libguile/evalext.c

   1 /*      Copyright (C) 1998 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 #include "_scm.h"
  44 #include "eval.h"
  45 #include "macros.h"
  46
  47 #include "evalext.h"
  48
  49 SCM_PROC (s_definedp, "defined?", 1, 0, 0, scm_definedp);
  50
  51 SCM
  52 scm_definedp (sym)
  53      SCM sym;
  54 {
  55   SCM vcell;
  56
  57   if (SCM_ISYMP (sym))
  58     return SCM_BOOL_T;
  59
  60   SCM_ASSERT (SCM_NIMP (sym) && SCM_SYMBOLP (sym), sym, SCM_ARG1, s_definedp);
  61
  62   vcell = scm_sym2vcell(sym,
  63                         SCM_CDR (scm_top_level_lookup_closure_var),
  64                         SCM_BOOL_F);
  65   return (vcell == SCM_BOOL_F || SCM_UNBNDP(SCM_CDR(vcell))) ?
  66       SCM_BOOL_F : SCM_BOOL_T;
  67 }
  68
  69 static char s_undefine[] = "undefine";
  70
  71 SCM
  72 scm_m_undefine (x, env)
  73      SCM x, env;
  74 {
  75   SCM arg1 = x;
  76   x = SCM_CDR (x);
  77   SCM_ASSYNT (SCM_TOP_LEVEL (env), arg1, "bad placement ", s_undefine);
  78   SCM_ASSYNT (SCM_NIMP (x) && SCM_CONSP (x) && SCM_CDR (x) == SCM_EOL,
  79               arg1, scm_s_expression, s_undefine);
  80   x = SCM_CAR (x);
  81   SCM_ASSYNT (SCM_NIMP (x) && SCM_SYMBOLP (x), arg1, scm_s_variable, s_undefine);
  82   arg1 = scm_sym2vcell (x, scm_env_top_level (env), SCM_BOOL_F);
  83   SCM_ASSYNT (SCM_NFALSEP (arg1) && !SCM_UNBNDP (SCM_CDR (arg1)),
  84               x, "variable already unbound ", s_undefine);
  85 #if 0
  86 #ifndef SCM_RECKLESS
  87   if (SCM_NIMP (SCM_CDR (arg1)) && ((SCM) SCM_SNAME (SCM_CDR (arg1)) == x))
  88     scm_warn ("undefining built-in ", SCM_CHARS (x));
  89   else
  90 #endif
  91     if (5 <= scm_verbose && SCM_UNDEFINED != SCM_CDR (arg1))
  92       scm_warn ("redefining ", SCM_CHARS (x));
  93 #endif
  94   SCM_SETCDR (arg1, SCM_UNDEFINED);
  95 #ifdef SICP
  96   return SCM_CAR (arg1);
  97 #else
  98   return SCM_UNSPECIFIED;
  99 #endif
 100 }
 101
 102
 103 SCM_PROC (s_serial_map, "serial-map", 2, 0, 1, scm_map);
 104
 105 void
 106 scm_init_evalext ()
 107 {
 108   scm_make_synt (s_undefine, scm_makacro, scm_m_undefine);
 109 #include "evalext.x"
 110 }