libguile/continuations.h

   1 /* classes: h_files */
   2
   3 #ifndef CONTINUATIONSH
   4 #define CONTINUATIONSH
   5 /*      Copyright (C) 1995,1996, 2000 Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this software; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307 USA
  21  *
  22  * As a special exception, the Free Software Foundation gives permission
  23  * for additional uses of the text contained in its release of GUILE.
  24  *
  25  * The exception is that, if you link the GUILE library with other files
  26  * to produce an executable, this does not by itself cause the
  27  * resulting executable to be covered by the GNU General Public License.
  28  * Your use of that executable is in no way restricted on account of
  29  * linking the GUILE library code into it.
  30  *
  31  * This exception does not however invalidate any other reasons why
  32  * the executable file might be covered by the GNU General Public License.
  33  *
  34  * This exception applies only to the code released by the
  35  * Free Software Foundation under the name GUILE.  If you copy
  36  * code from other Free Software Foundation releases into a copy of
  37  * GUILE, as the General Public License permits, the exception does
  38  * not apply to the code that you add in this way.  To avoid misleading
  39  * anyone as to the status of such modified files, you must delete
  40  * this exception notice from them.
  41  *
  42  * If you write modifications of your own for GUILE, it is your choice
  43  * whether to permit this exception to apply to your modifications.
  44  * If you do not wish that, delete this exception notice.  */
  45 \f
  46 #include "libguile/__scm.h"
  47
  48 \f
  49
  50 /* a continuation SCM is a non-immediate pointing to a heap cell with:
  51    word 0: bits 0-15: unused.
  52            bits 16-31: smob type tag: scm_tc16_continuation.
  53    word 1: malloc block containing an scm_contregs structure with a
  54            tail array of SCM_STACKITEM.  the size of the array is stored
  55            in the num_stack_items field of the structure.
  56 */
  57
  58 extern scm_bits_t scm_tc16_continuation;
  59
  60 typedef struct
  61 {
  62   SCM throw_value;
  63   jmp_buf jmpbuf;
  64   SCM dynenv;
  65   SCM_STACKITEM *base;      /* base of the live stack, before it was saved.  */
  66   scm_sizet num_stack_items; /* size of the saved stack.  */
  67   unsigned long seq;         /* dynamic root identifier.  */
  68
  69 #ifdef DEBUG_EXTENSIONS
  70   /* the most recently created debug frame on the live stack, before
  71      it was saved.  */
  72   struct scm_debug_frame *dframe;
  73 #endif
  74   SCM_STACKITEM stack[1];    /* copied stack of size num_stack_items.  */
  75 } scm_contregs;
  76
  77 #define SCM_CONTINUATIONP(x)    SCM_TYP16_PREDICATE (scm_tc16_continuation, x)
  78
  79 #define SCM_CONTREGS(x)         ((scm_contregs *) SCM_CELL_WORD_1 (x))
  80
  81 #define SCM_CONTINUATION_LENGTH(x) (SCM_CONTREGS (x)->num_stack_items)
  82 #define SCM_SET_CONTINUATION_LENGTH(x,n)\
  83    (SCM_CONTREGS (x)->num_stack_items = (n))
  84 #define SCM_JMPBUF(x)           ((SCM_CONTREGS (x))->jmpbuf)
  85 #define SCM_DYNENV(x)           ((SCM_CONTREGS (x))->dynenv)
  86 #define SCM_THROW_VALUE(x)      ((SCM_CONTREGS (x))->throw_value)
  87 #define SCM_BASE(x)             ((SCM_CONTREGS (x))->base)
  88 #define SCM_SEQ(x)              ((SCM_CONTREGS (x))->seq)
  89 #define SCM_DFRAME(x)           ((SCM_CONTREGS (x))->dframe)
  90
  91 \f
  92
  93 extern SCM scm_make_continuation (int *first);
  94 extern void scm_init_continuations (void);
  95
  96 \f
  97
  98 #if (SCM_DEBUG_DEPRECATED == 0)
  99
 100 #define SCM_SETJMPBUF(x, r) (SCM_SET_CONTREGS ((x), (r)))
 101
 102 #endif  /* SCM_DEBUG_DEPRECATED == 0 */
 103
 104 #endif  /* CONTINUATIONSH */
 105
 106 /*
 107   Local Variables:
 108   c-file-style: "gnu"
 109   End:
 110 */