--- a/libinterp/parse-tree/oct-parse.in.yy
+++ b/libinterp/parse-tree/oct-parse.in.yy
@@ -1,6 +1,6 @@
 /*
 
-Copyright (C) 1993-2012 John W. Eaton
+Copyright (C) 1993-2013 John W. Eaton
 Copyright (C) 2009 David Grundberg
 Copyright (C) 2009-2010 VZLU Prague
 
@@ -107,16 +107,6 @@
 
 static void yyerror (octave_base_parser& parser, const char *s);
 
-// Finish building a statement.
-template <class T>
-static tree_statement *
-make_statement (T *arg)
-{
-  octave_comment_list *comment = octave_comment_buffer::get_comment ();
-
-  return new tree_statement (arg, comment);
-}
-
 #define ABORT_PARSE \
   do \
     { \
@@ -136,6 +126,11 @@
 
 // Bison declarations.
 
+// The grammar currently has 14 shift/reduce conflicts.  Ensure that
+// we notice if that number changes.
+
+%expect 14
+
 // Don't add spaces around the = here; it causes some versions of
 // bison to fail to properly recognize the directive.
 
@@ -418,11 +413,11 @@
                 ;
 
 statement       : expression
-                  { $$ = make_statement ($1); }
+                  { $$ = parser.make_statement ($1); }
                 | command
-                  { $$ = make_statement ($1); }
+                  { $$ = parser.make_statement ($1); }
                 | word_list_cmd
-                  { $$ = make_statement ($1); }
+                  { $$ = parser.make_statement ($1); }
                 ;
 
 // =================
@@ -1687,7 +1682,7 @@
                 ;
 
 stash_comment   : // empty
-                  { $$ = octave_comment_buffer::get_comment (); }
+                  { $$ = lexer.get_comment (); }
                 ;
 
 parse_error     : LEXICAL_ERROR
@@ -1762,11 +1757,6 @@
   delete &lexer;
 }
 
-void octave_base_parser::init (void)
-{
-  LEXER = &lexer;
-}
-
 void
 octave_base_parser::reset (void)
 {
@@ -2447,7 +2437,7 @@
 
   if (end_token_ok (end_tok, token::unwind_protect_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = unwind_tok->line ();
       int c = unwind_tok->column ();
@@ -2479,7 +2469,7 @@
 
   if (end_token_ok (end_tok, token::try_catch_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = try_tok->line ();
       int c = try_tok->column ();
@@ -2499,6 +2489,9 @@
                   id = dynamic_cast<tree_identifier *> (expr);
 
                   cleanup_stmts->pop_front ();
+
+                  stmt->set_expression (0);
+                  delete stmt;
                 }
             }
         }
@@ -2530,7 +2523,7 @@
 
   if (end_token_ok (end_tok, token::while_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       lexer.looping--;
 
@@ -2558,7 +2551,7 @@
 {
   maybe_warn_assign_as_truth_value (expr);
 
-  octave_comment_list *tc = octave_comment_buffer::get_comment ();
+  octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
   lexer.looping--;
 
@@ -2585,7 +2578,7 @@
 
   if (end_token_ok (end_tok, parfor ? token::parfor_end : token::for_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       lexer.looping--;
 
@@ -2679,7 +2672,7 @@
 
   if (end_token_ok (end_tok, token::if_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = if_tok->line ();
       int c = if_tok->column ();
@@ -2732,7 +2725,7 @@
 
   if (end_token_ok (end_tok, token::switch_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = switch_tok->line ();
       int c = switch_tok->column ();
@@ -2916,7 +2909,7 @@
 
   if (fcn)
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       fcn->stash_trailing_comment (tc);
       fcn->stash_fcn_end_location (end_fcn_stmt->line (),
@@ -3187,7 +3180,7 @@
     bison_error ("invalid classdef definition, the class name must match the file name");
   else if (end_token_ok (end_tok, token::classdef_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = tok_val->line ();
       int c = tok_val->column ();
@@ -3218,7 +3211,7 @@
 
   if (end_token_ok (end_tok, token::properties_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = tok_val->line ();
       int c = tok_val->column ();
@@ -3245,7 +3238,7 @@
 
   if (end_token_ok (end_tok, token::methods_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = tok_val->line ();
       int c = tok_val->column ();
@@ -3272,7 +3265,7 @@
 
   if (end_token_ok (end_tok, token::events_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = tok_val->line ();
       int c = tok_val->column ();
@@ -3299,7 +3292,7 @@
 
   if (end_token_ok (end_tok, token::enumeration_end))
     {
-      octave_comment_list *tc = octave_comment_buffer::get_comment ();
+      octave_comment_list *tc = lexer.comment_buf.get_comment ();
 
       int l = tok_val->line ();
       int c = tok_val->column ();
@@ -3649,6 +3642,16 @@
   return list;
 }
 
+// Finish building a statement.
+template <class T>
+tree_statement *
+octave_base_parser::make_statement (T *arg)
+{
+  octave_comment_list *comment = lexer.get_comment ();
+
+  return new tree_statement (arg, comment);
+}
+
 tree_statement_list *
 octave_base_parser::make_statement_list (tree_statement *stmt)
 {
@@ -3729,8 +3732,6 @@
 octave_push_parser::init (void)
 {
   parser_state = yypstate_new ();
-
-  octave_base_parser::init ();
 }
 
 // Parse input from INPUT.  Pass TRUE for EOF if the end of INPUT should
@@ -3770,15 +3771,6 @@
 static void
 safe_fclose (FILE *f)
 {
-  // FIXME -- comments at the end of an input file are
-  // discarded (otherwise, they would be appended to the next
-  // statement, possibly from the command line or another file, which
-  // can be quite confusing).
-
-  octave_comment_list *tc = octave_comment_buffer::get_comment ();
-
-  delete tc;
-
   if (f)
     fclose (static_cast<FILE *> (f));
 }
@@ -4574,11 +4566,6 @@
 {
   octave_value_list retval;
 
-  unwind_protect frame;
-
-  // octave_base_parser constructor sets this for us.
-  frame.protect_var (LEXER);
-
   octave_parser parser (eval_str);
 
   do
@@ -4587,9 +4574,6 @@
 
       parse_status = parser.run ();
 
-      // Unmark forced variables.
-      frame.run (1);
-
       if (parse_status == 0)
         {
           if (parser.stmt_list)