libguile/objects.c

   1 /*      Copyright (C) 1995,1996 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41 \f
  42
  43 /* This file and objects.h contains those minimal pieces of the Guile
  44  * Object Oriented Programming System which need to be included in
  45  * libguile.  See the comments in objects.h.
  46  */
  47
  48 #include "_scm.h"
  49
  50 #include "struct.h"
  51 #include "procprop.h"
  52 #include "chars.h"
  53 #include "keywords.h"
  54 #include "smob.h"
  55
  56 #include "objects.h"
  57 \f
  58
  59 SCM scm_metaclass_standard;
  60 SCM scm_metaclass_operator;
  61
  62 /* These variables are filled in by the object system when loaded. */
  63 SCM scm_class_boolean, scm_class_char, scm_class_pair;
  64 SCM scm_class_procedure, scm_class_string, scm_class_symbol;
  65 SCM scm_class_procedure_with_setter;
  66 SCM scm_class_vector, scm_class_null;
  67 SCM scm_class_integer, scm_class_real, scm_class_complex;
  68 SCM scm_class_unknown;
  69
  70 SCM *scm_port_class = 0;
  71 SCM *scm_smob_class = 0;
  72
  73 SCM scm_apply_generic_env;
  74
  75 SCM (*scm_make_extended_class) (char *type_name);
  76 void (*scm_make_port_classes) (int ptobnum, char *type_name);
  77 void (*scm_change_object_class) (SCM, SCM, SCM);
  78
  79 /* This function is used for efficient type dispatch.  */
  80 SCM
  81 scm_class_of (SCM x)
  82 {
  83   switch (SCM_ITAG3 (x))
  84     {
  85     case scm_tc3_int_1:
  86     case scm_tc3_int_2:
  87       return scm_class_integer;
  88
  89     case scm_tc3_imm24:
  90       if (SCM_ICHRP (x))
  91         return scm_class_char;
  92       else
  93         {
  94           switch (SCM_ISYMNUM (x))
  95             {
  96             case SCM_ISYMNUM (SCM_BOOL_F):
  97             case SCM_ISYMNUM (SCM_BOOL_T):
  98               return scm_class_boolean;
  99             case SCM_ISYMNUM (SCM_EOL):
 100               return scm_class_null;
 101             default:
 102               return scm_class_unknown;
 103             }
 104         }
 105
 106     case scm_tc3_cons:
 107       switch (SCM_TYP7 (x))
 108         {
 109         case scm_tcs_cons_nimcar:
 110           return scm_class_pair;
 111         case scm_tcs_closures:
 112           return scm_class_procedure;
 113         case scm_tcs_symbols:
 114           return scm_class_symbol;
 115         case scm_tc7_vector:
 116         case scm_tc7_wvect:
 117         case scm_tc7_bvect:
 118         case scm_tc7_byvect:
 119         case scm_tc7_svect:
 120         case scm_tc7_ivect:
 121         case scm_tc7_uvect:
 122         case scm_tc7_fvect:
 123         case scm_tc7_dvect:
 124         case scm_tc7_cvect:
 125           return scm_class_vector;
 126         case scm_tc7_string:
 127         case scm_tc7_substring:
 128           return scm_class_string;
 129         case scm_tc7_asubr:
 130         case scm_tc7_subr_0:
 131         case scm_tc7_subr_1:
 132         case scm_tc7_cxr:
 133         case scm_tc7_subr_3:
 134         case scm_tc7_subr_2:
 135         case scm_tc7_rpsubr:
 136         case scm_tc7_subr_1o:
 137         case scm_tc7_subr_2o:
 138         case scm_tc7_lsubr_2:
 139         case scm_tc7_lsubr:
 140         case scm_tc7_cclo:
 141           return scm_class_procedure;
 142         case scm_tc7_pws:
 143           return scm_class_procedure_with_setter;
 144
 145         case scm_tc7_smob:
 146           {
 147             SCM type = SCM_TYP16 (x);
 148             if (type == scm_tc16_flo)
 149               {
 150                 if (SCM_CAR (x) & SCM_IMAG_PART)
 151                   return scm_class_complex;
 152                 else
 153                   return scm_class_real;
 154               }
 155             else if (type != scm_tc16_port_with_ps)
 156               return scm_smob_class[SCM_TC2SMOBNUM (type)];
 157             x = SCM_PORT_WITH_PS_PORT (x);
 158             /* fall through to ports */
 159           }
 160         case scm_tc7_port:
 161           return scm_port_class[(SCM_WRTNG & SCM_CAR (x)
 162                                  ? (SCM_RDNG & SCM_CAR (x)
 163                                     ? SCM_INOUT_PCLASS_INDEX | SCM_PTOBNUM (x)
 164                                     : SCM_OUT_PCLASS_INDEX | SCM_PTOBNUM (x))
 165                                  : SCM_IN_PCLASS_INDEX | SCM_PTOBNUM (x))];
 166         case scm_tcs_cons_gloc:
 167           /* must be a struct */
 168           if (SCM_OBJ_CLASS_FLAGS (x) & SCM_CLASSF_GOOPS_VALID)
 169             return SCM_CLASS_OF (x);
 170           else if (SCM_OBJ_CLASS_FLAGS (x) & SCM_CLASSF_GOOPS)
 171             {
 172               /* Goops object */
 173               if (SCM_OBJ_CLASS_REDEF (x) != SCM_BOOL_F)
 174                 scm_change_object_class (x,
 175                                          SCM_CLASS_OF (x),         /* old */
 176                                          SCM_OBJ_CLASS_REDEF (x)); /* new */
 177               return SCM_CLASS_OF (x);
 178             }
 179           else
 180             {
 181               /* ordinary struct */
 182               SCM handle = scm_struct_create_handle (SCM_STRUCT_VTABLE (x));
 183               if (SCM_NFALSEP (SCM_STRUCT_TABLE_CLASS (SCM_CDR (handle))))
 184                 return SCM_STRUCT_TABLE_CLASS (SCM_CDR (handle));
 185               else
 186                 {
 187                   SCM name = SCM_STRUCT_TABLE_NAME (SCM_CDR (handle));
 188                   SCM class = scm_make_extended_class (SCM_NFALSEP (name)
 189                                                        ? SCM_ROCHARS (name)
 190                                                        : 0);
 191                   SCM_SET_STRUCT_TABLE_CLASS (handle, class);
 192                   return class;
 193                 }
 194             }
 195         default:
 196           if (SCM_CONSP (x))
 197             return scm_class_pair;
 198           else
 199             return scm_class_unknown;
 200         }
 201
 202     case scm_tc3_cons_gloc:
 203     case scm_tc3_tc7_1:
 204     case scm_tc3_tc7_2:
 205     case scm_tc3_closure:
 206       /* Never reached */
 207       break;
 208     }
 209   return scm_class_unknown;
 210 }
 211
 212 SCM_PROC (s_entity_p, "entity?", 1, 0, 0, scm_entity_p);
 213
 214 SCM
 215 scm_entity_p (SCM obj)
 216 {
 217   return (SCM_NIMP (obj) && SCM_STRUCTP (obj) && SCM_I_ENTITYP (obj)
 218           ? SCM_BOOL_T
 219           : SCM_BOOL_F);
 220 }
 221
 222 SCM_PROC (s_operator_p, "operator?", 1, 0, 0, scm_operator_p);
 223
 224 SCM
 225 scm_operator_p (SCM obj)
 226 {
 227   return (SCM_NIMP (obj)
 228           && SCM_STRUCTP (obj)
 229           && SCM_I_OPERATORP (obj)
 230           && !SCM_I_ENTITYP (obj)
 231           ? SCM_BOOL_T
 232           : SCM_BOOL_F);
 233 }
 234
 235 SCM_PROC (s_set_object_procedure_x, "set-object-procedure!", 1, 0, 1, scm_set_object_procedure_x);
 236
 237 SCM_SYMBOL (scm_sym_atdispatch, "@dispatch");
 238
 239 SCM
 240 scm_set_object_procedure_x (SCM obj, SCM procs)
 241 {
 242   SCM proc[4], *pp, p, setp, arity;
 243   int i, a, r;
 244   SCM_ASSERT (SCM_NIMP (obj) && SCM_STRUCTP (obj)
 245               && ((SCM_CLASS_FLAGS (obj) & SCM_CLASSF_OPERATOR)
 246                   || (SCM_I_ENTITYP (obj)
 247                       && !(SCM_OBJ_CLASS_FLAGS (obj)
 248                            & SCM_CLASSF_PURE_GENERIC))),
 249               obj,
 250               SCM_ARG1,
 251               s_set_object_procedure_x);
 252   for (i = 0; i < 4; ++i)
 253     proc[i] = SCM_BOOL_F;
 254   i = 0;
 255   while (SCM_NIMP (procs))
 256     {
 257       if (i == 4)
 258         scm_wrong_num_args (scm_makfrom0str (s_set_object_procedure_x));
 259       p = SCM_CAR (procs);
 260       setp = 0;
 261       SCM_ASSERT (SCM_NIMP (p), p, SCM_ARG2 + i, s_set_object_procedure_x);
 262       if (SCM_CLOSUREP (p))
 263         {
 264           arity = scm_procedure_property (p, scm_sym_arity);
 265           a = SCM_INUM (SCM_CAR (arity));
 266           /* Closures have zero optional args */
 267           r = SCM_NFALSEP (SCM_CADDR (arity));
 268           if (a == 1 || (a <= 1 && r))
 269             {
 270               if (SCM_NFALSEP (proc[0]))
 271                 goto ambiguous;
 272               proc[0] = setp = p;
 273             }
 274           if (a == 2 || (a <= 2 && r))
 275             {
 276               if (SCM_NFALSEP (proc[1]))
 277                 goto ambiguous;
 278               proc[1] = setp = p;
 279             }
 280           if (a == 3 || (a <= 3 && r))
 281             {
 282               if (SCM_NFALSEP (proc[2]))
 283                 goto ambiguous;
 284               proc[2] = setp = p;
 285             }
 286           if (a <= 4 && r)
 287             {
 288               if (SCM_NFALSEP (proc[3]))
 289                 goto ambiguous;
 290               proc[3] = setp = p;
 291             }
 292         }
 293       else if (SCM_TYP7 (p) == scm_tc7_subr_1)
 294         {
 295           if (SCM_NFALSEP (proc[0]))
 296             goto ambiguous;
 297           proc[0] = setp = p;
 298         }
 299       else if (SCM_TYP7 (p) == scm_tc7_subr_2)
 300         {
 301           if (SCM_NFALSEP (proc[1]))
 302             goto ambiguous;
 303           proc[1] = setp = p;
 304         }
 305       else if (SCM_TYP7 (p) == scm_tc7_subr_3)
 306         {
 307           if (SCM_NFALSEP (proc[2]))
 308             goto ambiguous;
 309           proc[2] = setp = p;
 310         }
 311       else if (SCM_TYP7 (p) == scm_tc7_lsubr_2)
 312         {
 313           if (SCM_NFALSEP (proc[3]))
 314             {
 315             ambiguous:
 316               SCM_ASSERT (0, p, "Ambiguous procedure arities",
 317                           s_set_object_procedure_x);
 318             }
 319           proc[3] = setp = p;
 320         }
 321       SCM_ASSERT (setp, p, SCM_ARG2 + i, s_set_object_procedure_x);
 322       ++i;
 323       procs = SCM_CDR (procs);
 324     }
 325   pp = (SCM_I_ENTITYP (obj)
 326         ? &SCM_ENTITY_PROC_0 (obj)
 327         : &SCM_OPERATOR_CLASS (obj)->proc0);
 328   for (i = 0; i < 4; ++i)
 329     *pp++ = proc[i];
 330   return SCM_UNSPECIFIED;
 331 }
 332
 333 #ifdef GUILE_DEBUG
 334 SCM_PROC (s_object_procedures, "object-procedures", 1, 0, 0, scm_object_procedures);
 335
 336 SCM
 337 scm_object_procedures (SCM obj)
 338 {
 339   SCM_ASSERT (SCM_NIMP (obj) && SCM_STRUCTP (obj) && SCM_I_OPERATORP (obj),
 340               obj, SCM_ARG1, s_object_procedures);
 341   return (SCM_I_ENTITYP (obj)
 342           ? SCM_LIST4 (SCM_ENTITY_PROC_0 (obj),
 343                        SCM_ENTITY_PROC_1 (obj),
 344                        SCM_ENTITY_PROC_2 (obj),
 345                        SCM_ENTITY_PROC_3 (obj))
 346           : SCM_LIST4 (SCM_OPERATOR_PROC_0 (obj),
 347                        SCM_OPERATOR_PROC_1 (obj),
 348                        SCM_OPERATOR_PROC_2 (obj),
 349                        SCM_OPERATOR_PROC_3 (obj)));
 350 }
 351 #endif /* GUILE_DEBUG */
 352
 353 /* The following procedures are not a part of Goops but a minimal
 354  * object system built upon structs.  They are here for those who
 355  * want to implement their own object system.
 356  */
 357
 358 SCM
 359 scm_i_make_class_object (SCM meta,
 360                          SCM layout_string,
 361                          unsigned long flags)
 362 {
 363   SCM c;
 364   SCM layout = scm_make_struct_layout (layout_string);
 365   c = scm_make_struct (meta,
 366                        SCM_INUM0,
 367                        SCM_LIST4 (layout, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 368   SCM_SET_CLASS_FLAGS (c, flags);
 369   return c;
 370 }
 371
 372 SCM_PROC (s_make_class_object, "make-class-object", 2, 0, 0, scm_make_class_object);
 373
 374 SCM
 375 scm_make_class_object (SCM metaclass, SCM layout)
 376 {
 377   unsigned long flags = 0;
 378   SCM_ASSERT (SCM_NIMP (metaclass) && SCM_STRUCTP (metaclass),
 379               metaclass, SCM_ARG1, s_make_class_object);
 380   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 381               layout, SCM_ARG2, s_make_class_object);
 382   if (metaclass == scm_metaclass_operator)
 383     flags = SCM_CLASSF_OPERATOR;
 384   return scm_i_make_class_object (metaclass, layout, flags);
 385 }
 386
 387 SCM_PROC (s_make_subclass_object, "make-subclass-object", 2, 0, 0, scm_make_subclass_object);
 388
 389 SCM
 390 scm_make_subclass_object (SCM class, SCM layout)
 391 {
 392   SCM pl;
 393   SCM_ASSERT (SCM_NIMP (class) && SCM_STRUCTP (class),
 394               class,
 395               SCM_ARG1,
 396               s_make_subclass_object);
 397   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 398               layout,
 399               SCM_ARG2,
 400               s_make_subclass_object);
 401   pl = SCM_STRUCT_DATA (class)[scm_vtable_index_layout];
 402   /* Convert symbol->string */
 403   pl = scm_makfromstr (SCM_CHARS (pl), (scm_sizet) SCM_LENGTH (pl), 0);
 404   return scm_i_make_class_object (SCM_STRUCT_VTABLE (class),
 405                                   scm_string_append (SCM_LIST2 (pl, layout)),
 406                                   SCM_CLASS_FLAGS (class));
 407 }
 408
 409 void
 410 scm_init_objects ()
 411 {
 412   SCM ms = scm_makfrom0str (SCM_METACLASS_STANDARD_LAYOUT);
 413   SCM ml = scm_make_struct_layout (ms);
 414   SCM mt = scm_make_vtable_vtable (ml, SCM_INUM0,
 415                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 416
 417   SCM os = scm_makfrom0str (SCM_METACLASS_OPERATOR_LAYOUT);
 418   SCM ol = scm_make_struct_layout (os);
 419   SCM ot = scm_make_vtable_vtable (ol, SCM_INUM0,
 420                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 421
 422   SCM es = scm_makfrom0str (SCM_ENTITY_LAYOUT);
 423   SCM el = scm_make_struct_layout (es);
 424   SCM et = scm_make_struct (mt, SCM_INUM0,
 425                             SCM_LIST4 (el, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 426
 427   scm_sysintern ("<class>", mt);
 428   scm_metaclass_standard = mt;
 429   scm_sysintern ("<operator-class>", ot);
 430   scm_metaclass_operator = ot;
 431   SCM_SET_CLASS_FLAGS (et, SCM_CLASSF_OPERATOR | SCM_CLASSF_ENTITY);
 432   SCM_SET_CLASS_DESTRUCTOR (et, scm_struct_free_entity);
 433   scm_sysintern ("<entity>", et);
 434
 435 #include "objects.x"
 436 }