libguile/procs.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_PROCS_H
   4 #define SCM_PROCS_H
   5 /* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this software; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307 USA
  21  *
  22  * As a special exception, the Free Software Foundation gives permission
  23  * for additional uses of the text contained in its release of GUILE.
  24  *
  25  * The exception is that, if you link the GUILE library with other files
  26  * to produce an executable, this does not by itself cause the
  27  * resulting executable to be covered by the GNU General Public License.
  28  * Your use of that executable is in no way restricted on account of
  29  * linking the GUILE library code into it.
  30  *
  31  * This exception does not however invalidate any other reasons why
  32  * the executable file might be covered by the GNU General Public License.
  33  *
  34  * This exception applies only to the code released by the
  35  * Free Software Foundation under the name GUILE.  If you copy
  36  * code from other Free Software Foundation releases into a copy of
  37  * GUILE, as the General Public License permits, the exception does
  38  * not apply to the code that you add in this way.  To avoid misleading
  39  * anyone as to the status of such modified files, you must delete
  40  * this exception notice from them.
  41  *
  42  * If you write modifications of your own for GUILE, it is your choice
  43  * whether to permit this exception to apply to your modifications.
  44  * If you do not wish that, delete this exception notice.  */
  45
  46 \f
  47
  48 #include "libguile/__scm.h"
  49
  50 \f
  51
  52
  53 /* Subrs
  54  */
  55
  56 typedef struct
  57 {
  58   SCM handle;                   /* link back to procedure object */
  59   SCM name;
  60   SCM *generic;                 /* 0 if no generic support
  61                                  * *generic == 0 until first method
  62                                  */
  63   SCM properties;               /* procedure properties */
  64 } scm_t_subr_entry;
  65
  66 #if (SCM_DEBUG_DEPRECATED == 0)
  67 # define scm_subr_entry scm_t_subr_entry
  68 #endif
  69
  70 #define SCM_SUBRNUM(subr) (SCM_CELL_WORD_0 (subr) >> 8)
  71 #define SCM_SET_SUBRNUM(subr, num) \
  72         SCM_SET_CELL_WORD_0 (subr, (num << 8) + SCM_TYP7 (subr))
  73 #define SCM_SUBR_ENTRY(x) (scm_subr_table[SCM_SUBRNUM (x)])
  74 #define SCM_SNAME(x) (SCM_SUBR_ENTRY (x).name)
  75 #define SCM_SUBRF(x) ((SCM (*)()) SCM_CELL_WORD_1 (x))
  76 #define SCM_SET_SUBRF(x, v) (SCM_SET_CELL_WORD_1 ((x), (v)))
  77 #define SCM_DSUBRF(x) ((double (*)()) SCM_CELL_WORD_1 (x))
  78 #define SCM_SUBR_PROPS(x) (SCM_SUBR_ENTRY (x).properties)
  79 #define SCM_SUBR_GENERIC(x) (SCM_SUBR_ENTRY (x).generic)
  80
  81 #define SCM_CCLO_LENGTH(x) (SCM_CELL_WORD_0 (x) >> 8)
  82 #define SCM_SET_CCLO_LENGTH(x, v) (SCM_SET_CELL_WORD_0 ((x), ((v) << 8) + scm_tc7_cclo))
  83 #define SCM_CCLO_BASE(x) ((scm_t_bits *) SCM_CELL_WORD_1 (x))
  84 #define SCM_SET_CCLO_BASE(x, v) (SCM_SET_CELL_WORD_1 ((x), (v)))
  85
  86 #define SCM_CCLO_REF(x, i) (SCM_PACK (SCM_CCLO_BASE (x) [i]))
  87 #define SCM_CCLO_SET(x, i, v) (SCM_CCLO_BASE (x) [i] = SCM_UNPACK (v))
  88
  89 #define SCM_CCLO_SUBR(x) (SCM_CCLO_REF ((x), 0))
  90 #define SCM_SET_CCLO_SUBR(x, v) (SCM_CCLO_SET ((x), 0, (v)))
  91
  92 /* Closures
  93  */
  94
  95 #define SCM_CLOSUREP(x) (SCM_NIMP(x) && (SCM_TYP3 (x) == scm_tc3_closure))
  96 #define SCM_CLOSCAR(x) SCM_PACK (SCM_CELL_WORD_0 (x) - scm_tc3_closure)
  97 #define SCM_CODE(x) SCM_CAR (SCM_CLOSCAR (x))
  98 #define SCM_CLOSURE_FORMALS(x) SCM_CAR (SCM_CODE (x))
  99 #define SCM_PROCPROPS(x) SCM_CDR (SCM_CLOSCAR (x))
 100 #define SCM_SETPROCPROPS(x, p) SCM_SETCDR (SCM_CLOSCAR (x), p)
 101 #define SCM_SETCODE(x, e) (SCM_SET_CELL_WORD_0 (x, SCM_UNPACK (scm_cons ((e), SCM_EOL)) \
 102                            + scm_tc3_closure))
 103 #define SCM_ENV(x) SCM_CELL_OBJECT_1 (x)
 104 #define SCM_SETENV(x, e) SCM_SET_CELL_OBJECT_1 ((x), (e))
 105 #define SCM_TOP_LEVEL(ENV)  (SCM_NULLP (ENV) || (SCM_EQ_P (scm_procedure_p (SCM_CAR (ENV)), SCM_BOOL_T)))
 106
 107 /* Procedure-with-setter
 108
 109    Four representations for procedure-with-setters were
 110    considered before selecting this one:
 111
 112    1. A closure where the CODE and ENV slots are used to represent
 113    the getter and a new SETTER slot is used for the setter.  The
 114    original getter is stored as a `getter' procedure property.  For
 115    closure getters, the CODE and ENV slots contains a copy of the
 116    getter's CODE and ENV slots.  For subr getters, the CODE contains
 117    a call to the subr.
 118
 119    2. A compiled closure with a call to the getter in the cclo
 120    procedure.  The getter and setter are stored in slots 1 and 2.
 121
 122    3. An entity (i.e. a struct with an associated procedure) with a
 123    call to the getter in the entity procedure and the setter stored
 124    in slot 0.  The original getter is stored in slot 1.
 125
 126    4. A new primitive procedure type supported in the evaluator.  The
 127    getter and setter are stored in a GETTER and SETTER slot.  A call
 128    to this procedure type results in a retrieval of the getter and a
 129    jump back to the correct eval dispatcher.
 130
 131    Representation 4 was selected because of efficiency and
 132    simplicity.
 133
 134    Rep 1 has the advantage that there is zero penalty for closure
 135    getters, but primitive getters will get considerable overhead
 136    because the procedure-with-getter will be a closure which calls
 137    the getter.
 138
 139    Rep 3 has the advantage that a GOOPS accessor can be a subclass of
 140    <procedure-with-setter>, but together with rep 2 it suffers from a
 141    three level dispatch for non-GOOPS getters:
 142
 143      cclo/struct --> dispatch proc --> getter
 144
 145    This is because the dispatch procedure must take an extra initial
 146    argument (cclo for rep 2, struct for rep 3).
 147
 148    Rep 4 has the single disadvantage that it uses up one tc7 type
 149    code, but the plan for uniform vectors will very likely free tc7
 150    codes, so this is probably no big problem.  Also note that the
 151    GETTER and SETTER slots can live directly on the heap, using the
 152    new four-word cells.  */
 153
 154 #define SCM_PROCEDURE_WITH_SETTER_P(obj) (SCM_NIMP(obj) && (SCM_TYP7 (obj) == scm_tc7_pws))
 155 #define SCM_PROCEDURE(obj) SCM_CELL_OBJECT_1 (obj)
 156 #define SCM_SETTER(obj) SCM_CELL_OBJECT_2 (obj)
 157
 158 extern scm_t_subr_entry *scm_subr_table;
 159 extern long scm_subr_table_size;
 160 extern long scm_subr_table_room;
 161
 162 \f
 163
 164 extern void scm_mark_subr_table (void);
 165 extern void scm_free_subr_entry (SCM subr);
 166 extern SCM scm_c_make_subr (const char *name, long type, SCM (*fcn)());
 167 extern SCM scm_c_make_subr_with_generic (const char *name, long type,
 168                                          SCM (*fcn)(), SCM *gf);
 169 extern SCM scm_c_define_subr (const char *name, long type, SCM (*fcn)());
 170 extern SCM scm_c_define_subr_with_generic (const char *name, long type,
 171                                            SCM (*fcn)(), SCM *gf);
 172 extern SCM scm_makcclo (SCM proc, size_t len);
 173 extern SCM scm_procedure_p (SCM obj);
 174 extern SCM scm_closure_p (SCM obj);
 175 extern SCM scm_thunk_p (SCM obj);
 176 extern int scm_subr_p (SCM obj);
 177 extern SCM scm_procedure_documentation (SCM proc);
 178 extern SCM scm_procedure_with_setter_p (SCM obj);
 179 extern SCM scm_make_procedure_with_setter (SCM procedure, SCM setter);
 180 extern SCM scm_procedure (SCM proc);
 181 extern SCM scm_setter (SCM proc);
 182 extern void scm_init_subr_table (void);
 183 extern void scm_init_procs (void);
 184
 185 #ifdef GUILE_DEBUG
 186 extern SCM scm_make_cclo (SCM proc, SCM len);
 187 #endif /*GUILE_DEBUG*/
 188
 189 \f
 190
 191 #if (SCM_DEBUG_DEPRECATED == 0)
 192
 193 #define SCM_SUBR_DOC(x) SCM_BOOL_F
 194
 195 extern SCM scm_make_subr (const char *name, int type, SCM (*fcn) ());
 196 extern SCM scm_make_subr_with_generic (const char *name,
 197                                        int type,
 198                                        SCM (*fcn) (),
 199                                        SCM *gf);
 200 extern SCM scm_make_subr_opt (const char *name,
 201                               int type,
 202                               SCM (*fcn) (),
 203                               int set);
 204
 205 #endif  /* SCM_DEBUG_DEPRECATED == 0 */
 206
 207 #endif  /* SCM_PROCS_H */
 208
 209 /*
 210   Local Variables:
 211   c-file-style: "gnu"
 212   End:
 213 */