--- loncom/xml/lonxml.pm	2006/01/13 10:33:25	1.395
+++ loncom/xml/lonxml.pm	2006/02/04 22:11:42	1.396
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # XML Parser Module 
 #
-# $Id: lonxml.pm,v 1.395 2006/01/13 10:33:25 albertel Exp $
+# $Id: lonxml.pm,v 1.396 2006/02/04 22:11:42 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -149,6 +149,19 @@ $Apache::lonxml::post_evaluate=1;
 #a header message to emit in the case of any generated warning or errors
 $Apache::lonxml::warnings_error_header='';
 
+#  Control whether or not LaTeX symbols should be substituted for their
+#  \ style equivalents...this may be turned off e.g. in an verbatim
+#  environment.
+
+$Apache::lonxml::substitute_LaTeX_symbols = 1; # Starts out on.
+
+sub enable_LaTeX_substitutions {
+    $Apache::lonxml::substitute_LaTeX_symbols = 1;
+}
+sub disable_LaTeX_substitutions {
+    $Apache::lonxml::substitute_LaTeX_symbols = 0;
+}
+
 sub xmlbegin {
     my ($style)=@_;
     my $output='';
@@ -382,6 +395,13 @@ sub xmlparse {
 
 sub latex_special_symbols {
     my ($string,$where)=@_;
+    #
+    #  If e.g. in verbatim mode, then don't substitute.
+    #  but return original string.
+    #
+    if (!($Apache::lonxml::substitute_LaTeX_symbols)) {
+	return $string;
+    }
     if ($where eq 'header') {
 	$string =~ s/(\\|_|\^)/ /g;
 	$string =~ s/(\$|%|\{|\})/\\$1/g;