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3cf4ca187c
The goal was that, as part of a print operation, all nested prints of
contained data would be able to use the same parameters (e.g. write or
not), and also detect cycles, highlight objects, etc. The mechanism was
a heap-allocated data structure. However, given that:
1. Nobody accessed print states from Scheme
2. `write` and `display` should move to Scheme anyway, in order to be
suspendable
3. The "fancyp" and "highlight" options were unused
4. A simple stack-allocated data structure with a per-thread key could
do the trick just as well, without needing the weird freelist
structure
5. Ports-with-print-states were a source of bugs
In the end we switch print states to be something completely internal to
print.c. There are no more SCM print-state objects, and no more
ports-with-print-state.
* libguile/print.h: Remove print state from API.
* libguile/print.c (struct scm_print_state): Move definition here.
(scm_print_opts): Remove "highlight-prefix" and "highlight-suffix"
options, as they were not used.
(ENTER_NESTED_DATA): Remove "fancyp" case.
(init_print_state_key, get_print_state, push_print_state)
(maybe_push_print_state, pop_print_state): New facility to manage stack
of active print states.
(scm_iprin1, print_vector): No more fancyp.
(iprin1): Access "writingp" member directly. Don't make ports with
print states.
(scm_prin1): Manage print state stack.
(scm_iprlist): No more fancyp.
(scm_valid_oport_value_p): Remove; valid outports are SCM_OPOUTPORTP.
* libguile/backtrace.c:
* libguile/filesys.c:
* libguile/fports.c:
* libguile/goops.c:
* libguile/ioext.c:
* libguile/ports.c:
* libguile/posix.c:
* libguile/promises.c:
* libguile/socket.c:
* libguile/struct.c: Remove cases that dealt with
ports-with-print-states.
* libguile/private-options.h: Remove highlight options.
* module/ice-9/ports.scm (inherit-print-state): Deprecate.
* libguile/deprecated.c:
* libguile/deprecated.h: Add deprecation shims for print states, as far
as that is possible.
135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
/* Copyright 1995-2011,2018,2025
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Free Software Foundation, Inc.
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This file is part of Guile.
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Guile is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Guile is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with Guile. If not, see
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<https://www.gnu.org/licenses/>. */
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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 "alist.h"
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#include "async.h"
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#include "continuations.h"
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#include "debug.h"
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#include "deprecation.h"
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#include "dynwind.h"
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#include "eq.h"
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#include "eval.h"
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#include "feature.h"
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#include "fluids.h"
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#include "goops.h"
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#include "gsubr.h"
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#include "hash.h"
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#include "hashtab.h"
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#include "list.h"
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#include "macros.h"
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#include "memoize.h"
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#include "modules.h"
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#include "ports.h"
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#include "print.h"
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#include "procprop.h"
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#include "procs.h"
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#include "programs.h"
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#include "smob.h"
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#include "stackchk.h"
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#include "strings.h"
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#include "threads.h"
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#include "throw.h"
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#include "values.h"
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#include "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_UNPACK (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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scm_puts ("#<promise ", port);
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scm_write (SCM_PROMISE_DATA (exp), port);
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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 @var{promise} has not been computed yet, compute and\n"
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"return @var{promise}, 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 "promises.x"
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scm_add_feature ("delay");
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}
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