--- loncom/homework/caparesponse/caparesponse.pm	2012/12/14 11:17:09	1.253
+++ loncom/homework/caparesponse/caparesponse.pm	2018/09/13 17:00:05	1.259
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # caparesponse definition
 #
-#  caparesponse.pm,v 1.249.8.2 2012/02/04 20:40:15 foxr 
+# $Id: caparesponse.pm,v 1.259 2018/09/13 17:00:05 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -446,7 +446,6 @@ sub check_submission {
     }
 
     my (@final_awards,@final_msgs,@names);
-    # $Apache::lonxml::debug = 1;	# DEBUG
     foreach my $name (keys(%answer)) {
 	&Apache::lonxml::debug(" doing $name with ".join(':',@{ $answer{$name}{'answers'} }));
 	
@@ -465,7 +464,6 @@ sub check_submission {
 	push(@final_msgs,$msg);
 	push(@names,$name);
     }
-    # $Apache::lonxml::debug = 0;	# DEBUG
     my ($ad, $msg, $name) = &Apache::inputtags::finalizeawards(\@final_awards,
 							       \@final_msgs,
 							       \@names,1);
@@ -644,12 +642,7 @@ sub end_numericalresponse {
 		}
 	    }
 	}
-        if (($target eq 'web') && ($tag eq 'formularesponse')
-            && ($Apache::lonhomework::type ne 'exam') && ($Apache::inputtags::status['-1'] eq 'CAN_ANSWER')
-	    && (&Apache::lonnet::EXT('resource.'.$partid.'_'.$id.'.turnoffeditor') ne 'yes')) {
-            $result.=&Apache::response::edit_mathresponse_button($id,"HWVAL_$id");
-        }
-            
+
 	&Apache::response::setup_prior_tries_hash(\&format_prior_response_numerical);
     } elsif ($target eq 'edit') {
 	$result.='</td></tr>'.&Apache::edit::end_table;
@@ -671,7 +664,14 @@ sub end_numericalresponse {
 	my (@formats)=&Apache::lonxml::get_param_var('format',$parstack,$safeeval);
 
 	my $unit=&Apache::lonxml::get_param_var('unit',$parstack,$safeeval);
-	
+	my ($needsdollar,$needscomma);
+	if ($unit =~ /\$/) {
+	    $needsdollar = 1;
+	}
+	if ($unit =~ /\,/) {
+	    $needscomma = 1;
+	}
+
 	if ($target eq 'answer') {
 	    $result.=&Apache::response::answer_header($tag,undef,
 						      scalar(keys(%answer)));
@@ -767,7 +767,7 @@ sub end_numericalresponse {
 			if ($unit=~/\,/) { $fmt="\,".$fmt; $unit=~s/\,//g; }
 			$element = &format_number($element,$fmt,$target,
 						  $safeeval);
-			if ($fmt=~/\$/ && $unit!~/\$/) { $element=~s/\$//; }
+			if ($fmt=~/\$/ && !$needsdollar) { $element=~s/\$//; }
 		    }
 		}
 		push(@fmt_ans,join(',',@$ans));
@@ -780,24 +780,11 @@ sub end_numericalresponse {
 		! ($Apache::lonhomework::type eq 'exam' ||
 		   lc($hideunit) eq "yes") )  {
 		my $cleanunit=$unit;
-		$cleanunit=~s/\$\,//g;
+		$cleanunit=~s/[\$,]//g;
 		foreach my $ans (@fmt_ans) {
 		    $ans.=" $cleanunit";
 		}
 	    }
-	    #
-	    # The computer's response must be cast in a form that 
-	    # ensures it has sufficient significant figures.
-	    # the only way to do this is to sprintf it into scientific notation
-	    # due to the ambiguity of trailing zeros.
-	    # See Bug 6577
-	    #
-	    my ($sigMax, $sigmin) = &get_sigrange($Apache::inputtags::params{'sig'});
-	    my $sigfigs = $sigMax-1;
-
-	    for (my $i = 0; $i < scalar @$response; $i++) {
-		$response->[$i] = sprintf('%.' . $sigfigs . 'e', $response->[$i]);
-	    }
 	    my ($ad,$msg)=&check_submission($response,$partid,$id,$tag,
 					    $parstack,$safeeval);
 	    if ($ad ne 'EXACT_ANS' && $ad ne 'APPROX_ANS') {
@@ -810,7 +797,16 @@ sub end_numericalresponse {
 						    $tag,$parstack,
 						    $safeeval,1);
 		    $error=&mt("Computer's answer is incorrect ([_1]).",'"'.join(', ',@$response).'"').' ';
-		    if ($sigline ne '') {
+                    if (($ad eq 'NO_UNIT') && $needsdollar) {
+                        $error.=&mt('The unit attribute includes [_1] but the answer format does not.','$').' '.
+                                &mt('Either remove the [_1] from the unit or prepend [_1] to the answer format.','$');    
+                    } elsif (($ad eq 'COMMA_FAIL') && $needscomma) {
+                        $error.=&mt('The unit attribute includes [_1] but the answer format does not.',',').' '.
+                                &mt('Either remove the [_1] from the unit or prepend [_1] to the answer format.',',');
+                    } elsif ($ad eq 'UNIT_INVALID_STUDENT') {
+                        $error.=&mt('Unable to interpret units. Computer reads units as "[_1]".',$msg).' '.
+                                &mt('The unit attribute in the numericalresponse item needs to be a supported physical unit.');
+		    } elsif ($sigline ne '') {
 			$error.=&mt('It is likely that the tolerance range [_1] or significant figures [_2] need to be adjusted.',$tolline,$sigline);
 		    } else {
 			$error.=&mt('It is likely that the tolerance range [_1] needs to be adjusted.',$tolline);
@@ -911,7 +907,7 @@ sub get_table_sizes {
     my $cell_width=0;
     foreach my $member (@$rbubble_values) {
 	my $cell_width_real=0;
-	if ($member=~/(\+|-)?(\d*)\.?(\d*)\s*\$?\\times\s*10\^{(\+|-)?(\d+)}\$?/) {
+	if ($member=~/(\+|-)?(\d*)\.?(\d*)\s*\$?\\times\s*10\^\{(\+|-)?(\d+)}\$?/) {
 	    $cell_width_real=(length($2)+length($3)+length($5)+7)*$scale;
 	} elsif ($member=~/(\d*)\.?(\d*)(E|e)(\+|-)?(\d*)/) {
 	    $cell_width_real=(length($1)+length($2)+length($5)+9)*$scale;