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_smob_class = 0;
  71
  72 SCM (*scm_make_extended_class) (char *type_name);
  73 void (*scm_change_object_class) (SCM, SCM, SCM);
  74
  75 /* This function is used for efficient type dispatch.  */
  76 SCM
  77 scm_class_of (SCM x)
  78 {
  79   switch (SCM_ITAG3 (x))
  80     {
  81     case scm_tc3_int_1:
  82     case scm_tc3_int_2:
  83       return scm_class_integer;
  84
  85     case scm_tc3_imm24:
  86       if (SCM_ICHRP (x))
  87         return scm_class_char;
  88       else
  89         {
  90           switch (SCM_ISYMNUM (x))
  91             {
  92             case SCM_ISYMNUM (SCM_BOOL_F):
  93             case SCM_ISYMNUM (SCM_BOOL_T):
  94               return scm_class_boolean;
  95             case SCM_ISYMNUM (SCM_EOL):
  96               return scm_class_null;
  97             default:
  98               return scm_class_unknown;
  99             }
 100         }
 101
 102     case scm_tc3_cons:
 103       switch (SCM_TYP7 (x))
 104         {
 105         case scm_tcs_cons_nimcar:
 106           return scm_class_pair;
 107         case scm_tcs_closures:
 108           return scm_class_procedure;
 109         case scm_tcs_symbols:
 110           return scm_class_symbol;
 111         case scm_tc7_vector:
 112         case scm_tc7_wvect:
 113         case scm_tc7_bvect:
 114         case scm_tc7_byvect:
 115         case scm_tc7_svect:
 116         case scm_tc7_ivect:
 117         case scm_tc7_uvect:
 118         case scm_tc7_fvect:
 119         case scm_tc7_dvect:
 120         case scm_tc7_cvect:
 121           return scm_class_vector;
 122         case scm_tc7_string:
 123         case scm_tc7_substring:
 124           return scm_class_string;
 125         case scm_tc7_asubr:
 126         case scm_tc7_subr_0:
 127         case scm_tc7_subr_1:
 128         case scm_tc7_cxr:
 129         case scm_tc7_subr_3:
 130         case scm_tc7_subr_2:
 131         case scm_tc7_rpsubr:
 132         case scm_tc7_subr_1o:
 133         case scm_tc7_subr_2o:
 134         case scm_tc7_lsubr_2:
 135         case scm_tc7_lsubr:
 136         case scm_tc7_cclo:
 137           return scm_class_procedure;
 138         case scm_tc7_pws:
 139           return scm_class_procedure_with_setter;
 140
 141         case scm_tc7_port:
 142           return scm_class_unknown;
 143         case scm_tc7_smob:
 144           {
 145             SCM type = SCM_TYP16 (x);
 146             if (type == scm_tc16_flo)
 147               {
 148                 if (SCM_CAR (x) & SCM_IMAG_PART)
 149                   return scm_class_complex;
 150                 else
 151                   return scm_class_real;
 152               }
 153             else
 154               return scm_smob_class[SCM_TC2SMOBNUM (type)];
 155           }
 156         case scm_tcs_cons_gloc:
 157           /* must be a struct */
 158           if (SCM_OBJ_CLASS_FLAGS (x) & SCM_CLASSF_GOOPS)
 159             {
 160               /* Goops object */
 161               if (SCM_OBJ_CLASS_REDEF (x) != SCM_BOOL_F)
 162                 scm_change_object_class (x,
 163                                          SCM_CLASS_OF (x),         /* old */
 164                                          SCM_OBJ_CLASS_REDEF (x)); /* new */
 165               return SCM_CLASS_OF (x);
 166             }
 167           else
 168             {
 169               /* ordinary struct */
 170               SCM handle = scm_struct_create_handle (SCM_STRUCT_VTABLE (x));
 171               if (SCM_NFALSEP (SCM_STRUCT_TABLE_CLASS (SCM_CDR (handle))))
 172                 return SCM_STRUCT_TABLE_CLASS (SCM_CDR (handle));
 173               else
 174                 {
 175                   SCM name = SCM_STRUCT_TABLE_NAME (SCM_CDR (handle));
 176                   SCM class = scm_make_extended_class (SCM_NFALSEP (name)
 177                                                        ? SCM_ROCHARS (name)
 178                                                        : 0);
 179                   SCM_SET_STRUCT_TABLE_CLASS (handle, class);
 180                   return class;
 181                 }
 182             }
 183         default:
 184           if (SCM_CONSP (x))
 185             return scm_class_pair;
 186           else
 187             return scm_class_unknown;
 188         }
 189
 190     case scm_tc3_cons_gloc:
 191     case scm_tc3_tc7_1:
 192     case scm_tc3_tc7_2:
 193     case scm_tc3_closure:
 194       /* Never reached */
 195       break;
 196     }
 197   return scm_class_unknown;
 198 }
 199
 200 SCM_PROC (s_entity_p, "entity?", 1, 0, 0, scm_entity_p);
 201
 202 SCM
 203 scm_entity_p (SCM obj)
 204 {
 205   return (SCM_NIMP (obj) && SCM_STRUCTP (obj) && SCM_I_ENTITYP (obj)
 206           ? SCM_BOOL_T
 207           : SCM_BOOL_F);
 208 }
 209
 210 SCM_PROC (s_set_object_procedure_x, "set-object-procedure!", 1, 0, 1, scm_set_object_procedure_x);
 211
 212 SCM
 213 scm_set_object_procedure_x (SCM obj, SCM procs)
 214 {
 215   SCM proc[4], *pp, p, setp, arity;
 216   int i, a, r;
 217   SCM_ASSERT (SCM_NIMP (obj) && SCM_STRUCTP (obj)
 218               && ((SCM_CLASS_FLAGS (obj) & SCM_CLASSF_OPERATOR)
 219                   || SCM_I_ENTITYP (obj)),
 220               obj,
 221               SCM_ARG1,
 222               s_set_object_procedure_x);
 223   for (i = 0; i < 4; ++i)
 224     proc[i] = SCM_BOOL_F;
 225   i = 0;
 226   while (SCM_NIMP (procs))
 227     {
 228       if (i == 4)
 229         scm_wrong_num_args (scm_makfrom0str (s_set_object_procedure_x));
 230       p = SCM_CAR (procs);
 231       setp = 0;
 232       SCM_ASSERT (SCM_NIMP (p), p, SCM_ARG2 + i, s_set_object_procedure_x);
 233       if (SCM_CLOSUREP (p))
 234         {
 235           arity = scm_procedure_property (p, scm_sym_arity);
 236           a = SCM_INUM (SCM_CAR (arity));
 237           /* Closures have zero optional args */
 238           r = SCM_NFALSEP (SCM_CADDR (arity));
 239           if (a == 1 || (a <= 1 && r))
 240             {
 241               if (SCM_NFALSEP (proc[0]))
 242                 goto ambiguous;
 243               proc[0] = setp = p;
 244             }
 245           if (a == 2 || (a <= 2 && r))
 246             {
 247               if (SCM_NFALSEP (proc[1]))
 248                 goto ambiguous;
 249               proc[1] = setp = p;
 250             }
 251           if (a == 3 || (a <= 3 && r))
 252             {
 253               if (SCM_NFALSEP (proc[2]))
 254                 goto ambiguous;
 255               proc[2] = setp = p;
 256             }
 257           if (a <= 4 && r)
 258             {
 259               if (SCM_NFALSEP (proc[3]))
 260                 goto ambiguous;
 261               proc[3] = setp = p;
 262             }
 263         }
 264       else if (SCM_TYP7 (p) == scm_tc7_subr_1)
 265         {
 266           if (SCM_NFALSEP (proc[0]))
 267             goto ambiguous;
 268           proc[0] = setp = p;
 269         }
 270       else if (SCM_TYP7 (p) == scm_tc7_subr_2)
 271         {
 272           if (SCM_NFALSEP (proc[1]))
 273             goto ambiguous;
 274           proc[1] = setp = p;
 275         }
 276       else if (SCM_TYP7 (p) == scm_tc7_subr_3)
 277         {
 278           if (SCM_NFALSEP (proc[2]))
 279             goto ambiguous;
 280           proc[2] = setp = p;
 281         }
 282       else if (SCM_TYP7 (p) == scm_tc7_lsubr_2)
 283         {
 284           if (SCM_NFALSEP (proc[3]))
 285             {
 286             ambiguous:
 287               SCM_ASSERT (0, p, "Ambiguous procedure arities",
 288                           s_set_object_procedure_x);
 289             }
 290           proc[3] = setp = p;
 291         }
 292       SCM_ASSERT (setp, p, SCM_ARG2 + i, s_set_object_procedure_x);
 293       ++i;
 294       procs = SCM_CDR (procs);
 295     }
 296   pp = (SCM_I_ENTITYP (obj)
 297         ? &SCM_ENTITY_PROC_0 (obj)
 298         : &SCM_OPERATOR_CLASS (obj)->proc0);
 299   for (i = 0; i < 4; ++i)
 300     *pp++ = proc[i];
 301   return SCM_UNSPECIFIED;
 302 }
 303
 304 /* The following procedures are not a part of Goops but a minimal
 305  * object system built upon structs.  They are here for those who
 306  * want to implement their own object system.
 307  */
 308
 309 SCM
 310 scm_i_make_class_object (SCM meta,
 311                          SCM layout_string,
 312                          unsigned long flags)
 313 {
 314   SCM c;
 315   SCM layout = scm_make_struct_layout (layout_string);
 316   c = scm_make_struct (meta,
 317                        SCM_INUM0,
 318                        SCM_LIST4 (layout, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 319   SCM_SET_CLASS_FLAGS (c, flags);
 320   return c;
 321 }
 322
 323 SCM_PROC (s_make_class_object, "make-class-object", 2, 0, 0, scm_make_class_object);
 324
 325 SCM
 326 scm_make_class_object (SCM metaclass, SCM layout)
 327 {
 328   unsigned long flags = 0;
 329   SCM_ASSERT (SCM_NIMP (metaclass) && SCM_STRUCTP (metaclass),
 330               metaclass, SCM_ARG1, s_make_class_object);
 331   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 332               layout, SCM_ARG2, s_make_class_object);
 333   if (metaclass == scm_metaclass_operator)
 334     flags = SCM_CLASSF_OPERATOR;
 335   return scm_i_make_class_object (metaclass, layout, flags);
 336 }
 337
 338 SCM_PROC (s_make_subclass_object, "make-subclass-object", 2, 0, 0, scm_make_subclass_object);
 339
 340 SCM
 341 scm_make_subclass_object (SCM class, SCM layout)
 342 {
 343   SCM pl;
 344   SCM_ASSERT (SCM_NIMP (class) && SCM_STRUCTP (class),
 345               class,
 346               SCM_ARG1,
 347               s_make_subclass_object);
 348   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 349               layout,
 350               SCM_ARG2,
 351               s_make_subclass_object);
 352   pl = SCM_STRUCT_DATA (class)[scm_vtable_index_layout];
 353   /* Convert symbol->string */
 354   pl = scm_makfromstr (SCM_CHARS (pl), (scm_sizet) SCM_LENGTH (pl), 0);
 355   return scm_i_make_class_object (SCM_STRUCT_VTABLE (class),
 356                                   scm_string_append (SCM_LIST2 (pl, layout)),
 357                                   SCM_CLASS_FLAGS (class));
 358 }
 359
 360 void
 361 scm_init_objects ()
 362 {
 363   SCM ms = scm_makfrom0str (SCM_METACLASS_STANDARD_LAYOUT);
 364   SCM ml = scm_make_struct_layout (ms);
 365   SCM mt = scm_make_vtable_vtable (ml, SCM_INUM0,
 366                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 367
 368   SCM os = scm_makfrom0str (SCM_METACLASS_OPERATOR_LAYOUT);
 369   SCM ol = scm_make_struct_layout (os);
 370   SCM ot = scm_make_vtable_vtable (ol, SCM_INUM0,
 371                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 372
 373   SCM es = scm_makfrom0str (SCM_ENTITY_LAYOUT);
 374   SCM el = scm_make_struct_layout (es);
 375   SCM et = scm_make_struct (mt, SCM_INUM0,
 376                             SCM_LIST4 (el, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 377
 378   scm_sysintern ("<class>", mt);
 379   scm_metaclass_standard = mt;
 380   scm_sysintern ("<operator-class>", ot);
 381   scm_metaclass_operator = ot;
 382   SCM_SET_CLASS_FLAGS (et, SCM_CLASSF_OPERATOR | SCM_CLASSF_ENTITY);
 383   SCM_SET_CLASS_DESTRUCTOR (et, scm_struct_free_entity);
 384   scm_sysintern ("<entity>", et);
 385
 386 #include "objects.x"
 387 }