libguile/struct.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_STRUCT_H
   4 #define SCM_STRUCT_H
   5
   6 /* Copyright (C) 1995,1997,1999,2000,2001, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 3 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  */
  23
  24 \f
  25
  26 #include "libguile/__scm.h"
  27 #include "libguile/print.h"
  28
  29 \f
  30
  31 /* The relationship between a struct and its vtable is a bit complicated,
  32    because we want structs to be used as GOOPS' native representation -- which
  33    in turn means we need support for changing the "class" (vtable) of an
  34    "instance" (struct). This necessitates some indirection and trickery.
  35
  36    I would like to write this all up here, but for now:
  37
  38      http://wingolog.org/archives/2009/11/09/class-redefinition-in-guile
  39  */
  40
  41 /* All vtables have the following fields. */
  42 #define SCM_VTABLE_BASE_LAYOUT                                          \
  43   "pr" /* layout */                                                     \
  44   "uh" /* flags */                                                      \
  45   "sr" /* self */                                                       \
  46   "uh" /* finalizer */                                                  \
  47   "pw" /* printer */                                                    \
  48   "ph" /* name (hidden from make-struct for back-compat reasons) */     \
  49   "uh" /* reserved */                                                   \
  50   "uh" /* reserved */
  51
  52 #define scm_vtable_index_layout            0 /* A symbol describing the physical arrangement of this type. */
  53 #define scm_vtable_index_flags             1 /* Class flags */
  54 #define scm_vtable_index_self              2 /* A pointer to the vtable itself */
  55 #define scm_vtable_index_instance_finalize 3 /* Finalizer for instances of this struct type. */
  56 #define scm_vtable_index_instance_printer  4 /* A printer for this struct type. */
  57 #define scm_vtable_index_name              5 /* Name of this vtable. */
  58 #define scm_vtable_index_reserved_6        6
  59 #define scm_vtable_index_reserved_7        7
  60 #define scm_vtable_offset_user             8 /* Where do user fields start in the vtable? */
  61
  62 /* All applicable structs have the following fields. */
  63 #define SCM_APPLICABLE_BASE_LAYOUT              \
  64   "pw" /* procedure */
  65 #define SCM_APPLICABLE_WITH_SETTER_BASE_LAYOUT  \
  66   "pw" /* procedure */                          \
  67   "pw" /* setter */
  68 #define scm_applicable_struct_index_procedure 0 /* The procedure of an applicable
  69                                                    struct. Only valid if the
  70                                                    struct's vtable has the
  71                                                    applicable flag set. */
  72 #define scm_applicable_struct_index_setter    1 /* The setter of an applicable
  73                                                    struct. Only valid if the
  74                                                    struct's vtable has the
  75                                                    setter flag set. */
  76
  77 #define SCM_VTABLE_FLAG_VTABLE (1L << 0) /* instances of this vtable are themselves vtables? */
  78 #define SCM_VTABLE_FLAG_APPLICABLE_VTABLE (1L << 1) /* instances of this vtable are applicable vtables? */
  79 #define SCM_VTABLE_FLAG_APPLICABLE (1L << 2) /* instances of this vtable are applicable? */
  80 #define SCM_VTABLE_FLAG_SETTER_VTABLE (1L << 3) /* instances of this vtable are applicable-with-setter vtables? */
  81 #define SCM_VTABLE_FLAG_SETTER (1L << 4) /* instances of this vtable are applicable-with-setters? */
  82 #define SCM_VTABLE_FLAG_RESERVED_0 (1L << 5)
  83 #define SCM_VTABLE_FLAG_RESERVED_1 (1L << 6)
  84 #define SCM_VTABLE_FLAG_RESERVED_2 (1L << 7)
  85 #define SCM_VTABLE_FLAG_GOOPS_0 (1L << 8)
  86 #define SCM_VTABLE_FLAG_GOOPS_1 (1L << 9)
  87 #define SCM_VTABLE_FLAG_GOOPS_2 (1L << 10)
  88 #define SCM_VTABLE_FLAG_GOOPS_3 (1L << 11)
  89 #define SCM_VTABLE_FLAG_GOOPS_4 (1L << 12)
  90 #define SCM_VTABLE_FLAG_GOOPS_5 (1L << 13)
  91 #define SCM_VTABLE_FLAG_GOOPS_6 (1L << 14)
  92 #define SCM_VTABLE_FLAG_GOOPS_7 (1L << 15)
  93 #define SCM_VTABLE_USER_FLAG_SHIFT 16
  94
  95 typedef void (*scm_t_struct_finalize) (SCM obj);
  96
  97 #define SCM_STRUCTP(X)                  (!SCM_IMP(X) && (SCM_TYP3(X) == scm_tc3_struct))
  98 #define SCM_STRUCT_SLOTS(X)             ((SCM*)SCM_CELL_WORD_1 ((X)))
  99 #define SCM_STRUCT_SLOT_REF(X,I)        (SCM_STRUCT_SLOTS (X)[(I)])
 100 #define SCM_STRUCT_SLOT_SET(X,I,V)      SCM_STRUCT_SLOTS (X)[(I)]=(V)
 101 #define SCM_STRUCT_DATA(X)              ((scm_t_bits*)SCM_CELL_WORD_1 (X))
 102 #define SCM_STRUCT_DATA_REF(X,I)        (SCM_STRUCT_DATA (X)[(I)])
 103 #define SCM_STRUCT_DATA_SET(X,I,V)      SCM_STRUCT_DATA (X)[(I)]=(V)
 104
 105 /* The SCM_VTABLE_* macros assume that you're passing them a struct which is a
 106    valid vtable. */
 107 #define SCM_VTABLE_LAYOUT(X)            (SCM_STRUCT_SLOT_REF ((X), scm_vtable_index_layout))
 108 #define SCM_SET_VTABLE_LAYOUT(X,L)      (SCM_STRUCT_SLOT_SET ((X), scm_vtable_index_layout, L))
 109 #define SCM_VTABLE_FLAGS(X)             (SCM_STRUCT_DATA_REF (X, scm_vtable_index_flags))
 110 #define SCM_SET_VTABLE_FLAGS(X,F)       (SCM_STRUCT_DATA_REF (X, scm_vtable_index_flags) |= (F))
 111 #define SCM_CLEAR_VTABLE_FLAGS(X,F)     (SCM_STRUCT_DATA_REF (X, scm_vtable_index_flags) &= (~(F)))
 112 #define SCM_VTABLE_FLAG_IS_SET(X,F)     (SCM_STRUCT_DATA_REF (X, scm_vtable_index_flags) & (F))
 113 #define SCM_VTABLE_INSTANCE_FINALIZER(X) ((scm_t_struct_finalize)SCM_STRUCT_SLOT_REF (X, scm_vtable_index_instance_finalize))
 114 #define SCM_VTABLE_INSTANCE_PRINTER(X)  (SCM_STRUCT_SLOT_REF (X, scm_vtable_index_instance_printer))
 115 #define SCM_VTABLE_NAME(X)              (SCM_STRUCT_SLOT_REF (X, scm_vtable_index_name))
 116 #define SCM_SET_VTABLE_NAME(X,V)        (SCM_STRUCT_SLOT_SET (X, scm_vtable_index_name, V))
 117
 118 /* Structs hold a pointer to their vtable's data, not the vtable itself. To get
 119    the vtable we have to do an indirection through the self slot. */
 120 #define SCM_STRUCT_VTABLE_DATA(X)       ((scm_t_bits*)(SCM_CELL_WORD_0 (X) - scm_tc3_struct))
 121 #define SCM_STRUCT_VTABLE_SLOTS(X)      ((SCM*)(SCM_CELL_WORD_0 (X) - scm_tc3_struct))
 122 #define SCM_STRUCT_VTABLE(X)            (SCM_STRUCT_VTABLE_SLOTS(X)[scm_vtable_index_self])
 123 /* But often we just need to access the vtable's data; we can do that without
 124    the data->self->data indirection. */
 125 #define SCM_STRUCT_LAYOUT(X)            (SCM_STRUCT_VTABLE_SLOTS (X)[scm_vtable_index_layout])
 126 #define SCM_STRUCT_PRINTER(X)           (SCM_STRUCT_VTABLE_SLOTS (X)[scm_vtable_index_instance_printer])
 127 #define SCM_STRUCT_FINALIZER(X)         ((scm_t_struct_finalize)SCM_STRUCT_VTABLE_DATA (X)[scm_vtable_index_instance_finalize])
 128 #define SCM_STRUCT_VTABLE_FLAGS(X)      (SCM_STRUCT_VTABLE_DATA (X)[scm_vtable_index_flags])
 129 #define SCM_STRUCT_VTABLE_FLAG_IS_SET(X,F) (SCM_STRUCT_VTABLE_DATA (X)[scm_vtable_index_flags]&(F))
 130
 131 #define SCM_STRUCT_APPLICABLE_P(X)      (SCM_STRUCT_VTABLE_FLAG_IS_SET ((X), SCM_VTABLE_FLAG_APPLICABLE))
 132 #define SCM_STRUCT_SETTER_P(X)          (SCM_STRUCT_VTABLE_FLAG_IS_SET ((X), SCM_VTABLE_FLAG_SETTER))
 133 #define SCM_STRUCT_PROCEDURE(X)         (SCM_STRUCT_SLOT_REF (X, scm_applicable_struct_index_procedure))
 134 #define SCM_SET_STRUCT_PROCEDURE(X,P)   (SCM_STRUCT_SLOT_SET (X, scm_applicable_struct_index_procedure, P))
 135 #define SCM_STRUCT_SETTER(X)            (SCM_STRUCT_SLOT_REF (X, scm_applicable_struct_index_setter))
 136 #define SCM_SET_STRUCT_SETTER(X,P)      (SCM_STRUCT_SLOT_SET (X, scm_applicable_struct_index_setter, P))
 137
 138 #define SCM_STRUCT_TABLE_NAME(X) SCM_CAR (X)
 139 #define SCM_SET_STRUCT_TABLE_NAME(X, NAME) SCM_SETCAR (X, NAME)
 140 #define SCM_STRUCT_TABLE_CLASS(X) SCM_CDR (X)
 141 #define SCM_SET_STRUCT_TABLE_CLASS(X, CLASS) SCM_SETCDR (X, CLASS)
 142 SCM_API SCM scm_struct_table;
 143
 144 SCM_API SCM scm_standard_vtable_vtable;
 145 SCM_API SCM scm_applicable_struct_vtable_vtable;
 146 SCM_API SCM scm_applicable_struct_with_setter_vtable_vtable;
 147
 148 \f
 149
 150 SCM_API SCM scm_make_struct_layout (SCM fields);
 151 SCM_API SCM scm_struct_p (SCM x);
 152 SCM_API SCM scm_struct_vtable_p (SCM x);
 153 SCM_API SCM scm_make_struct (SCM vtable, SCM tail_array_size, SCM init);
 154 SCM_API SCM scm_c_make_struct (SCM vtable, size_t n_tail, size_t n_inits,
 155                                scm_t_bits init, ...);
 156 SCM_API SCM scm_c_make_structv (SCM vtable, size_t n_tail, size_t n_inits,
 157                                 scm_t_bits init[]);
 158 SCM_API SCM scm_make_vtable (SCM fields, SCM printer);
 159 SCM_API SCM scm_make_vtable_vtable (SCM extra_fields, SCM tail_array_size, SCM init);
 160 SCM_API SCM scm_struct_ref (SCM handle, SCM pos);
 161 SCM_API SCM scm_struct_set_x (SCM handle, SCM pos, SCM val);
 162 SCM_API SCM scm_struct_vtable (SCM handle);
 163 SCM_API SCM scm_struct_vtable_tag (SCM handle);
 164 SCM_API SCM scm_struct_create_handle (SCM obj);
 165 SCM_API SCM scm_struct_vtable_name (SCM vtable);
 166 SCM_API SCM scm_set_struct_vtable_name_x (SCM vtable, SCM name);
 167 SCM_API void scm_print_struct (SCM exp, SCM port, scm_print_state *);
 168
 169 SCM_INTERNAL SCM scm_i_struct_equalp (SCM s1, SCM s2);
 170 SCM_INTERNAL unsigned long scm_struct_ihashq (SCM, unsigned long, void *);
 171 SCM_INTERNAL SCM scm_i_alloc_struct (scm_t_bits *vtable_data, int n_words, const char *what);
 172 SCM_INTERNAL void scm_i_struct_inherit_vtable_magic (SCM vtable, SCM obj);
 173 SCM_INTERNAL void scm_init_struct (void);
 174
 175 #endif  /* SCM_STRUCT_H */
 176
 177 /*
 178   Local Variables:
 179   c-file-style: "gnu"
 180   End:
 181 */