libguile/properties.c

   1 /* Copyright (C) 1995,1996,2000,2001, 2003, 2006 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library 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 GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18
  19 \f
  20
  21 #include "libguile/_scm.h"
  22 #include "libguile/hashtab.h"
  23 #include "libguile/alist.h"
  24 #include "libguile/root.h"
  25 #include "libguile/weaks.h"
  26 #include "libguile/validate.h"
  27 #include "libguile/eval.h"
  28
  29 #include "libguile/properties.h"
  30 \f
  31
  32 /* {Properties}
  33  */
  34
  35 SCM_DEFINE (scm_primitive_make_property, "primitive-make-property", 1, 0, 0,
  36             (SCM not_found_proc),
  37             "Create a @dfn{property token} that can be used with\n"
  38             "@code{primitive-property-ref} and @code{primitive-property-set!}.\n"
  39             "See @code{primitive-property-ref} for the significance of\n"
  40             "@var{not_found_proc}.")
  41 #define FUNC_NAME s_scm_primitive_make_property
  42 {
  43   if (not_found_proc != SCM_BOOL_F)
  44     SCM_VALIDATE_PROC (SCM_ARG1, not_found_proc);
  45   return scm_cons (not_found_proc, SCM_EOL);
  46 }
  47 #undef FUNC_NAME
  48
  49
  50 SCM_DEFINE (scm_primitive_property_ref, "primitive-property-ref", 2, 0, 0,
  51             (SCM prop, SCM obj),
  52             "Return the property @var{prop} of @var{obj}.\n"
  53             "\n"
  54             "When no value has yet been associated with @var{prop} and\n"
  55             "@var{obj}, the @var{not-found-proc} from @var{prop} is used.  A\n"
  56             "call @code{(@var{not-found-proc} @var{prop} @var{obj})} is made\n"
  57             "and the result set as the property value.  If\n"
  58             "@var{not-found-proc} is @code{#f} then @code{#f} is the\n"
  59             "property value.")
  60 #define FUNC_NAME s_scm_primitive_property_ref
  61 {
  62   SCM h;
  63
  64   SCM_VALIDATE_CONS (SCM_ARG1, prop);
  65
  66   h = scm_hashq_get_handle (scm_properties_whash, obj);
  67   if (scm_is_true (h))
  68     {
  69       SCM assoc = scm_assq (prop, SCM_CDR (h));
  70       if (scm_is_true (assoc))
  71         return SCM_CDR (assoc);
  72     }
  73
  74   if (scm_is_false (SCM_CAR (prop)))
  75     return SCM_BOOL_F;
  76   else
  77     {
  78       SCM val = scm_call_2 (SCM_CAR (prop), prop, obj);
  79       if (scm_is_false (h))
  80         h = scm_hashq_create_handle_x (scm_properties_whash, obj, SCM_EOL);
  81       SCM_SETCDR (h, scm_acons (prop, val, SCM_CDR (h)));
  82       return val;
  83     }
  84 }
  85 #undef FUNC_NAME
  86
  87
  88 SCM_DEFINE (scm_primitive_property_set_x, "primitive-property-set!", 3, 0, 0,
  89             (SCM prop, SCM obj, SCM val),
  90             "Set the property @var{prop} of @var{obj} to @var{val}.")
  91 #define FUNC_NAME s_scm_primitive_property_set_x
  92 {
  93   SCM h, assoc;
  94   SCM_VALIDATE_CONS (SCM_ARG1, prop);
  95   h = scm_hashq_create_handle_x (scm_properties_whash, obj, SCM_EOL);
  96   assoc = scm_assq (prop, SCM_CDR (h));
  97   if (SCM_NIMP (assoc))
  98     SCM_SETCDR (assoc, val);
  99   else
 100     {
 101       assoc = scm_acons (prop, val, SCM_CDR (h));
 102       SCM_SETCDR (h, assoc);
 103     }
 104   return SCM_UNSPECIFIED;
 105 }
 106 #undef FUNC_NAME
 107
 108
 109 SCM_DEFINE (scm_primitive_property_del_x, "primitive-property-del!", 2, 0, 0,
 110             (SCM prop, SCM obj),
 111             "Remove any value associated with @var{prop} and @var{obj}.")
 112 #define FUNC_NAME s_scm_primitive_property_del_x
 113 {
 114   SCM h;
 115   SCM_VALIDATE_CONS (SCM_ARG1, prop);
 116   h = scm_hashq_get_handle (scm_properties_whash, obj);
 117   if (scm_is_true (h))
 118     SCM_SETCDR (h, scm_assq_remove_x (SCM_CDR (h), prop));
 119   return SCM_UNSPECIFIED;
 120 }
 121 #undef FUNC_NAME
 122
 123
 124 void
 125 scm_init_properties ()
 126 {
 127   scm_properties_whash = scm_make_weak_key_hash_table (SCM_UNDEFINED);
 128 #include "libguile/properties.x"
 129 }
 130
 131
 132 /*
 133   Local Variables:
 134   c-file-style: "gnu"
 135   End:
 136 */