/* classes: h_files */

#ifndef SYMBOLSH
#define SYMBOLSH
/*	Copyright (C) 1995,1996,1997,1998, 2000 Free Software Foundation, Inc.
 * 
 * This program 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.
 * 
 * This program 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 this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
   gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */


#include "libguile/__scm.h"


extern int scm_symhash_dim;

/* SCM_LENGTH(SYM) is the length of SYM's name in characters, and
   SCM_CHARS(SYM) is the address of the first character of SYM's name.

   Beyond that, there are two kinds of symbols: ssymbols and msymbols,
   distinguished by the 'S' bit in the type.

   Ssymbols are just uniquified strings.  They have a length, chars,
   and that's it.  They use the scm_tc7_ssymbol tag (S bit clear).

   Msymbols are symbols with extra slots.  These slots hold a property
   list and a function value (for Emacs Lisp compatibility), and a hash
   code.  They use the scm_tc7_msymbol tag.

   We'd like SCM_CHARS to work on msymbols just as it does on
   ssymbols, so we'll have it point to the symbol's name as usual, and
   store a pointer to the slots just before the name in memory.  Thus,
   you have to do some casting and pointer arithmetic to find the
   slots; see the SCM_SLOTS macro.

   In practice, the slots always live just before the pointer to them.
   So why not ditch the pointer, and use negative indices to refer to
   the slots?  That's a good question; ask the author.  I think it was
   the cognac.  */

#define SCM_SYMBOLP(x)		(SCM_NIMP (x) \
				 && (SCM_TYP7S (x) == scm_tc7_ssymbol))

#define SCM_LENGTH_MAX		(0xffffffL)
#define SCM_LENGTH(x)		(((unsigned long) SCM_CELL_WORD_0 (x)) >> 8)
#define SCM_SETLENGTH(x, v, t)	(SCM_SET_CELL_WORD_0 ((x), ((v) << 8) + (t)))

#define SCM_CHARS(x)		((char *) (SCM_CELL_WORD_1 (x)))
#define SCM_UCHARS(x)		((unsigned char *) (SCM_CELL_WORD_1 (x)))
#define SCM_SETCHARS(x, v)	(SCM_SET_CELL_WORD_1 ((x), (scm_bits_t) (v)))

#define SCM_SYMBOL_SLOTS	    4
#define SCM_SLOTS(x)		    ((scm_bits_t *) (* ((scm_bits_t *) SCM_CHARS (x) - 1)))
#define SCM_SYMBOL_FUNC(X)	    (SCM_PACK (SCM_SLOTS (X) [0]))
#define SCM_SET_SYMBOL_FUNC(X, v)   (SCM_SLOTS (X) [0] = SCM_UNPACK (v))
#define SCM_SYMBOL_PROPS(X)	    (SCM_PACK (SCM_SLOTS (X) [1]))
#define SCM_SET_SYMBOL_PROPS(X, v)  (SCM_SLOTS (X) [1] = SCM_UNPACK (v))
#define SCM_SYMBOL_HASH(X)	    (SCM_SLOTS (X) [2])

#define SCM_ROSTRINGP(x) (SCM_NIMP(x) && ((SCM_TYP7S(x)==scm_tc7_string) \
			  || (SCM_TYP7S(x) == scm_tc7_ssymbol)))
#define SCM_ROCHARS(x) ((char *)((SCM_TYP7(x) == scm_tc7_substring) \
			? SCM_INUM (SCM_CADR (x)) + SCM_CHARS (SCM_CDDR (x))  \
			: SCM_CHARS (x)))
#define SCM_ROUCHARS(x) ((unsigned char *) ((SCM_TYP7(x) == scm_tc7_substring) \
			 ? SCM_INUM (SCM_CADR (x)) + SCM_UCHARS (SCM_CDDR (x))\
			 : SCM_UCHARS (x)))
#define SCM_ROLENGTH(x) SCM_LENGTH (x)
#define SCM_SLOPPY_SUBSTRP(x) (SCM_TYP7(x) == scm_tc7_substring)
#define SCM_SUBSTRP(x) (SCM_NIMP(x) && SCM_SLOPPY_SUBSTRP(x))
#define SCM_SUBSTR_STR(x) (SCM_CDDR (x))
#define SCM_SUBSTR_OFFSET(x) (SCM_CADR (x))

#define SCM_COERCE_SUBSTR(x) { if (SCM_SUBSTRP (x)) \
				 x = scm_makfromstr (SCM_ROCHARS (x), \
						     SCM_ROLENGTH (x), 0); }



extern unsigned long scm_strhash (const unsigned char *str, scm_sizet len, unsigned long n);
extern SCM scm_sym2vcell (SCM sym, SCM thunk, SCM definep);
extern SCM scm_sym2ovcell_soft (SCM sym, SCM obarray);
extern SCM scm_sym2ovcell (SCM sym, SCM obarray);
extern SCM scm_intern_obarray_soft (const char *name, scm_sizet len, SCM obarray, int softness);
extern SCM scm_intern_obarray (const char *name, scm_sizet len, SCM obarray);
extern SCM scm_intern (const char *name, scm_sizet len);
extern SCM scm_intern0 (const char *name);
extern SCM scm_sysintern (const char *name, SCM val);
extern SCM scm_sysintern0 (const char *name);
extern SCM scm_sysintern0_no_module_lookup (const char *name);
extern SCM scm_symbol_value0 (const char *name);
extern SCM scm_symbol_p (SCM x);
extern SCM scm_symbol_to_string (SCM s);
extern SCM scm_string_to_symbol (SCM s);
extern SCM scm_string_to_obarray_symbol (SCM o, SCM s, SCM softp);
extern SCM scm_intern_symbol (SCM o, SCM s);
extern SCM scm_unintern_symbol (SCM o, SCM s);
extern SCM scm_symbol_binding (SCM o, SCM s);
extern SCM scm_symbol_interned_p (SCM o, SCM s);
extern SCM scm_symbol_bound_p (SCM o, SCM s);
extern SCM scm_symbol_set_x (SCM o, SCM s, SCM v);
extern SCM scm_symbol_fref (SCM s);
extern SCM scm_symbol_pref (SCM s);
extern SCM scm_symbol_fset_x (SCM s, SCM val);
extern SCM scm_symbol_pset_x (SCM s, SCM val);
extern SCM scm_symbol_hash (SCM s);
extern SCM scm_builtin_bindings (void);
extern SCM scm_builtin_weak_bindings (void);
extern SCM scm_gensym (SCM name, SCM obarray);
extern void scm_init_symbols (void);

extern int scm_can_use_top_level_lookup_closure_var;

#endif  /* SYMBOLSH */

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/
