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