--- loncom/interface/lonprintout.pm	2006/10/16 10:32:46	1.486
+++ loncom/interface/lonprintout.pm	2006/10/24 10:37:58	1.490
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # Printout
 #
-# $Id: lonprintout.pm,v 1.486 2006/10/16 10:32:46 foxr Exp $
+# $Id: lonprintout.pm,v 1.490 2006/10/24 10:37:58 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -61,26 +61,38 @@ 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:
-
+    my $result = "";
+    while ($format_string =~ /(%)(\d*)\Q$item\E/g ) {
+	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/;
+	    
+	    #  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 $item_pos = pos($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;
 }
 
 
@@ -135,6 +147,12 @@ 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!!!
+
+
     }
     
 
@@ -158,7 +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;