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cd038da546
* libguile/Makefile.am: * libguile/init.c: * libguile/lang.c: * libguile/lang.h: Remove lang.c and lang.h. * libguile/pairs.h (SCM_NIL_P, SCM_NULL_OR_NIL_P): Moved here. * module/ice-9/deprecated.scm (%nil): %nil definition moved here. * libguile/alist.c: * libguile/async.c: * libguile/backtrace.c: * libguile/boolean.c: * libguile/dynl.c: * libguile/eval.c: * libguile/filesys.c: * libguile/fluids.c: * libguile/list.c: * libguile/load.c: * libguile/options.c: * libguile/posix.c: * libguile/print.c: * libguile/promises.c: * libguile/sort.c: * libguile/throw.c: * libguile/trees.c: * libguile/vectors.c: * libguile/vm.c: * libguile/weaks.c: * srfi/srfi-1.c: <libguile/lang.h> references removed.
149 lines
4 KiB
C
149 lines
4 KiB
C
/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010
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* Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 3 of
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* the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <alloca.h>
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#include "libguile/__scm.h"
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#include "libguile/_scm.h"
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#include "libguile/alist.h"
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#include "libguile/async.h"
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#include "libguile/continuations.h"
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#include "libguile/debug.h"
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#include "libguile/deprecation.h"
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#include "libguile/dynwind.h"
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#include "libguile/eq.h"
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#include "libguile/eval.h"
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#include "libguile/feature.h"
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#include "libguile/fluids.h"
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#include "libguile/goops.h"
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#include "libguile/hash.h"
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#include "libguile/hashtab.h"
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#include "libguile/list.h"
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#include "libguile/macros.h"
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#include "libguile/memoize.h"
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#include "libguile/modules.h"
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#include "libguile/ports.h"
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#include "libguile/print.h"
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#include "libguile/procprop.h"
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#include "libguile/programs.h"
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#include "libguile/root.h"
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#include "libguile/smob.h"
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#include "libguile/srcprop.h"
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#include "libguile/stackchk.h"
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#include "libguile/strings.h"
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#include "libguile/threads.h"
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#include "libguile/throw.h"
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#include "libguile/validate.h"
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#include "libguile/values.h"
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#include "libguile/promises.h"
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scm_t_bits scm_tc16_promise;
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SCM_DEFINE (scm_make_promise, "make-promise", 1, 0, 0,
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(SCM thunk),
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"Create a new promise object.\n\n"
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"@code{make-promise} is a procedural form of @code{delay}.\n"
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"These two expressions are equivalent:\n"
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"@lisp\n"
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"(delay @var{exp})\n"
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"(make-promise (lambda () @var{exp}))\n"
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"@end lisp\n")
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#define FUNC_NAME s_scm_make_promise
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{
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SCM_VALIDATE_THUNK (1, thunk);
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SCM_RETURN_NEWSMOB2 (scm_tc16_promise,
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SCM_UNPACK (thunk),
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scm_make_recursive_mutex ());
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}
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#undef FUNC_NAME
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static int
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promise_print (SCM exp, SCM port, scm_print_state *pstate)
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{
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int writingp = SCM_WRITINGP (pstate);
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scm_puts ("#<promise ", port);
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SCM_SET_WRITINGP (pstate, 1);
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scm_iprin1 (SCM_PROMISE_DATA (exp), port, pstate);
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SCM_SET_WRITINGP (pstate, writingp);
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scm_putc ('>', port);
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return !0;
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}
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SCM_DEFINE (scm_force, "force", 1, 0, 0,
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(SCM promise),
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"If the promise @var{x} has not been computed yet, compute and\n"
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"return @var{x}, otherwise just return the previously computed\n"
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"value.")
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#define FUNC_NAME s_scm_force
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{
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SCM_VALIDATE_SMOB (1, promise, promise);
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scm_lock_mutex (SCM_PROMISE_MUTEX (promise));
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if (!SCM_PROMISE_COMPUTED_P (promise))
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{
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SCM ans = scm_call_0 (SCM_PROMISE_DATA (promise));
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if (!SCM_PROMISE_COMPUTED_P (promise))
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{
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SCM_SET_PROMISE_DATA (promise, ans);
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SCM_SET_PROMISE_COMPUTED (promise);
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}
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}
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scm_unlock_mutex (SCM_PROMISE_MUTEX (promise));
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return SCM_PROMISE_DATA (promise);
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_promise_p, "promise?", 1, 0, 0,
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(SCM obj),
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"Return true if @var{obj} is a promise, i.e. a delayed computation\n"
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"(@pxref{Delayed evaluation,,,r5rs.info,The Revised^5 Report on Scheme}).")
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#define FUNC_NAME s_scm_promise_p
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{
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return scm_from_bool (SCM_TYP16_PREDICATE (scm_tc16_promise, obj));
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}
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#undef FUNC_NAME
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void
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scm_init_promises ()
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{
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scm_tc16_promise = scm_make_smob_type ("promise", 0);
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scm_set_smob_print (scm_tc16_promise, promise_print);
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#include "libguile/promises.x"
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scm_add_feature ("delay");
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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