libguile/lang.c

   1 /*      Copyright (C) 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
  49 #include "eval.h"
  50 #include "macros.h"
  51 #include "root.h"
  52
  53 #include "validate.h"
  54 #include "lang.h"
  55
  56 \f
  57
  58 /* {Multi-language support}
  59  */
  60
  61 /* Representation of pairs:
  62  *
  63  * Since we're going to share data with Scheme, we use EOL instead of nil
  64  * in all data structures.
  65  */
  66
  67 SCM_DEFINE (scm_nil_cons, "nil-cons", 2, 0, 0,
  68             (SCM x, SCM y),
  69 "")
  70 #define FUNC_NAME s_scm_nil_cons
  71 {
  72   register SCM z;
  73   SCM_NEWCELL (z);
  74   SCM_SETCAR (z, x);
  75   SCM_SETCDR (z, SCM_NIL2EOL (y, y));
  76   return z;
  77 }
  78 #undef FUNC_NAME
  79
  80
  81 SCM_DEFINE (scm_nil_car, "nil-car", 1, 0, 0,
  82             (SCM x),
  83 "")
  84 #define FUNC_NAME s_scm_nil_car
  85 {
  86   if (SCM_NILP (x))
  87     return scm_lisp_nil;
  88   SCM_VALIDATE_CONS (1,x);
  89   return SCM_CAR (x);
  90 }
  91 #undef FUNC_NAME
  92
  93 SCM_DEFINE (scm_nil_cdr, "nil-cdr", 1, 0, 0,
  94             (SCM x),
  95 "")
  96 #define FUNC_NAME s_scm_nil_cdr
  97 {
  98   if (SCM_NILP (x))
  99     return scm_lisp_nil;
 100   SCM_VALIDATE_CONS (1,x);
 101   return SCM_EOL2NIL (SCM_CDR (x), x);
 102 }
 103 #undef FUNC_NAME
 104
 105 /* GJB:FIXME:: why does this return scm_lisp_nil instead of SCM_BOOL_F?
 106    Could use SCM_BOOL, below, otherwise */
 107 SCM_DEFINE (scm_null, "null", 1, 0, 0,
 108             (SCM x),
 109 "")
 110 #define FUNC_NAME s_scm_null
 111 {
 112   return (SCM_NILP (x) || SCM_NULLP (x) || SCM_FALSEP (x)) ? scm_lisp_t : scm_lisp_nil;
 113 }
 114 #undef FUNC_NAME
 115
 116 SCM
 117 scm_m_while (SCM exp, SCM env)
 118 {
 119   register SCM x = exp = SCM_CDR (exp);
 120   SCM z = scm_eval_car (x, env);
 121   while (!SCM_NILP (z) && SCM_NFALSEP (z))
 122     {
 123       while (SCM_NNULLP (x = SCM_CDR (x)))
 124         {
 125           if (SCM_NIMP (SCM_CAR (x)))
 126             (*scm_ceval_ptr) (SCM_CAR (x), env);
 127         }
 128       z = scm_eval_car (x = exp, env);
 129     }
 130   return scm_lisp_nil;
 131 }
 132
 133 /* GJB:FIXME:: why does this return scm_lisp_nil instead of SCM_BOOL_F?
 134    Could use SCM_BOOL, below, otherwise */
 135 SCM_DEFINE1 (scm_nil_eq, "nil-eq", scm_tc7_rpsubr,
 136              (SCM x, SCM y),
 137 "")
 138 #define FUNC_NAME s_scm_nil_eq
 139 {
 140   return (((x==y)
 141            || (SCM_NILP (x) && (SCM_NULLP (y) || SCM_FALSEP (y)))
 142            || (SCM_NILP (y) && (SCM_NULLP (x) || SCM_FALSEP (x))))
 143           ? scm_lisp_t
 144           : scm_lisp_nil);
 145 }
 146 #undef FUNC_NAME
 147
 148 \f
 149
 150 void
 151 scm_init_lang ()
 152 {
 153 #include "lang.x"
 154   scm_make_synt ("nil-while", scm_makacro, scm_m_while);
 155 }
 156
 157 /*
 158   Local Variables:
 159   c-file-style: "gnu"
 160   End:
 161 */