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/* Copyright (C) 1995,1996 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* As a special exception, the Free Software Foundation gives permission
* for additional uses of the text contained in its release of GUILE.
*
* The exception is that, if you link the GUILE library with other files
* to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the GUILE library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the
* Free Software Foundation under the name GUILE. If you copy
* code from other Free Software Foundation releases into a copy of
* GUILE, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for GUILE, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice.
*/
#include <stdio.h>
#include "_scm.h"
#include "genio.h"
#include "smob.h"
#include "alist.h"
#include "eval.h"
#include "dynwind.h"
#ifdef DEBUG_EXTENSIONS
#include "debug.h"
#endif
#include "continuations.h"
#include "throw.h"
/* {Catch and Throw}
*/
static int scm_tc16_jmpbuffer;
SCM scm_bad_throw_vcell;
#define SCM_JMPBUFP(O) (SCM_TYP16(O) == scm_tc16_jmpbuffer)
#define JBACTIVE(O) (SCM_CAR (O) & (1L << 16L))
#define ACTIVATEJB(O) (SCM_CAR (O) |= (1L << 16L))
#define DEACTIVATEJB(O) (SCM_CAR (O) &= ~(1L << 16L))
#ifndef DEBUG_EXTENSIONS
#define JBJMPBUF(O) ((jmp_buf*)SCM_CDR (O) )
#define SETJBJMPBUF SCM_SETCDR
#else
#define JBSCM_DFRAME(O) ((scm_debug_frame*)SCM_CAR (SCM_CDR (O)) )
#define JBJMPBUF(O) ((jmp_buf*)SCM_CDR (SCM_CDR (O)) )
#define SETJBSCM_DFRAME(O,X) SCM_CAR(SCM_CDR (O)) = (SCM)(X)
#define SETJBJMPBUF(O,X) SCM_SETCDR(SCM_CDR (O), X)
#ifdef __STDC__
static scm_sizet
freejb (SCM jbsmob)
#else
static scm_sizet
freejb (jbsmob)
SCM jbsmob;
#endif
{
scm_must_free ((char *) SCM_CDR (jbsmob));
return sizeof (scm_cell);
}
#endif
#ifdef __STDC__
static int
printjb (SCM exp, SCM port, int writing)
#else
static int
printjb (exp, port, writing)
SCM exp;
SCM port;
int writing;
#endif
{
scm_gen_puts (scm_regular_string, "#<jmpbuffer ", port);
scm_gen_puts (scm_regular_string, JBACTIVE(exp) ? "(active) " : "(inactive) ", port);
scm_intprint((SCM) JBJMPBUF(exp), 16, port);
scm_gen_putc ('>', port);
return 1 ;
}
static scm_smobfuns jbsmob = {
scm_mark0,
#ifdef DEBUG_EXTENSIONS
freejb,
#else
scm_free0,
#endif
printjb,
0
};
#ifdef __STDC__
static SCM
make_jmpbuf (void)
#else
static SCM
make_jmpbuf ()
#endif
{
SCM answer;
SCM_NEWCELL (answer);
SCM_DEFER_INTS;
{
#ifdef DEBUG_EXTENSIONS
char *mem = scm_must_malloc (sizeof (scm_cell), "jb");
SCM_SETCDR (answer, (SCM) mem);
#endif
SCM_CAR(answer) = scm_tc16_jmpbuffer;
SETJBJMPBUF(answer, (jmp_buf *)0);
DEACTIVATEJB(answer);
}
SCM_ALLOW_INTS;
return answer;
}
struct jmp_buf_and_retval /* use only on the stack, in scm_catch */
{
jmp_buf buf; /* must be first */
SCM throw_tag;
SCM retval;
};
SCM_PROC(s_catch, "catch", 3, 0, 0, scm_catch);
#ifdef __STDC__
SCM
scm_catch (SCM tag, SCM thunk, SCM handler)
#else
SCM
scm_catch (tag, thunk, handler)
SCM tag;
SCM thunk;
SCM handler;
#endif
{
struct jmp_buf_and_retval jbr;
SCM jmpbuf;
SCM answer;
SCM_ASSERT ((tag == SCM_BOOL_F) || (SCM_NIMP(tag) && SCM_SYMBOLP(tag)) || (tag == SCM_BOOL_T),
tag, SCM_ARG1, s_catch);
jmpbuf = make_jmpbuf ();
answer = SCM_EOL;
scm_dynwinds = scm_acons (tag, jmpbuf, scm_dynwinds);
SETJBJMPBUF(jmpbuf, &jbr.buf);
#ifdef DEBUG_EXTENSIONS
SETJBSCM_DFRAME(jmpbuf, last_debug_info_frame);
#endif
if (setjmp (jbr.buf))
{
SCM throw_tag;
SCM throw_args;
SCM_DEFER_INTS;
DEACTIVATEJB (jmpbuf);
scm_dynwinds = SCM_CDR (scm_dynwinds);
SCM_ALLOW_INTS;
throw_args = jbr.retval;
throw_tag = jbr.throw_tag;
jbr.throw_tag = SCM_EOL;
jbr.retval = SCM_EOL;
answer = scm_apply (handler, scm_cons (throw_tag, throw_args), SCM_EOL);
}
else
{
ACTIVATEJB (jmpbuf);
answer = scm_apply (thunk,
((tag == SCM_BOOL_F) ? scm_cons (jmpbuf, SCM_EOL) : SCM_EOL),
SCM_EOL);
SCM_DEFER_INTS;
DEACTIVATEJB (jmpbuf);
scm_dynwinds = SCM_CDR (scm_dynwinds);
SCM_ALLOW_INTS;
}
return answer;
}
static char s_throw[];
#ifdef __STDC__
SCM
scm_ithrow (SCM key, SCM args, int noreturn)
#else
SCM
scm_ithrow (key, args, noreturn)
SCM key;
SCM args;
int noreturn;
#endif
{
SCM jmpbuf;
SCM wind_goal;
if (SCM_NIMP (key) && SCM_JMPBUFP (key))
{
jmpbuf = key;
if (noreturn)
{
SCM_ASSERT (JBACTIVE (jmpbuf), jmpbuf,
"throw to dynamically inactive catch",
s_throw);
}
else if (!JBACTIVE (jmpbuf))
return SCM_UNSPECIFIED;
}
else
{
SCM dynpair;
SCM hook;
if (noreturn)
{
SCM_ASSERT (SCM_NIMP (key) && SCM_SYMBOLP (key), key, SCM_ARG1, s_throw);
}
else if (!(SCM_NIMP (key) && SCM_SYMBOLP (key)))
return SCM_UNSPECIFIED;
dynpair = scm_sloppy_assq (key, scm_dynwinds);
if (dynpair == SCM_BOOL_F)
dynpair = scm_sloppy_assq (SCM_BOOL_T, scm_dynwinds);
hook = SCM_CDR (scm_bad_throw_vcell);
if ((dynpair == SCM_BOOL_F)
&& (SCM_BOOL_T == scm_procedure_p (hook)))
{
SCM answer;
answer = scm_apply (hook, scm_cons (key, args), SCM_EOL);
}
if (dynpair != SCM_BOOL_F)
jmpbuf = SCM_CDR (dynpair);
else
{
if (!noreturn)
return SCM_UNSPECIFIED;
else
{
scm_exitval = scm_cons (key, args);
scm_dowinds (SCM_EOL, scm_ilength (scm_dynwinds));
#ifdef DEBUG_EXTENSIONS
last_debug_info_frame = SCM_DFRAME (scm_rootcont);
#endif
longjmp (SCM_JMPBUF (scm_rootcont), 1);
}
}
}
for (wind_goal = scm_dynwinds;
SCM_CDAR (wind_goal) != jmpbuf;
wind_goal = SCM_CDR (wind_goal))
;
{
struct jmp_buf_and_retval * jbr;
jbr = (struct jmp_buf_and_retval *)JBJMPBUF (jmpbuf);
jbr->throw_tag = key;
jbr->retval = args;
}
scm_dowinds (wind_goal, scm_ilength (scm_dynwinds) - scm_ilength (wind_goal));
#ifdef DEBUG_EXTENSIONS
last_debug_info_frame = JBSCM_DFRAME (jmpbuf);
#endif
longjmp (*JBJMPBUF (jmpbuf), 1);
}
SCM_PROC(s_throw, "throw", 1, 0, 1, scm_throw);
#ifdef __STDC__
SCM
scm_throw (SCM key, SCM args)
#else
SCM
scm_throw (key, args)
SCM key;
SCM args;
#endif
{
scm_ithrow (key, args, 1);
return SCM_BOOL_F; /* never really returns */
}
#ifdef __STDC__
void
scm_init_throw (void)
#else
void
scm_init_throw ()
#endif
{
scm_tc16_jmpbuffer = scm_newsmob (&jbsmob);
scm_bad_throw_vcell = scm_sysintern ("%%bad-throw", SCM_BOOL_F);
#include "throw.x"
}
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