--- loncom/interface/lonprintout.pm	2006/10/23 10:40:09	1.489
+++ loncom/interface/lonprintout.pm	2006/10/24 10:37:58	1.490
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # Printout
 #
-# $Id: lonprintout.pm,v 1.489 2006/10/23 10:40:09 foxr Exp $
+# $Id: lonprintout.pm,v 1.490 2006/10/24 10:37:58 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -61,19 +61,38 @@ my $resources_printed;
 #
 sub printf_style_subst {
     my ($item, $format_string, $repl) = @_;
-
-    while ($format_string =~m/%\d*\Q$item\E/) {
+    my $result = "";
+    while ($format_string =~ /(%)(\d*)\Q$item\E/g ) {
 	my $fmt = $1;
 	my $size = $2;
 	my $subst = $repl;
 	if ($size ne "") {
 	    $subst = substr($subst, 0, $size);
+	    
+	    #  Here's a nice edge case.. supose the end of the
+	    #  substring is a \.  In that case may have  just
+	    #  chopped off a TeX escape... in that case, we append
+	    #   " " for the trailing character, and let the field 
+	    #  spill over a bit (sigh).
+	    #  We don't just chop off the last character in order to deal
+	    #  with one last pathology, and that would be if substr had
+	    #  trimmed us to e.g. \\\  
+
+
+	    if ($subst =~ /\\$/) {
+		$subst .= " ";
+	    }
 	}
-	my $newpos =  pos($format_string) + length($subst) - length($fmt);
-	$format_string =~ s/\Q$fmt\E/$subst/;
-	pos($format_string)=$newpos;
+	my $item_pos = pos($format_string);
+	$result .= substr($format_string, 0, $item_pos - length($size) -2) . $subst;
+        $format_string = substr($format_string, pos($format_string));
     }
-    return $format_string;
+
+    # Put the residual format string into the result:
+
+    $result .= $format_string;
+
+    return $result;
 }
 
 
@@ -133,7 +152,7 @@ sub format_page_header {
 	# to \% else LaTeX will think they are comments and terminate
 	# the line.. which is bad!!!
 
-	$format =~ s/%/\\%/g;
+
     }
     
 
@@ -157,7 +176,7 @@ sub num_to_letters {
 sub letters_to_num {
     my ($letters) = @_;
     my @letters = split('', uc($letters));
-    my %substitution;
+   my %substitution;
     my $digit = 0;
     foreach my $letter ('A'..'J') {
 	$substitution{$letter} = $digit;