--- loncom/interface/lonprintout.pm	2006/10/16 10:32:46	1.486
+++ loncom/interface/lonprintout.pm	2006/10/23 10:40:09	1.489
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # Printout
 #
-# $Id: lonprintout.pm,v 1.486 2006/10/16 10:32:46 foxr Exp $
+# $Id: lonprintout.pm,v 1.489 2006/10/23 10:40:09 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -62,24 +62,17 @@ my $resources_printed;
 sub printf_style_subst {
     my ($item, $format_string, $repl) = @_;
 
-    while ($format_string =~ /%\d*$item/) {
-	my $start = $-[0];
-	my $end   = $+[0];
-	my $len   = $end - $start;
-
-	# see if we need to truncate:
-
+    while ($format_string =~m/%\d*\Q$item\E/) {
+	my $fmt = $1;
+	my $size = $2;
 	my $subst = $repl;
-	my $fmt   = substr($format_string, $start, $len);
-	my $size  = $fmt;
-	$size     =~ s/%(\d*)$item/$1/;
 	if ($size ne "") {
 	    $subst = substr($subst, 0, $size);
 	}
-	$format_string =~ s/%(\d*)$item/$subst/;
-
+	my $newpos =  pos($format_string) + length($subst) - length($fmt);
+	$format_string =~ s/\Q$fmt\E/$subst/;
+	pos($format_string)=$newpos;
     }
-
     return $format_string;
 }
 
@@ -135,6 +128,12 @@ sub format_page_header {
 	$format =  &printf_style_subst("a", $format, $assignment);
 	$format =  &printf_style_subst("c", $format, $course);
 	$format =  &printf_style_subst("n", $format, $student);
+
+	# If the user put %'s in the format string, they  must be escaped
+	# to \% else LaTeX will think they are comments and terminate
+	# the line.. which is bad!!!
+
+	$format =~ s/%/\\%/g;
     }