6 /* Copyright (C) 1996, 1999 Free Software Foundation, Inc.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this software; see the file COPYING. If not, write to
20 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
21 * Boston, MA 02111-1307 USA
23 * As a special exception, the Free Software Foundation gives permission
24 * for additional uses of the text contained in its release of GUILE.
26 * The exception is that, if you link the GUILE library with other files
27 * to produce an executable, this does not by itself cause the
28 * resulting executable to be covered by the GNU General Public License.
29 * Your use of that executable is in no way restricted on account of
30 * linking the GUILE library code into it.
32 * This exception does not however invalidate any other reasons why
33 * the executable file might be covered by the GNU General Public License.
35 * This exception applies only to the code released by the
36 * Free Software Foundation under the name GUILE. If you copy
37 * code from other Free Software Foundation releases into a copy of
38 * GUILE, as the General Public License permits, the exception does
39 * not apply to the code that you add in this way. To avoid misleading
40 * anyone as to the status of such modified files, you must delete
41 * this exception notice from them.
43 * If you write modifications of your own for GUILE, it is your choice
44 * whether to permit this exception to apply to your modifications.
45 * If you do not wish that, delete this exception notice. */
48 /* This file and objects.c contains those minimal pieces of the Guile
49 * Object Oriented Programming System which need to be included in
52 * {Objects and structs}
54 * Objects are currently based upon structs. Although the struct
55 * implementation will change thoroughly in the future, objects will
56 * still be based upon structs.
59 #include "libguile/__scm.h"
60 #include "libguile/struct.h"
66 * These are used for efficient identification of instances of a
67 * certain class or its subclasses when traversal of the inheritance
68 * graph would be too costly.
70 #define SCM_CLASS_FLAGS(class) SCM_ASWORD(SCM_STRUCT_DATA (class)[scm_struct_i_flags])
71 #define SCM_OBJ_CLASS_FLAGS(obj)\
72 SCM_ASWORD(SCM_STRUCT_VTABLE_DATA (obj)[scm_struct_i_flags])
73 #define SCM_SET_CLASS_FLAGS(c, f) (SCM_CLASS_FLAGS (c) |= (f))
74 #define SCM_CLEAR_CLASS_FLAGS(c, f) (SCM_CLASS_FLAGS (c) &= ~(f))
75 #define SCM_CLASSF_MASK SCM_STRUCTF_MASK
77 #define SCM_CLASSF_ENTITY SCM_STRUCTF_ENTITY
78 /* Operator classes need to be identified in the evaluator.
79 (Entities also have SCM_CLASSF_OPERATOR set in their vtable.) */
80 #define SCM_CLASSF_OPERATOR (1L << 29)
82 #define SCM_I_OPERATORP(obj)\
83 ((SCM_OBJ_CLASS_FLAGS (obj) & SCM_CLASSF_OPERATOR) != 0)
84 #define SCM_OPERATOR_CLASS(obj)\
85 ((struct scm_metaclass_operator *) SCM_STRUCT_DATA (obj))
86 #define SCM_OBJ_OPERATOR_CLASS(obj)\
87 ((struct scm_metaclass_operator *) SCM_STRUCT_VTABLE_DATA (obj))
88 #define SCM_OPERATOR_PROCEDURE(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->procedure)
89 #define SCM_OPERATOR_SETTER(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->setter)
91 #define SCM_I_ENTITYP(obj)\
92 ((SCM_OBJ_CLASS_FLAGS (obj) & SCM_CLASSF_ENTITY) != 0)
93 #define SCM_ENTITY_PROCEDURE(obj) \
94 (SCM_STRUCT_DATA (obj)[scm_struct_i_procedure])
95 #define SCM_ENTITY_SETTER(obj) (SCM_STRUCT_DATA (obj)[scm_struct_i_setter])
97 #define SCM_SET_CLASS_DESTRUCTOR(c, d) SCM_SET_VTABLE_DESTRUCTOR (c, d)
98 #define SCM_SET_CLASS_INSTANCE_SIZE(c, s) \
99 (SCM_STRUCT_DATA (c)[scm_struct_i_size] \
100 = (SCM_STRUCT_DATA (c)[scm_struct_i_size] & SCM_STRUCTF_MASK) | s)
102 /* {Operator classes}
104 * Instances of operator classes can work as operators, i. e., they
105 * can be applied to arguments just as if they were ordinary
108 * For instances of operator classes, the procedures to be applied are
109 * stored in four dedicated slots in the associated class object.
110 * Which one is selected depends on the number of arguments in the
113 * If zero arguments are passed, the first will be selected.
114 * If one argument is passed, the second will be selected.
115 * If two arguments are passed, the third will be selected.
116 * If three or more arguments are passed, the fourth will be selected.
118 * This is complicated and may seem gratuitous but has to do with the
119 * architecture of the evaluator. Using only one procedure would
120 * result in a great deal less efficient application, loss of
121 * tail-recursion and would be difficult to reconcile with the
122 * debugging evaluator.
124 * Also, using this "forked" application in low-level code has the
125 * advantage of speeding up some code. An example is method dispatch
126 * for generic operators applied to few arguments. On the user level,
127 * the "forked" application will be hidden by mechanisms in the GOOPS
130 * Operator classes have the metaclass <operator-metaclass>.
132 * An example of an operator class is the class <tk-command>.
134 #define SCM_METACLASS_STANDARD_LAYOUT ""
135 struct scm_metaclass_standard
{
142 #define SCM_METACLASS_OPERATOR_LAYOUT "popo"
143 struct scm_metaclass_operator
{
154 * For instances of entity classes (entities), the procedures to be
155 * applied are stored in the instance itself rather than in the class
156 * object as is the case for instances of operator classes (see above).
158 * An example of an entity class is the class of generic methods.
160 #define SCM_ENTITY_LAYOUT ""
162 /* {Interface to Goops}
164 * The evaluator contains a multi-method dispatch mechanism.
165 * This interface is used by that mechanism and during creation of
166 * smob and struct classes.
169 /* Internal representation of Goops objects. */
170 #define SCM_CLASSF_PURE_GENERIC (0x010 << 20)
171 #define SCM_CLASSF_GOOPS_VALID (0x080 << 20)
172 #define SCM_CLASSF_GOOPS (0x100 << 20)
173 #define scm_si_redefined 6
174 #define scm_si_hashsets 7
175 #define SCM_CLASS_OF(x) SCM_STRUCT_VTABLE (x)
176 #define SCM_OBJ_CLASS_REDEF(x) (SCM_STRUCT_VTABLE_DATA(x)[scm_si_redefined])
178 typedef struct scm_effective_slot_definition
{
182 SCM (*get
) (SCM obj
, SCM slotdef
);
183 SCM (*set
) (SCM obj
, SCM slotdef
, SCM value
);
184 } scm_effective_slot_definition
;
186 #define SCM_ESLOTDEF(x) ((scm_effective_slot_definition *) SCM_CDR (x))
188 #define SCM_CMETHOD_CODE(cmethod) SCM_CDR (cmethod)
189 #define SCM_CMETHOD_ENV(cmethod) SCM_CAR (cmethod)
192 #define SCM_IN_PCLASS_INDEX 0x000
193 #define SCM_OUT_PCLASS_INDEX 0x100
194 #define SCM_INOUT_PCLASS_INDEX 0x200
196 /* Plugin proxy classes for basic types. */
197 extern SCM scm_metaclass_standard
;
198 extern SCM scm_metaclass_operator
;
199 extern SCM scm_class_boolean
, scm_class_char
, scm_class_pair
;
200 extern SCM scm_class_procedure
, scm_class_string
, scm_class_symbol
;
201 extern SCM scm_class_procedure_with_setter
, scm_class_primitive_generic
;
202 extern SCM scm_class_vector
, scm_class_null
;
203 extern SCM scm_class_real
, scm_class_complex
, scm_class_integer
;
204 extern SCM scm_class_unknown
;
205 extern SCM
*scm_port_class
;
206 extern SCM
*scm_smob_class
;
208 extern SCM scm_no_applicable_method
;
210 /* Plugin Goops functions. */
211 extern SCM (*scm_make_extended_class
) (char *type_name
);
212 extern void (*scm_make_port_classes
) (int ptobnum
, char *type_name
);
213 extern void (*scm_change_object_class
) (SCM
, SCM
, SCM
);
214 extern SCM (*scm_memoize_method
) (SCM x
, SCM args
);
216 extern SCM
scm_class_of (SCM obj
);
217 extern SCM
scm_mcache_lookup_cmethod (SCM cache
, SCM args
);
218 extern SCM
scm_mcache_compute_cmethod (SCM cache
, SCM args
);
219 extern SCM
scm_call_generic_0 (SCM gf
);
220 /* The following are declared in __scm.h
221 extern SCM scm_call_generic_1 (SCM gf, SCM a1);
222 extern SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
224 extern SCM
scm_call_generic_3 (SCM gf
, SCM a1
, SCM a2
, SCM a3
);
225 extern SCM
scm_apply_generic (SCM gf
, SCM args
);
226 extern SCM
scm_entity_p (SCM obj
);
227 extern SCM
scm_operator_p (SCM obj
);
228 extern SCM
scm_set_object_procedure_x (SCM obj
, SCM procs
);
230 extern SCM
scm_object_procedure (SCM obj
);
232 extern SCM
scm_make_class_object (SCM metaclass
, SCM layout
);
233 extern SCM
scm_make_subclass_object (SCM c
, SCM layout
);
235 extern SCM
scm_i_make_class_object (SCM metaclass
, SCM layout_string
,
236 unsigned long flags
);
237 extern void scm_init_objects (void);
239 #endif /* OBJECTSH */