct/) { 
        my $awarded=&Apache::lonnet::EXT("user.resource.resource.$id.awarded");
        my $retrypartial=&Apache::lonnet::EXT("resource.$id.retrypartial");
        unless (($retrypartial =~ /^1|on|yes$/) && ($awarded <1))  {
            return 1;
        }
    }
    if (!$status) { return undef; }
    my $maxtries=&Apache::lonnet::EXT("resource.$id.maxtries");
    if ($maxtries eq '') { $maxtries=2; }
    my $curtries=&Apache::lonnet::EXT("user.resource.resource.$id.tries");
    if ($curtries < $maxtries) { return 0; }
    return 2;
}

=pod

=item setup_prior_tries_hash()

  Foreach each past .submission $func is called with 3 arguments
     - the mode to set things up for (currently always 'grade')
     - the stored .submission string
     - The expansion of $data

  $data is an array ref containing elements that are either
    - scalars that are other elements of the history hash to pass to $func
    - ref to data to be passed untouched to $func

  $questiontype is the questiontype (currently only passed in if
      randomizebytry.

=cut

sub setup_prior_tries_hash {
    my ($func,$data,$questiontype) = @_;
    my $part = $Apache::inputtags::part;
    my $id   = $Apache::inputtags::response[-1];
    foreach my $i (1..$Apache::lonhomework::history{'version'}) {
        my $partprefix = "$i:resource.$part";
	my $sub_key   = "$partprefix.$id.submission";
	next if (!exists($Apache::lonhomework::history{$sub_key}));
        my $type_key = "$partprefix.type";
        my $type = $Apache::lonhomework::history{$type_key};
	my @other_data;
        if (ref($data) eq 'ARRAY') {
	    foreach my $datum (@{ $data }) {
	        if (ref($datum)) {
		    push(@other_data,$datum);
	        } else {
		    my $info_key = "$i:resource.$part.$id.$datum";
		    push(@other_data,$Apache::lonhomework::history{$info_key});
	        }
	    }
        }
        if ($questiontype eq 'randomizetry') { 
            my $order_key = "$partprefix.$id.foilorder";
            my @whichopts = &Apache::lonnet::str2array($Apache::lonhomework::history{$order_key});
            if (@whichopts > 0) {
                shift(@other_data);
                unshift(@other_data,\@whichopts);
            }
        }
	my $output =
	    &$func('grade',
		   $Apache::lonhomework::history{$sub_key},
		   \@other_data);
	if (defined($output)) {
	    $Apache::inputtags::submission_display{$sub_key} = $output;
	}
    }
}

1;
__END__
 
=pod

=cut

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