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 "kw.h"
  54
  55 #include "objects.h"
  56 \f
  57
  58 SCM scm_metaclass_standard;
  59 SCM scm_metaclass_operator;
  60
  61 /* These variables are filled in by the object system when loaded. */
  62 SCM scm_class_boolean, scm_class_char, scm_class_pair;
  63 SCM scm_class_procedure, scm_class_string, scm_class_symbol;
  64 SCM scm_class_vector, scm_class_null;
  65 SCM scm_class_real, scm_class_complex, scm_class_integer;
  66 SCM scm_class_keyword, scm_class_unknown;
  67
  68 void (*scm_change_object_class) (SCM, SCM, SCM);
  69
  70 /* This function is used for efficient type dispatch.  */
  71 SCM
  72 scm_class_of (SCM x)
  73 {
  74   switch (SCM_ITAG3 (x))
  75     {
  76     case scm_tc3_int_1:
  77     case scm_tc3_int_2:
  78       return scm_class_integer;
  79
  80     case scm_tc3_imm24:
  81       if (SCM_ICHRP (x))
  82         return scm_class_char;
  83       else
  84         {
  85           switch (SCM_ISYMNUM (x))
  86             {
  87             case SCM_ISYMNUM (SCM_BOOL_F):
  88             case SCM_ISYMNUM (SCM_BOOL_T):
  89               return scm_class_boolean;
  90             case SCM_ISYMNUM (SCM_EOL):
  91               return scm_class_null;
  92             default:
  93               return scm_class_unknown;
  94             }
  95         }
  96
  97     case scm_tc3_cons:
  98       switch (SCM_TYP7 (x))
  99         {
 100         case scm_tcs_cons_nimcar:
 101           return scm_class_pair;
 102         case scm_tcs_closures:
 103           return scm_class_procedure;
 104         case scm_tcs_symbols:
 105           return scm_class_symbol;
 106         case scm_tc7_vector:
 107         case scm_tc7_wvect:
 108         case scm_tc7_bvect:
 109         case scm_tc7_byvect:
 110         case scm_tc7_svect:
 111         case scm_tc7_ivect:
 112         case scm_tc7_uvect:
 113         case scm_tc7_fvect:
 114         case scm_tc7_dvect:
 115         case scm_tc7_cvect:
 116           return scm_class_vector;
 117         case scm_tc7_string:
 118         case scm_tc7_substring:
 119           return scm_class_string;
 120         case scm_tc7_asubr:
 121         case scm_tc7_subr_0:
 122         case scm_tc7_subr_1:
 123         case scm_tc7_cxr:
 124         case scm_tc7_subr_3:
 125         case scm_tc7_subr_2:
 126         case scm_tc7_rpsubr:
 127         case scm_tc7_subr_1o:
 128         case scm_tc7_subr_2o:
 129         case scm_tc7_lsubr_2:
 130         case scm_tc7_lsubr:
 131           return scm_class_procedure;
 132
 133         case scm_tc7_port:
 134           return scm_class_unknown;
 135         case scm_tc7_smob:
 136           {
 137             SCM type = SCM_TYP16 (x);
 138             if (type == scm_tc16_flo)
 139               {
 140                 if (SCM_CAR (x) & SCM_IMAG_PART)
 141                   return scm_class_complex;
 142                 else
 143                   return scm_class_real;
 144               }
 145             else if (type == scm_tc16_bigpos || type == scm_tc16_bigneg)
 146               return scm_class_integer;
 147             else if (type == scm_tc16_kw)
 148               return scm_class_keyword;
 149             else
 150               return scm_class_unknown;
 151           }
 152         case scm_tcs_cons_gloc:
 153           /* must be a struct */
 154           if (SCM_OBJ_CLASS_FLAGS (x) & SCM_CLASSF_GOOPS)
 155           {
 156             if (CLASS_REDEF (SCM_CLASS_OF (x)) != SCM_BOOL_F)
 157               scm_change_object_class (x,
 158                                        SCM_CLASS_OF (x),
 159                                        CLASS_REDEF (SCM_CLASS_OF (x)));
 160             return SCM_CLASS_OF (x);
 161           }
 162         default:
 163           if (SCM_CONSP (x))
 164             return scm_class_pair;
 165           else
 166             return scm_class_unknown;
 167         }
 168
 169     case scm_tc3_cons_gloc:
 170     case scm_tc3_tc7_1:
 171     case scm_tc3_tc7_2:
 172     case scm_tc3_closure:
 173       /* Never reached */
 174       break;
 175     }
 176   return scm_class_unknown;
 177 }
 178
 179 SCM_PROC (s_entity_p, "entity?", 1, 0, 0, scm_entity_p);
 180
 181 SCM
 182 scm_entity_p (SCM obj)
 183 {
 184   return (SCM_NIMP (obj) && SCM_STRUCTP (obj) && SCM_I_ENTITYP (obj)
 185           ? SCM_BOOL_T
 186           : SCM_BOOL_F);
 187 }
 188
 189 SCM_PROC (s_set_object_procedure_x, "set-object-procedure!", 1, 0, 1, scm_set_object_procedure_x);
 190
 191 SCM
 192 scm_set_object_procedure_x (SCM obj, SCM procs)
 193 {
 194   SCM proc[4], *pp, p, setp, arity;
 195   int i, a, r;
 196   SCM_ASSERT (SCM_NIMP (obj) && SCM_STRUCTP (obj)
 197               && ((SCM_CLASS_FLAGS (obj) & SCM_CLASSF_OPERATOR)
 198                   || SCM_I_ENTITYP (obj)),
 199               obj,
 200               SCM_ARG1,
 201               s_set_object_procedure_x);
 202   for (i = 0; i < 4; ++i)
 203     proc[i] = SCM_BOOL_F;
 204   i = 0;
 205   while (SCM_NIMP (procs))
 206     {
 207       if (i == 4)
 208         scm_wrong_num_args (scm_makfrom0str (s_set_object_procedure_x));
 209       p = SCM_CAR (procs);
 210       setp = 0;
 211       SCM_ASSERT (SCM_NIMP (p), p, SCM_ARG2 + i, s_set_object_procedure_x);
 212       if (SCM_CLOSUREP (p))
 213         {
 214           arity = scm_procedure_property (p, scm_sym_arity);
 215           a = SCM_INUM (SCM_CAR (arity));
 216           /* Closures have zero optional args */
 217           r = SCM_NFALSEP (SCM_CADDR (arity));
 218           if (a == 1 || (a <= 1 && r))
 219             {
 220               if (SCM_NFALSEP (proc[0]))
 221                 goto ambiguous;
 222               proc[0] = setp = p;
 223             }
 224           if (a == 2 || (a <= 2 && r))
 225             {
 226               if (SCM_NFALSEP (proc[1]))
 227                 goto ambiguous;
 228               proc[1] = setp = p;
 229             }
 230           if (a == 3 || (a <= 3 && r))
 231             {
 232               if (SCM_NFALSEP (proc[2]))
 233                 goto ambiguous;
 234               proc[2] = setp = p;
 235             }
 236           if (a <= 4 && r)
 237             {
 238               if (SCM_NFALSEP (proc[3]))
 239                 goto ambiguous;
 240               proc[3] = setp = p;
 241             }
 242         }
 243       else if (SCM_TYP7 (p) == scm_tc7_subr_1)
 244         {
 245           if (SCM_NFALSEP (proc[0]))
 246             goto ambiguous;
 247           proc[0] = setp = p;
 248         }
 249       else if (SCM_TYP7 (p) == scm_tc7_subr_2)
 250         {
 251           if (SCM_NFALSEP (proc[1]))
 252             goto ambiguous;
 253           proc[1] = setp = p;
 254         }
 255       else if (SCM_TYP7 (p) == scm_tc7_subr_3)
 256         {
 257           if (SCM_NFALSEP (proc[2]))
 258             goto ambiguous;
 259           proc[2] = setp = p;
 260         }
 261       else if (SCM_TYP7 (p) == scm_tc7_lsubr_2)
 262         {
 263           if (SCM_NFALSEP (proc[3]))
 264             {
 265             ambiguous:
 266               SCM_ASSERT (0, p, "Ambiguous procedure arities",
 267                           s_set_object_procedure_x);
 268             }
 269           proc[3] = setp = p;
 270         }
 271       SCM_ASSERT (setp, p, SCM_ARG2 + i, s_set_object_procedure_x);
 272       ++i;
 273       procs = SCM_CDR (procs);
 274     }
 275   pp = (SCM_I_ENTITYP (obj)
 276         ? &SCM_ENTITY_PROC_0 (obj)
 277         : &SCM_OPERATOR_CLASS (obj)->proc0);
 278   for (i = 0; i < 4; ++i)
 279     *pp++ = proc[i];
 280   return SCM_UNSPECIFIED;
 281 }
 282
 283 SCM
 284 scm_i_make_class_object (SCM meta,
 285                          SCM layout_string,
 286                          unsigned long flags)
 287 {
 288   SCM c;
 289   SCM layout = scm_make_struct_layout (layout_string);
 290   c = scm_make_struct (meta,
 291                        SCM_INUM0,
 292                        SCM_LIST4 (layout, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 293   SCM_SET_CLASS_FLAGS (c, flags);
 294   return c;
 295 }
 296
 297 SCM_PROC (s_make_class_object, "make-class-object", 2, 0, 0, scm_make_class_object);
 298
 299 SCM
 300 scm_make_class_object (SCM metaclass, SCM layout)
 301 {
 302   unsigned long flags = 0;
 303   SCM_ASSERT (SCM_NIMP (metaclass) && SCM_STRUCTP (metaclass),
 304               metaclass, SCM_ARG1, s_make_class_object);
 305   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 306               layout, SCM_ARG2, s_make_class_object);
 307   if (metaclass == scm_metaclass_operator)
 308     flags = SCM_CLASSF_OPERATOR;
 309   return scm_i_make_class_object (metaclass, layout, flags);
 310 }
 311
 312 SCM_PROC (s_make_subclass_object, "make-subclass-object", 2, 0, 0, scm_make_subclass_object);
 313
 314 SCM
 315 scm_make_subclass_object (SCM class, SCM layout)
 316 {
 317   SCM pl;
 318   SCM_ASSERT (SCM_NIMP (class) && SCM_STRUCTP (class),
 319               class,
 320               SCM_ARG1,
 321               s_make_subclass_object);
 322   SCM_ASSERT (SCM_NIMP (layout) && SCM_STRINGP (layout),
 323               layout,
 324               SCM_ARG2,
 325               s_make_subclass_object);
 326   pl = SCM_STRUCT_DATA (class)[scm_vtable_index_layout];
 327   /* Convert symbol->string */
 328   pl = scm_makfromstr (SCM_CHARS (pl), (scm_sizet) SCM_LENGTH (pl), 0);
 329   return scm_i_make_class_object (SCM_STRUCT_VTABLE (class),
 330                                   scm_string_append (SCM_LIST2 (pl, layout)),
 331                                   SCM_CLASS_FLAGS (class));
 332 }
 333
 334 void
 335 scm_init_objects ()
 336 {
 337   SCM ms = scm_makfrom0str (SCM_METACLASS_STANDARD_LAYOUT);
 338   SCM ml = scm_make_struct_layout (ms);
 339   SCM mt = scm_make_vtable_vtable (ml, SCM_INUM0,
 340                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 341
 342   SCM os = scm_makfrom0str (SCM_METACLASS_OPERATOR_LAYOUT);
 343   SCM ol = scm_make_struct_layout (os);
 344   SCM ot = scm_make_vtable_vtable (ol, SCM_INUM0,
 345                                    SCM_LIST3 (SCM_BOOL_F, SCM_EOL, SCM_EOL));
 346
 347   SCM es = scm_makfrom0str (SCM_ENTITY_LAYOUT);
 348   SCM el = scm_make_struct_layout (es);
 349   SCM et = scm_make_struct (mt, SCM_INUM0,
 350                             SCM_LIST4 (el, SCM_BOOL_F, SCM_EOL, SCM_EOL));
 351
 352   scm_sysintern ("<class>", mt);
 353   scm_metaclass_standard = mt;
 354   scm_sysintern ("<operator-class>", ot);
 355   scm_metaclass_operator = ot;
 356   SCM_SET_CLASS_FLAGS (et, SCM_CLASSF_OPERATOR | SCM_CLASSF_ENTITY);
 357   scm_sysintern ("<entity>", et);
 358
 359 #include "objects.x"
 360 }