libguile/properties.c

   1 /* Copyright (C) 1995,1996,2000,2001, 2003, 2006, 2008 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 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include "libguile/_scm.h"
  25 #include "libguile/hashtab.h"
  26 #include "libguile/alist.h"
  27 #include "libguile/root.h"
  28 #include "libguile/weaks.h"
  29 #include "libguile/validate.h"
  30 #include "libguile/eval.h"
  31
  32 #include "libguile/properties.h"
  33 \f
  34
  35 /* {Properties}
  36  */
  37
  38 SCM_DEFINE (scm_primitive_make_property, "primitive-make-property", 1, 0, 0,
  39             (SCM not_found_proc),
  40             "Create a @dfn{property token} that can be used with\n"
  41             "@code{primitive-property-ref} and @code{primitive-property-set!}.\n"
  42             "See @code{primitive-property-ref} for the significance of\n"
  43             "@var{not_found_proc}.")
  44 #define FUNC_NAME s_scm_primitive_make_property
  45 {
  46   if (not_found_proc != SCM_BOOL_F)
  47     SCM_VALIDATE_PROC (SCM_ARG1, not_found_proc);
  48   return scm_cons (not_found_proc, SCM_EOL);
  49 }
  50 #undef FUNC_NAME
  51
  52
  53 SCM_DEFINE (scm_primitive_property_ref, "primitive-property-ref", 2, 0, 0,
  54             (SCM prop, SCM obj),
  55             "Return the property @var{prop} of @var{obj}.\n"
  56             "\n"
  57             "When no value has yet been associated with @var{prop} and\n"
  58             "@var{obj}, the @var{not-found-proc} from @var{prop} is used.  A\n"
  59             "call @code{(@var{not-found-proc} @var{prop} @var{obj})} is made\n"
  60             "and the result set as the property value.  If\n"
  61             "@var{not-found-proc} is @code{#f} then @code{#f} is the\n"
  62             "property value.")
  63 #define FUNC_NAME s_scm_primitive_property_ref
  64 {
  65   SCM h;
  66
  67   SCM_VALIDATE_CONS (SCM_ARG1, prop);
  68
  69   h = scm_hashq_get_handle (scm_properties_whash, obj);
  70   if (scm_is_true (h))
  71     {
  72       SCM assoc = scm_assq (prop, SCM_CDR (h));
  73       if (scm_is_true (assoc))
  74         return SCM_CDR (assoc);
  75     }
  76
  77   if (scm_is_false (SCM_CAR (prop)))
  78     return SCM_BOOL_F;
  79   else
  80     {
  81       SCM val = scm_call_2 (SCM_CAR (prop), prop, obj);
  82       if (scm_is_false (h))
  83         h = scm_hashq_create_handle_x (scm_properties_whash, obj, SCM_EOL);
  84       SCM_SETCDR (h, scm_acons (prop, val, SCM_CDR (h)));
  85       return val;
  86     }
  87 }
  88 #undef FUNC_NAME
  89
  90
  91 SCM_DEFINE (scm_primitive_property_set_x, "primitive-property-set!", 3, 0, 0,
  92             (SCM prop, SCM obj, SCM val),
  93             "Set the property @var{prop} of @var{obj} to @var{val}.")
  94 #define FUNC_NAME s_scm_primitive_property_set_x
  95 {
  96   SCM h, assoc;
  97   SCM_VALIDATE_CONS (SCM_ARG1, prop);
  98   h = scm_hashq_create_handle_x (scm_properties_whash, obj, SCM_EOL);
  99   assoc = scm_assq (prop, SCM_CDR (h));
 100   if (SCM_NIMP (assoc))
 101     SCM_SETCDR (assoc, val);
 102   else
 103     {
 104       assoc = scm_acons (prop, val, SCM_CDR (h));
 105       SCM_SETCDR (h, assoc);
 106     }
 107   return SCM_UNSPECIFIED;
 108 }
 109 #undef FUNC_NAME
 110
 111
 112 SCM_DEFINE (scm_primitive_property_del_x, "primitive-property-del!", 2, 0, 0,
 113             (SCM prop, SCM obj),
 114             "Remove any value associated with @var{prop} and @var{obj}.")
 115 #define FUNC_NAME s_scm_primitive_property_del_x
 116 {
 117   SCM h;
 118   SCM_VALIDATE_CONS (SCM_ARG1, prop);
 119   h = scm_hashq_get_handle (scm_properties_whash, obj);
 120   if (scm_is_true (h))
 121     SCM_SETCDR (h, scm_assq_remove_x (SCM_CDR (h), prop));
 122   return SCM_UNSPECIFIED;
 123 }
 124 #undef FUNC_NAME
 125
 126
 127 void
 128 scm_init_properties ()
 129 {
 130   scm_properties_whash = scm_make_weak_key_hash_table (SCM_UNDEFINED);
 131 #include "libguile/properties.x"
 132 }
 133
 134
 135 /*
 136   Local Variables:
 137   c-file-style: "gnu"
 138   End:
 139 */