Update the Rserve interface.

conf/pg_config.dist.yml

@@ -139,6 +139,12 @@ specialPGEnvironmentVars:
   # Size in pixels of dynamically-generated images, i.e. graphs.
   onTheFlyImageSize: 400
 
+  # To enable Rserve (the R statistical server), uncomment the following two
+  # lines. The R server needs to be installed and running in order for this to
+  # work. See http://webwork.maa.org/wiki/R_in_WeBWorK for more info.
+  #Rserve:
+  #  host: localhost
+
   # Locations of CAPA resources. (Only necessary if you need to use converted CAPA problems.)
   CAPA_Tools: $Contrib_dir/CAPA/macros/CAPA_Tools/
   CAPA_MCTools: $Contrib_dir/Contrib/CAPA/macros/CAPA_MCTools/

lib/Rserve.pm

@@ -11,53 +11,34 @@ my $rserve_loaded = eval {
 sub access {
 	die 'Statistics::R::IO::Rserve could not be loaded. Have you installed the module?'
 		unless $rserve_loaded;
-
-	Statistics::R::IO::Rserve->new(@_);
+	return Statistics::R::IO::Rserve->new(@_);
 }
 
-## Evaluates an R expression guarding it inside an R `try` function
-##
-## Returns the result as a REXP if no exceptions were raised, or
-## `die`s with the text of the exception message.
+# Evaluates an R expression guarding it inside an R `try` function
+#
+# Returns the result as a REXP if no exceptions were raised, or
+# `die`s with the text of the exception message.
 sub try_eval {
 	my ($rserve, $query) = @_;
 
-	my $result = $rserve->eval("try({ $query }, silent=TRUE)");
-	die $result->to_pl->[0] if _inherits($result, 'try-error');
-	# die $result->to_pl->[0] if $result->inherits('try-error');
+	my $result = $rserve->eval("try({ $query }, silent = TRUE)");
+	die $result->to_pl->[0] if $result->inherits('try-error');
 
-	$result;
+	return $result;
 }
 
-## Returns a REXP's Perl representation, dereferencing it if it's an
-## array reference
-##
-## `REXP::to_pl` returns a string scalar for Symbol, undef for Null,
-## and an array reference to contents for all vector types. This
-## function is a utility wrapper to make it easy to assign a Vector's
-## representation to an array variable, while still working sensibly
-## for non-arrays.
+# Returns a REXP's Perl representation, dereferencing it if it's an
+# array reference
+#
+# `REXP::to_pl` returns a string scalar for Symbol, undef for Null,
+# and an array reference to contents for all vector types. This
+# function is a utility wrapper to make it easy to assign a Vector's
+# representation to an array variable, while still working sensibly
+# for non-arrays.
 sub unref_rexp {
-	my $rexp = shift;
-
+	my $rexp  = shift;
 	my $value = $rexp->to_pl;
-	if (ref($value) eq ref([])) {
-		@{$value};
-	} else {
-		$value;
-	}
-}
-
-## Reimplements method C<inherits> of class L<Statistics::R::REXP>
-## until I figure out why calling it directly doesn't work in the safe
-## compartment
-sub _inherits {
-	my ($rexp, $class) = @_;
-
-	my $attributes = $rexp->attributes;
-	return unless $attributes && $attributes->{'class'};
-
-	grep {/^$class$/} @{ $attributes->{'class'}->to_pl };
+	return ref($value) eq 'ARRAY' ? @$value : $value;
 }
 
 1;

macros/core/PGbasicmacros.pl

@@ -2231,11 +2231,6 @@ =head2 Formatting macros
                     # The function should be called either with value specified (immediate reference) or
                     # with url specified in which case the revealed text is taken from the URL $url.
                     # The $display_text is always visible and is clicked to see the contents of the knowl.
-    htmlLink($url, $text)
-                    # Places a reference to the URL with the specified text in the problem.
-                    # A common usage is \{ htmlLink(alias('prob1_help.html') \}, 'for help')
-                    # where alias finds the full address of the prob1_help.html file in the same directory
-                    # as the problem file
     iframe($url, height=>'', width=>'', id=>'', name=>'' )
                     # insert the web page referenced by $url in a space defined by height and width
                     # if the webpage contains a form then this must be inserted between
@@ -2362,18 +2357,31 @@ sub OL {
 	);
 }
 
+=head2 htmlLink
+
+Usage: C<htmlLink($url, $text, @attributes)>
+
+Places an HTML link to C<$url> with the specified C<$text> in the problem. The
+C<@attributes> are optional.  They should be provided as attribute/value pairs,
+but a single text string argument can be given (although calling C<htmlLink> in
+that way is deprecated and should not be done in new problems).  For example,
+
+    BEGIN_PGML
+    Download the [@ htmlLink($url, 'dataset', download => 'dataset.csv') @]*
+    for this problem.
+
+=cut
+
 sub htmlLink {
-	my $url           = shift;
-	my $text          = shift;
-	my $options       = shift;
-	my $sanitized_url = $url;
-	$sanitized_url =~ s/&/&amp;/g;
-	$options = ""                                             unless defined($options);
-	return "$BBOLD [ the link to '$text'  is broken ] $EBOLD" unless defined($url) and $url;
+	my ($url, $text, @options) = @_;
+	return "$BBOLD [ the link to '$text'  is broken ] $EBOLD" unless $url;
+	my $attributes = @options == 1 ? $options[0] : {@options};
 	MODES(
 		TeX  => "{\\bf \\underline{$text}}",
-		HTML => "<A HREF=\"$url\" $options>$text</A>",
-		PTX  => "<url href=\"$sanitized_url\">$text</url>",
+		HTML => ref($attributes) eq 'HASH'
+		? tag('a', href => $url, %$attributes, $text)
+		: qq{<a href="$url" $attributes>$text</a>},
+		PTX => '<url href="' . ($url =~ s/&/&amp;/g) . qq{">$text</url>},
 	);
 }