--- Stream.pm.orig	Tue May  3 16:41:37 2005
+++ Stream.pm	Mon Aug 29 20:00:14 2005
@@ -11,13 +11,16 @@
 
 ## Chapter 6 section 2
 
+use strict;
+use warnings;
+
 package Stream;
-use base Exporter;
-@EXPORT_OK = qw(node head tail drop upto upfrom show promise
+use base 'Exporter';
+@Stream::EXPORT_OK = qw(node head tail drop upto upfrom show promise
                 filter transform merge list_to_stream cutsort
                 iterate_function cut_loops);
 
-%EXPORT_TAGS = ('all' => \@EXPORT_OK);
+%Stream::EXPORT_TAGS = ('all' => \@Stream::EXPORT_OK);
 
 sub node {
   my ($h, $t) = @_;
@@ -29,13 +32,13 @@
   $s->[0];
 }
 
-sub tail {
-  my ($s) = @_;
-  if (is_promise($s->[1])) {
-    return $s->[1]->();
-  }
-  $s->[1];
-}
+# sub tail {
+#   my ($s) = @_;
+#   if (is_promise($s->[1])) {
+#     return $s->[1]->();
+#   }
+#   $s->[1];
+# }
 
 sub is_promise {
   UNIVERSAL::isa($_[0], 'CODE');