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* eval.c (SCM_CEVAL, scm_apply): Completed GOOPS support code;

Browse source 
Some indentation fixes.

* objects.h (SCM_METACLASS_STANDARD_LAYOUT): Printer field is no
longer a user field; New field: class_flags.

* objets.c, objects.h: New metaclass: scm_metaclass_operator.
This commit is contained in:
Mikael Djurfeldt 1997-10-12 12:54:54 +00:00
parent e0d86ad2fb
commit da7f71d7d5
4 changed files with 301 additions and 80 deletions
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112
libguile/objects.h
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@ -45,20 +45,92 @@
* If you do not wish that, delete this exception notice. */
/* This file and objects.c contains those minimal pieces of the Guile
* Object Oriented Programming System which need to be included in
* libguile.
*
* {Objects and structs}
*
* Objects are currently based upon structs. Although the struct
* implementation will change thoroughly in the future, objects will
* still be based upon structs.
*/
#include "libguile/__scm.h"
#include "libguile/struct.h"
#define SCM_I_ENTITYP(OBJ)\
(SCM_STRUCT_VTABLE_DATA (OBJ) == scm_entity_vtable)
#define SCM_ENTITY(OBJ) ((scm_entity*) SCM_STRUCT_DATA (OBJ))
#define SCM_ENTITY_PROC_0(OBJ) (SCM_ENTITY (OBJ)->proc0)
#define SCM_ENTITY_PROC_1(OBJ) (SCM_ENTITY (OBJ)->proc1)
#define SCM_ENTITY_PROC_2(OBJ) (SCM_ENTITY (OBJ)->proc2)
#define SCM_ENTITY_PROC_3(OBJ) (SCM_ENTITY (OBJ)->proc3)
/* {Class flags}
*
* These are used for efficient identification of instances of a
* certain class or its subclasses when traversal of the inheritance
* graph would be too costly.
*/
#define SCM_CLASS_FLAGS(class) (SCM_STRUCT_DATA (class)[scm_struct_i_tag])
#define SCM_OBJ_CLASS_FLAGS(obj)\
(SCM_STRUCT_VTABLE_DATA (obj)[scm_struct_i_tag])
#define SCM_SET_CLASS_FLAGS(c, f) (SCM_CLASS_FLAGS (c) |= (f))
#define SCM_CLEAR_CLASS_FLAGS(c, f) (SCM_CLASS_FLAGS (c) &= ~(f))
#define SCM_CLASSF_MASK (0xFF << 24)
#define SCM_METACLASS_STANDARD_LAYOUT "pwpwpw"
/* Operator classes need to be identified in the evaluator. */
#define SCM_CLASSF_OPERATOR (1L << 30)
/* Entities also have SCM_CLASSF_OPERATOR set in their vtable. */
#define SCM_CLASSF_ENTITY (1L << 29)
#define SCM_I_OPERATORP(obj)\
((SCM_OBJ_CLASS_FLAGS (obj) & SCM_CLASSF_OPERATOR) != 0)
#define SCM_OPERATOR_CLASS(obj)\
((struct scm_metaclass_operator *) SCM_STRUCT_DATA (obj))
#define SCM_OBJ_OPERATOR_CLASS(obj)\
((struct scm_metaclass_operator *) SCM_STRUCT_VTABLE_DATA (obj))
#define SCM_OPERATOR_PROC_0(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->proc0)
#define SCM_OPERATOR_PROC_1(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->proc1)
#define SCM_OPERATOR_PROC_2(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->proc2)
#define SCM_OPERATOR_PROC_3(obj) (SCM_OBJ_OPERATOR_CLASS (obj)->proc3)
#define SCM_I_ENTITYP(obj)\
((SCM_OBJ_CLASS_FLAGS (obj) & SCM_CLASSF_ENTITY) != 0)
#define SCM_ENTITY(obj) ((scm_entity*) SCM_STRUCT_DATA (obj))
#define SCM_ENTITY_PROC_0(obj) (SCM_ENTITY (obj)->proc0)
#define SCM_ENTITY_PROC_1(obj) (SCM_ENTITY (obj)->proc1)
#define SCM_ENTITY_PROC_2(obj) (SCM_ENTITY (obj)->proc2)
#define SCM_ENTITY_PROC_3(obj) (SCM_ENTITY (obj)->proc3)
/* {Operator classes}
*
* Instances of operator classes can work as operators, i. e., they
* can be applied to arguments just as if they were ordinary
* procedures.
*
* For instances of operator classes, the procedures to be applied are
* stored in four dedicated slots in the associated class object.
* Which one is selected depends on the number of arguments in the
* application.
*
* If zero arguments are passed, the first will be selected.
* If one argument is passed, the second will be selected.
* If two arguments are passed, the third will be selected.
* If three or more arguments are passed, the fourth will be selected.
*
* This is complicated and may seem gratuitous but has to do with the
* architecture of the evaluator. Using only one procedure would
* result in a great deal less efficient application, loss of
* tail-recursion and would be difficult to reconcile with the
* debugging evaluator.
*
* Also, using this "forked" application in low-level code has the
* advantage of speeding up some code. An example is method dispatch
* for generic operators applied to few arguments. On the user level,
* the "forked" application will be hidden by mechanisms in the GOOPS
* package.
*
* Operator classes have the metaclass <operator-metaclass>.
*
* An example of an operator class is the class <tk-command>.
*/
#define SCM_METACLASS_STANDARD_LAYOUT "pwpw"
struct scm_metaclass_standard {
SCM layout;
SCM vcell;
@ -68,6 +140,28 @@ struct scm_metaclass_standard {
SCM direct_slots;
};
#define SCM_METACLASS_OPERATOR_LAYOUT "pwpwpwpwpwpw"
struct scm_metaclass_operator {
SCM layout;
SCM vcell;
SCM vtable;
SCM print;
SCM direct_supers;
SCM direct_slots;
SCM proc0;
SCM proc1;
SCM proc2;
SCM proc3;
};
/* {Entity classes}
*
* For instances of entity classes (entities), the procedures to be
* applied are stored in the instance itself rather than in the class
* object as is the case for instances of operator classes (see above).
*
* An example of an entity class is the class of generic methods.
*/
#define SCM_ENTITY_LAYOUT "pwpwpwpw"
typedef struct scm_entity {
SCM proc0;
@ -77,7 +171,7 @@ typedef struct scm_entity {
} scm_entity;
extern SCM scm_metaclass_standard;
extern SCM *scm_entity_vtable;
extern SCM scm_metaclass_operator;
extern void scm_init_objects SCM_P ((void));