libguile/evalext.c

   1 /*      Copyright (C) 1998, 1999 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 "_scm.h"
  48 #include "eval.h"
  49 #include "macros.h"
  50 #include "modules.h"
  51 #include "root.h"
  52
  53 #include "validate.h"
  54 #include "evalext.h"
  55
  56 SCM_SYMBOL (scm_sym_setter, "setter");
  57
  58 SCM
  59 scm_m_generalized_set_x (SCM xorig, SCM env)
  60 {
  61   SCM x = SCM_CDR (xorig);
  62   SCM_ASSYNT (2 == scm_ilength (x), xorig, scm_s_expression, scm_s_set_x);
  63   if (SCM_SYMBOLP (SCM_CAR (x)))
  64     return scm_cons (SCM_IM_SET_X, x);
  65   else if (SCM_CONSP (SCM_CAR (x)))
  66     return scm_cons (SCM_LIST2 (scm_sym_setter, SCM_CAAR (x)),
  67                      scm_append (SCM_LIST2 (SCM_CDAR (x), SCM_CDR (x))));
  68   return scm_wta (xorig, scm_s_variable, scm_s_set_x);
  69 }
  70
  71 SCM_DEFINE (scm_definedp, "defined?", 1, 1, 0,
  72             (SCM sym, SCM env),
  73             "Return @code{#t} if @var{sym} is defined in the top-level environment.")
  74 #define FUNC_NAME s_scm_definedp
  75 {
  76   SCM vcell;
  77
  78   SCM_VALIDATE_SYMBOL (1,sym);
  79
  80   if (SCM_UNBNDP (env))
  81     vcell = scm_sym2vcell(sym,
  82                           SCM_CDR (scm_top_level_lookup_closure_var),
  83                           SCM_BOOL_F);
  84   else
  85     {
  86       SCM frames = env;
  87       register SCM b;
  88       for (; SCM_NIMP (frames); frames = SCM_CDR (frames))
  89         {
  90           SCM_ASSERT (SCM_CONSP (frames), env, SCM_ARG2, FUNC_NAME);
  91           b = SCM_CAR (frames);
  92           if (SCM_NFALSEP (scm_procedure_p (b)))
  93             break;
  94           SCM_ASSERT (SCM_CONSP (b), env, SCM_ARG2, FUNC_NAME);
  95           for (b = SCM_CAR (b); SCM_NIMP (b); b = SCM_CDR (b))
  96             {
  97               if (SCM_NCONSP (b))
  98                 {
  99                   if (b == sym)
 100                     return SCM_BOOL_T;
 101                   else
 102                     break;
 103                 }
 104               if (SCM_CAR (b) == sym)
 105                 return SCM_BOOL_T;
 106             }
 107         }
 108     vcell = scm_sym2vcell (sym,
 109                            SCM_NIMP (frames) ? SCM_CAR (frames) : SCM_BOOL_F,
 110                            SCM_BOOL_F);
 111     }
 112
 113   return (vcell == SCM_BOOL_F || SCM_UNBNDP (SCM_CDR (vcell))
 114           ? SCM_BOOL_F
 115           : SCM_BOOL_T);
 116 }
 117 #undef FUNC_NAME
 118
 119
 120 SCM_SYNTAX (s_undefine, "undefine", scm_makacro, scm_m_undefine);
 121
 122 SCM
 123 scm_m_undefine (SCM x, SCM env)
 124 {
 125   SCM arg1 = x;
 126   x = SCM_CDR (x);
 127   SCM_ASSYNT (SCM_TOP_LEVEL (env), arg1, "bad placement ", s_undefine);
 128   SCM_ASSYNT (SCM_CONSP (x) && SCM_CDR (x) == SCM_EOL,
 129               arg1, scm_s_expression, s_undefine);
 130   x = SCM_CAR (x);
 131   SCM_ASSYNT (SCM_SYMBOLP (x), arg1, scm_s_variable, s_undefine);
 132   arg1 = scm_sym2vcell (x, scm_env_top_level (env), SCM_BOOL_F);
 133   SCM_ASSYNT (SCM_NFALSEP (arg1) && !SCM_UNBNDP (SCM_CDR (arg1)),
 134               x, "variable already unbound ", s_undefine);
 135 #if 0
 136 #ifndef SCM_RECKLESS
 137   if (SCM_NIMP (SCM_CDR (arg1)) && ((SCM) SCM_SNAME (SCM_CDR (arg1)) == x))
 138     scm_warn ("undefining built-in ", SCM_CHARS (x));
 139   else
 140 #endif
 141     if (5 <= scm_verbose && SCM_UNDEFINED != SCM_CDR (arg1))
 142       scm_warn ("redefining ", SCM_CHARS (x));
 143 #endif
 144   SCM_SETCDR (arg1, SCM_UNDEFINED);
 145 #ifdef SICP
 146   return SCM_CAR (arg1);
 147 #else
 148   return SCM_UNSPECIFIED;
 149 #endif
 150 }
 151
 152 /* This name is obsolete.  Will be removed in 1.5.  */
 153 SCM_REGISTER_PROC (s_serial_map, "serial-map", 2, 0, 1, scm_map);
 154
 155 SCM_REGISTER_PROC (s_map_in_order, "map-in-order", 2, 0, 1, scm_map);
 156
 157 void
 158 scm_init_evalext ()
 159 {
 160   scm_make_synt (scm_s_set_x, scm_makmmacro, scm_m_generalized_set_x);
 161 #include "evalext.x"
 162 }
 163
 164 /*
 165   Local Variables:
 166   c-file-style: "gnu"
 167   End:
 168 */