libguile/modules.c

   1 /*      Copyright (C) 1998, 2000 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
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include "libguile/_scm.h"
  48
  49 #include "libguile/eval.h"
  50 #include "libguile/procprop.h"
  51 #include "libguile/vectors.h"
  52 #include "libguile/hashtab.h"
  53 #include "libguile/struct.h"
  54 #include "libguile/variable.h"
  55
  56 #include "libguile/modules.h"
  57
  58 static SCM the_root_module;
  59 static SCM root_module_closure;
  60 static SCM scm_module_closure;
  61
  62 SCM
  63 scm_the_root_module ()
  64 {
  65   return SCM_CDR (the_root_module);
  66 }
  67
  68 static SCM the_module;
  69
  70 SCM
  71 scm_selected_module ()
  72 {
  73   return SCM_CDR (the_module);
  74 }
  75
  76 static SCM set_current_module;
  77
  78 SCM
  79 scm_select_module (SCM module)
  80 {
  81   SCM old = scm_selected_module ();
  82   scm_apply (SCM_CDR (set_current_module), SCM_LIST1 (module), SCM_EOL);
  83   return old;
  84 }
  85
  86 SCM_SYMBOL (scm_sym_app, "app");
  87 SCM_SYMBOL (scm_sym_modules, "modules");
  88 static SCM module_prefix;
  89
  90 static SCM
  91 scm_module_full_name (SCM name)
  92 {
  93   if (SCM_EQ_P (SCM_CAR (name), scm_sym_app))
  94     return name;
  95   else
  96     return scm_append (SCM_LIST2 (module_prefix, name));
  97 }
  98
  99 static SCM make_modules_in;
 100 static SCM beautify_user_module_x;
 101
 102 SCM
 103 scm_make_module (SCM name)
 104 {
 105   return scm_apply (SCM_CDR (make_modules_in),
 106                     SCM_LIST2 (scm_the_root_module (),
 107                                scm_module_full_name (name)),
 108                     SCM_EOL);
 109 }
 110
 111 SCM
 112 scm_ensure_user_module (SCM module)
 113 {
 114   scm_apply (SCM_CDR (beautify_user_module_x), SCM_LIST1 (module), SCM_EOL);
 115   return SCM_UNSPECIFIED;
 116 }
 117
 118 static SCM module_eval_closure;
 119
 120 SCM
 121 scm_module_lookup_closure (SCM module)
 122 {
 123   return scm_apply (SCM_CDR (module_eval_closure),
 124                     SCM_LIST1 (module),
 125                     SCM_EOL);
 126 }
 127
 128 static SCM resolve_module;
 129
 130 SCM
 131 scm_resolve_module (SCM name)
 132 {
 133   return scm_apply (SCM_CDR (resolve_module), SCM_LIST1 (name), SCM_EOL);
 134 }
 135
 136 static SCM try_module_autoload;
 137
 138 SCM
 139 scm_load_scheme_module (SCM name)
 140 {
 141   return scm_apply (SCM_CDR (try_module_autoload), SCM_LIST1 (name), SCM_EOL);
 142 }
 143
 144 /* Environments
 145  */
 146
 147 SCM
 148 scm_top_level_env (SCM thunk)
 149 {
 150   if (SCM_IMP (thunk))
 151     return SCM_EOL;
 152   else
 153     return scm_cons (thunk, SCM_EOL);
 154 }
 155
 156 SCM
 157 scm_env_top_level (SCM env)
 158 {
 159   while (SCM_NIMP (env))
 160     {
 161       if (!SCM_CONSP (SCM_CAR (env))
 162           && SCM_NFALSEP (scm_procedure_p (SCM_CAR (env))))
 163         return SCM_CAR(env);
 164       env = SCM_CDR (env);
 165     }
 166   return SCM_BOOL_F;
 167 }
 168
 169
 170 SCM_SYMBOL (scm_sym_system_module, "system-module");
 171
 172 SCM
 173 scm_system_module_env_p (SCM env)
 174 {
 175   SCM proc = scm_env_top_level (env);
 176   if (SCM_FALSEP (proc))
 177     proc = SCM_CDR (root_module_closure);
 178   return ((SCM_NFALSEP (scm_procedure_property (proc,
 179                                                 scm_sym_system_module)))
 180           ? SCM_BOOL_T
 181           : SCM_BOOL_F);
 182 }
 183
 184 /*
 185  * C level implementation of the standard eval closure
 186  *
 187  * This increases loading speed substantially.
 188  * The code will be replaced by the low-level environments in next release.
 189  */
 190
 191 #define OBARRAY(module) (SCM_STRUCT_DATA (module) [0])
 192 #define USES(module) (SCM_STRUCT_DATA (module) [1])
 193 #define BINDER(module) (SCM_STRUCT_DATA (module) [2])
 194
 195 static SCM module_make_local_var_x;
 196
 197 static SCM
 198 module_variable (SCM module, SCM sym)
 199 {
 200   /* 1. Check module obarray */
 201   SCM b = scm_hashq_ref (OBARRAY (module), sym, SCM_UNDEFINED);
 202   if (SCM_VARIABLEP (b))
 203     return b;
 204   {
 205     SCM binder = BINDER (module);
 206     if (SCM_NFALSEP (binder))
 207       /* 2. Custom binder */
 208       {
 209         b = scm_apply (binder,
 210                        SCM_LIST3 (module, sym, SCM_BOOL_F),
 211                        SCM_EOL);
 212         if (SCM_NFALSEP (b))
 213           return b;
 214       }
 215   }
 216   {
 217     /* 3. Search the use list */
 218     SCM uses = USES (module);
 219     while (SCM_CONSP (uses))
 220       {
 221         b = module_variable (SCM_CAR (uses), sym);
 222         if (SCM_NFALSEP (b))
 223           return b;
 224         uses = SCM_CDR (uses);
 225       }
 226     return SCM_BOOL_F;
 227   }
 228 }
 229
 230 static SCM f_eval_closure;
 231
 232 static SCM
 233 eval_closure (SCM cclo, SCM sym, SCM definep)
 234 {
 235   SCM module = SCM_VELTS (cclo) [1];
 236   if (SCM_NFALSEP (definep))
 237     return scm_apply (SCM_CDR (module_make_local_var_x),
 238                       SCM_LIST2 (module, sym),
 239                       SCM_EOL);
 240   else
 241     return module_variable (module, sym);
 242 }
 243
 244 SCM_DEFINE (scm_standard_eval_closure, "standard-eval-closure", 1, 0, 0,
 245             (SCM module),
 246             "")
 247 #define FUNC_NAME s_scm_standard_eval_closure
 248 {
 249   SCM cclo = scm_makcclo (f_eval_closure, SCM_MAKINUM (2));
 250   SCM_VELTS (cclo) [1] = module;
 251   return cclo;
 252 }
 253 #undef FUNC_NAME
 254
 255 void
 256 scm_init_modules ()
 257 {
 258 #include "libguile/modules.x"
 259   root_module_closure = scm_sysintern ("root-module-closure", SCM_UNDEFINED);
 260   scm_module_closure = scm_sysintern ("scm-module-closure", SCM_UNDEFINED);
 261   module_make_local_var_x = scm_sysintern ("module-make-local-var!",
 262                                            SCM_UNDEFINED);
 263   f_eval_closure = scm_make_subr_opt ("eval-closure",
 264                                       scm_tc7_subr_3,
 265                                       eval_closure,
 266                                       0);
 267 }
 268
 269 void
 270 scm_post_boot_init_modules ()
 271 {
 272   the_root_module = scm_intern0 ("the-root-module");
 273   the_module = scm_intern0 ("the-module");
 274   set_current_module = scm_intern0 ("set-current-module");
 275   module_prefix = scm_permanent_object (SCM_LIST2 (scm_sym_app,
 276                                                    scm_sym_modules));
 277   make_modules_in = scm_intern0 ("make-modules-in");
 278   beautify_user_module_x = scm_intern0 ("beautify-user-module!");
 279   module_eval_closure = scm_intern0 ("module-eval-closure");
 280   resolve_module = scm_intern0 ("resolve-module");
 281   try_module_autoload = scm_intern0 ("try-module-autoload");
 282 }
 283
 284 /*
 285   Local Variables:
 286   c-file-style: "gnu"
 287   End:
 288 */