new file mode 100644
--- /dev/null
+++ b/src/symtab.h
@@ -0,0 +1,234 @@
+// Symbol table classes.                              -*- C++ -*-
+/*
+
+Copyright (C) 1992, 1993 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#if !defined (_symtab_h)
+#define _symtab_h 1
+
+#ifdef __GNUG__
+#pragma interface
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <iostream.h>
+#include <assert.h>
+
+#ifndef SV_FUNCTION_TYPEDEFS
+#define SV_FUNCTION_TYPEDEFS 1
+
+typedef int (*sv_Function)(void);
+
+#endif
+
+#define HASH_TABLE_SIZE 1024             /* Must be multiple of 2 */
+#define HASH_MASK (HASH_TABLE_SIZE - 1)
+
+class tree;
+class tree_builtin;
+class tree_constant;
+class tree_function;
+
+class symbol_def;
+class symbol_record;
+class symbol_table;
+
+/*
+ * Variables or functions.
+ */
+class symbol_def
+{
+  friend class symbol_record;
+
+public:
+
+  enum symbol_type
+    {
+      unknown_type,
+      variable,
+      builtin_function,
+      user_function,
+    };
+
+  enum symbol_lifespan
+    {
+      temporary,
+      eternal,
+    };
+
+  enum symbol_class
+    {
+      read_write,
+      read_only,
+    };
+
+  symbol_def (void);
+  symbol_def (tree_constant *t);
+  symbol_def (tree_builtin *t);
+  symbol_def (tree_function *t);
+
+  ~symbol_def (void);
+
+  void define (tree_constant *t);
+  void define (tree_builtin *t);
+  void define (tree_function *t);
+
+  tree *def (void);
+  char *help (void);
+  void document (char *h);
+
+  int save (ostream& os, int mark_as_global);
+
+private:
+
+  char *help_string;
+  symbol_lifespan lifespan;
+  symbol_class sym_class;
+  symbol_type type;
+  tree *definition;
+  int count;
+  int preserve;
+
+  symbol_def (const symbol_def& sd);
+  symbol_def& operator = (const symbol_def& sd);
+};
+
+/*
+ * Individual records in a symbol table.
+ */
+class
+symbol_record
+{
+ friend class symbol_table;
+
+public:
+  symbol_record (void);
+  symbol_record (char *n);
+  symbol_record (char *n, symbol_record *nxt);
+
+ ~symbol_record (void);
+
+  char *name (void);
+  char *help (void); 
+  tree *def (void);
+
+  int is_function (void);
+  int is_variable (void);
+
+  int is_defined (void);
+
+  void set_sv_function (sv_Function f);
+
+  int var_read_only (void);
+  int read_only (void);
+
+  int define (tree_constant *t);
+  int define (tree_builtin *t);
+  int define (tree_function *t);
+  int define_as_fcn (tree_constant *t);
+
+  void document (char *h);
+
+  void protect (void);
+  void unprotect (void);
+  void make_eternal (void);
+
+  int save (ostream& os, int mark_as_global = 0);
+
+  void clear_visible (void);
+  void clear_all (void);
+  void undefine (void);
+
+  void mark_as_formal_parameter (void);
+  int is_formal_parameter (void);
+
+  void alias (symbol_record *s, int force = 0);
+
+  symbol_record *next (void);
+
+private:
+
+  char *nm;
+  int formal_param;
+  symbol_def *var;
+  symbol_def *fcn;
+  sv_Function sv_fcn;
+  symbol_record *next_elem;
+
+  symbol_record (const symbol_record& s);
+  symbol_record& operator = (const symbol_record& s);
+};
+
+/*
+ * A symbol table.
+ */
+class
+symbol_table
+{
+public:
+
+  symbol_table (void);
+
+  symbol_record *lookup (char *nm, int insert = 0, int warn = 0);
+
+  void clear (void);
+  int clear (char *nm);
+  void undefine (void);
+
+  void bind_globals (void);
+
+  int save (ostream& os, int mark_as_global = 0);
+  int save (ostream& os, char *name, int mark_as_global = 0);
+
+  int size (void);
+
+  char **list (void);
+  char **var_list (void);
+  char **fcn_list (void);
+
+  char **list (int& count);
+  char **var_list (int& count);
+  char **fcn_list (int& count);
+
+  char **sorted_list (void);
+  char **sorted_var_list (void);
+  char **sorted_fcn_list (void);
+
+  char **sorted_list (int& count);
+  char **sorted_var_list (int& count);
+  char **sorted_fcn_list (int& count);
+
+private:
+
+  unsigned int hash (const char *s);
+
+  symbol_record table[HASH_TABLE_SIZE];
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/