libguile/values.c

   1 /* Copyright (C) 2000, 2001 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 #include "libguile/_scm.h"
  43 #include "libguile/eval.h"
  44 #include "libguile/feature.h"
  45 #include "libguile/gc.h"
  46 #include "libguile/numbers.h"
  47 #include "libguile/ports.h"
  48 #include "libguile/root.h"
  49 #include "libguile/strings.h"
  50 #include "libguile/struct.h"
  51 #include "libguile/validate.h"
  52
  53 #include "libguile/values.h"
  54
  55 SCM scm_values_vtable;
  56
  57 static SCM
  58 print_values (SCM obj, SCM pwps)
  59 {
  60   SCM values = scm_struct_ref (obj, SCM_INUM0);
  61   SCM port = SCM_PORT_WITH_PS_PORT (pwps);
  62   scm_print_state *ps = SCM_PRINT_STATE (SCM_PORT_WITH_PS_PS (pwps));
  63
  64   scm_puts ("#<values ", port);
  65   scm_iprin1 (values, port, ps);
  66   scm_puts (">", port);
  67
  68   return SCM_UNSPECIFIED;
  69 }
  70
  71 SCM_DEFINE (scm_values, "values", 0, 0, 1,
  72             (SCM args),
  73             "Delivers all of its arguments to its continuation.  Except for\n"
  74             "continuations created by the @code{call-with-values} procedure,\n"
  75             "all continuations take exactly one value.  The effect of\n"
  76             "passing no value or more than one value to continuations that\n"
  77             "were not created by @code{call-with-values} is unspecified.")
  78 #define FUNC_NAME s_scm_values
  79 {
  80   long n;
  81   SCM result;
  82
  83   SCM_VALIDATE_LIST_COPYLEN (1, args, n);
  84   if (n == 1)
  85     result = SCM_CAR (args);
  86   else
  87     {
  88       result = scm_make_struct (scm_values_vtable, SCM_INUM0,
  89                                 scm_cons (args, SCM_EOL));
  90     }
  91
  92   return result;
  93 }
  94 #undef FUNC_NAME
  95
  96 void
  97 scm_init_values (void)
  98 {
  99   SCM print = scm_c_define_subr ("%print-values", scm_tc7_subr_2,
 100                                  print_values);
 101
 102   scm_values_vtable
 103     = scm_permanent_object (scm_make_vtable_vtable (scm_makfrom0str ("pr"),
 104                                                     SCM_INUM0, SCM_EOL));
 105   SCM_SET_STRUCT_PRINTER (scm_values_vtable, print);
 106
 107   scm_add_feature ("values");
 108
 109 #ifndef SCM_MAGIC_SNARFER
 110 #include "libguile/values.x"
 111 #endif
 112 }
 113
 114 /*
 115   Local Variables:
 116   c-file-style: "gnu"
 117   End:
 118 */