mirror of
https://git.savannah.gnu.org/git/guile.git
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7af531508c
Conflicts: libguile/Makefile.am libguile/bytevectors.c libguile/gc-card.c libguile/gc-mark.c libguile/programs.c libguile/srcprop.c libguile/srfi-14.c libguile/symbols.c libguile/threads.c libguile/unif.c libguile/vm.c
463 lines
13 KiB
C
463 lines
13 KiB
C
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003, 2004, 2006, 2009 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 "libguile/_scm.h"
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#include "libguile/chars.h"
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#include "libguile/eval.h"
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#include "libguile/hash.h"
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#include "libguile/smob.h"
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#include "libguile/variable.h"
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#include "libguile/alist.h"
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#include "libguile/fluids.h"
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#include "libguile/strings.h"
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#include "libguile/vectors.h"
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#include "libguile/hashtab.h"
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#include "libguile/weaks.h"
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#include "libguile/modules.h"
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#include "libguile/read.h"
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#include "libguile/srfi-13.h"
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#include "libguile/validate.h"
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#include "libguile/symbols.h"
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#include "libguile/private-options.h"
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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static SCM symbols;
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#ifdef GUILE_DEBUG
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SCM_DEFINE (scm_sys_symbols, "%symbols", 0, 0, 0,
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(),
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"Return the system symbol obarray.")
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#define FUNC_NAME s_scm_sys_symbols
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{
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return symbols;
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}
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#undef FUNC_NAME
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#endif
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/* {Symbols}
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*/
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/* In order to optimize reading speed, this function breaks part of
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* the hashtable abstraction. The optimizations are:
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*
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* 1. The argument string can be compared directly to symbol objects
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* without first creating an SCM string object. (This would have
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* been necessary if we had used the hashtable API in hashtab.h.)
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*
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* 2. We can use the raw hash value stored in scm_i_symbol_hash (sym)
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* to speed up lookup.
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*
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* Both optimizations might be possible without breaking the
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* abstraction if the API in hashtab.c is improved.
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*/
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unsigned long
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scm_i_hash_symbol (SCM obj, unsigned long n, void *closure)
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{
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return scm_i_symbol_hash (obj) % n;
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}
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static SCM
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lookup_interned_symbol (SCM name, unsigned long raw_hash)
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{
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/* Try to find the symbol in the symbols table */
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SCM result = SCM_BOOL_F;
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SCM bucket, elt, previous_elt;
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size_t len;
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unsigned long hash = raw_hash % SCM_HASHTABLE_N_BUCKETS (symbols);
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len = scm_i_string_length (name);
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bucket = SCM_HASHTABLE_BUCKET (symbols, hash);
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for (elt = bucket, previous_elt = SCM_BOOL_F;
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!scm_is_null (elt);
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previous_elt = elt, elt = SCM_CDR (elt))
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{
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SCM pair, sym;
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pair = SCM_CAR (elt);
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if (!scm_is_pair (pair))
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abort ();
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if (SCM_WEAK_PAIR_CAR_DELETED_P (pair))
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{
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/* PAIR is a weak pair whose key got nullified: remove it from
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BUCKET. */
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/* FIXME: Since this is done lazily, i.e., only when a new symbol
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is to be inserted in a bucket containing deleted symbols, the
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number of items in the hash table may remain erroneous for some
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time, thus precluding proper rehashing. */
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if (previous_elt != SCM_BOOL_F)
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SCM_SETCDR (previous_elt, SCM_CDR (elt));
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else
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bucket = SCM_CDR (elt);
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SCM_HASHTABLE_DECREMENT (symbols);
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continue;
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}
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sym = SCM_CAR (pair);
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if (scm_i_symbol_hash (sym) == raw_hash
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&& scm_i_symbol_length (sym) == len)
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{
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size_t i = len;
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/* Slightly faster path for comparing narrow to narrow. */
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if (scm_i_is_narrow_string (name) && scm_i_is_narrow_symbol (sym))
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{
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const char *chrs = scm_i_symbol_chars (sym);
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const char *str = scm_i_string_chars (name);
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while (i != 0)
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{
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--i;
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if (str[i] != chrs[i])
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goto next_symbol;
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}
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}
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else
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{
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/* Somewhat slower path for comparing narrow to wide or
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wide to wide. */
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while (i != 0)
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{
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--i;
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if (scm_i_string_ref (name, i) != scm_i_symbol_ref (sym, i))
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goto next_symbol;
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}
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}
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/* We found it. */
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result = sym;
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break;
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}
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next_symbol:
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;
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}
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if (SCM_HASHTABLE_N_ITEMS (symbols) < SCM_HASHTABLE_LOWER (symbols))
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/* We removed many symbols in this pass so trigger a rehashing. */
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scm_i_rehash (symbols, scm_i_hash_symbol, 0, "lookup_interned_symbol");
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return result;
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}
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/* Intern SYMBOL, an uninterned symbol. */
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static void
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intern_symbol (SCM symbol)
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{
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SCM slot, cell;
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unsigned long hash;
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hash = scm_i_symbol_hash (symbol) % SCM_HASHTABLE_N_BUCKETS (symbols);
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slot = SCM_HASHTABLE_BUCKET (symbols, hash);
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cell = scm_cons (symbol, SCM_UNDEFINED);
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SCM_SET_HASHTABLE_BUCKET (symbols, hash, scm_cons (cell, slot));
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SCM_HASHTABLE_INCREMENT (symbols);
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if (SCM_HASHTABLE_N_ITEMS (symbols) > SCM_HASHTABLE_UPPER (symbols))
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scm_i_rehash (symbols, scm_i_hash_symbol, 0, "intern_symbol");
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}
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static SCM
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scm_i_str2symbol (SCM str)
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{
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SCM symbol;
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size_t raw_hash = scm_i_string_hash (str);
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symbol = lookup_interned_symbol (str, raw_hash);
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if (scm_is_false (symbol))
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{
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/* The symbol was not found, create it. */
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symbol = scm_i_make_symbol (str, 0, raw_hash,
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scm_cons (SCM_BOOL_F, SCM_EOL));
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intern_symbol (symbol);
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}
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return symbol;
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}
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static SCM
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scm_i_str2uninterned_symbol (SCM str)
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{
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size_t raw_hash = scm_i_string_hash (str);
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return scm_i_make_symbol (str, SCM_I_F_SYMBOL_UNINTERNED,
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raw_hash, scm_cons (SCM_BOOL_F, SCM_EOL));
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}
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SCM_DEFINE (scm_symbol_p, "symbol?", 1, 0, 0,
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(SCM obj),
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"Return @code{#t} if @var{obj} is a symbol, otherwise return\n"
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"@code{#f}.")
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#define FUNC_NAME s_scm_symbol_p
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{
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return scm_from_bool (scm_is_symbol (obj));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_interned_p, "symbol-interned?", 1, 0, 0,
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(SCM symbol),
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"Return @code{#t} if @var{symbol} is interned, otherwise return\n"
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"@code{#f}.")
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#define FUNC_NAME s_scm_symbol_interned_p
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{
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SCM_VALIDATE_SYMBOL (1, symbol);
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return scm_from_bool (scm_i_symbol_is_interned (symbol));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_make_symbol, "make-symbol", 1, 0, 0,
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(SCM name),
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"Return a new uninterned symbol with the name @var{name}. "
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"The returned symbol is guaranteed to be unique and future "
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"calls to @code{string->symbol} will not return it.")
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#define FUNC_NAME s_scm_make_symbol
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{
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SCM_VALIDATE_STRING (1, name);
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return scm_i_str2uninterned_symbol (name);
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_to_string, "symbol->string", 1, 0, 0,
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(SCM s),
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"Return the name of @var{symbol} as a string. If the symbol was\n"
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"part of an object returned as the value of a literal expression\n"
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"(section @pxref{Literal expressions,,,r5rs, The Revised^5\n"
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"Report on Scheme}) or by a call to the @code{read} procedure,\n"
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"and its name contains alphabetic characters, then the string\n"
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"returned will contain characters in the implementation's\n"
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"preferred standard case---some implementations will prefer\n"
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"upper case, others lower case. If the symbol was returned by\n"
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"@code{string->symbol}, the case of characters in the string\n"
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"returned will be the same as the case in the string that was\n"
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"passed to @code{string->symbol}. It is an error to apply\n"
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"mutation procedures like @code{string-set!} to strings returned\n"
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"by this procedure.\n"
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"\n"
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"The following examples assume that the implementation's\n"
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"standard case is lower case:\n"
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"\n"
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"@lisp\n"
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"(symbol->string 'flying-fish) @result{} \"flying-fish\"\n"
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"(symbol->string 'Martin) @result{} \"martin\"\n"
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"(symbol->string\n"
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" (string->symbol \"Malvina\")) @result{} \"Malvina\"\n"
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"@end lisp")
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#define FUNC_NAME s_scm_symbol_to_string
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{
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SCM_VALIDATE_SYMBOL (1, s);
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return scm_i_symbol_substring (s, 0, scm_i_symbol_length (s));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_string_to_symbol, "string->symbol", 1, 0, 0,
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(SCM string),
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"Return the symbol whose name is @var{string}. This procedure\n"
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"can create symbols with names containing special characters or\n"
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"letters in the non-standard case, but it is usually a bad idea\n"
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"to create such symbols because in some implementations of\n"
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"Scheme they cannot be read as themselves. See\n"
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"@code{symbol->string}.\n"
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"\n"
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"The following examples assume that the implementation's\n"
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"standard case is lower case:\n"
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"\n"
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"@lisp\n"
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"(eq? 'mISSISSIppi 'mississippi) @result{} #t\n"
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"(string->symbol \"mISSISSIppi\") @result{} @r{the symbol with name \"mISSISSIppi\"}\n"
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"(eq? 'bitBlt (string->symbol \"bitBlt\")) @result{} #f\n"
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"(eq? 'JollyWog\n"
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" (string->symbol (symbol->string 'JollyWog))) @result{} #t\n"
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"(string=? \"K. Harper, M.D.\"\n"
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" (symbol->string\n"
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" (string->symbol \"K. Harper, M.D.\"))) @result{}#t\n"
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"@end lisp")
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#define FUNC_NAME s_scm_string_to_symbol
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{
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SCM_VALIDATE_STRING (1, string);
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return scm_i_str2symbol (string);
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_string_ci_to_symbol, "string-ci->symbol", 1, 0, 0,
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(SCM str),
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"Return the symbol whose name is @var{str}. @var{str} is\n"
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"converted to lowercase before the conversion is done, if Guile\n"
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"is currently reading symbols case-insensitively.")
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#define FUNC_NAME s_scm_string_ci_to_symbol
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{
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return scm_string_to_symbol (SCM_CASE_INSENSITIVE_P
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? scm_string_downcase(str)
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: str);
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}
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#undef FUNC_NAME
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#define MAX_PREFIX_LENGTH 30
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SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0,
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(SCM prefix),
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"Create a new symbol with a name constructed from a prefix and\n"
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"a counter value. The string @var{prefix} can be specified as\n"
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"an optional argument. Default prefix is @code{ g}. The counter\n"
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"is increased by 1 at each call. There is no provision for\n"
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"resetting the counter.")
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#define FUNC_NAME s_scm_gensym
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{
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static int gensym_counter = 0;
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SCM suffix, name;
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int n, n_digits;
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char buf[SCM_INTBUFLEN];
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if (SCM_UNBNDP (prefix))
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prefix = scm_from_locale_string (" g");
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/* mutex in case another thread looks and incs at the exact same moment */
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scm_i_scm_pthread_mutex_lock (&scm_i_misc_mutex);
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n = gensym_counter++;
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scm_i_pthread_mutex_unlock (&scm_i_misc_mutex);
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n_digits = scm_iint2str (n, 10, buf);
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suffix = scm_from_locale_stringn (buf, n_digits);
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name = scm_string_append (scm_list_2 (prefix, suffix));
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return scm_string_to_symbol (name);
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_hash, "symbol-hash", 1, 0, 0,
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(SCM symbol),
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"Return a hash value for @var{symbol}.")
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#define FUNC_NAME s_scm_symbol_hash
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{
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SCM_VALIDATE_SYMBOL (1, symbol);
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return scm_from_ulong (scm_i_symbol_hash (symbol));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_fref, "symbol-fref", 1, 0, 0,
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(SCM s),
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"Return the contents of @var{symbol}'s @dfn{function slot}.")
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#define FUNC_NAME s_scm_symbol_fref
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{
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SCM_VALIDATE_SYMBOL (1, s);
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return SCM_CAR (SCM_CELL_OBJECT_3 (s));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_pref, "symbol-pref", 1, 0, 0,
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(SCM s),
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"Return the @dfn{property list} currently associated with @var{symbol}.")
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#define FUNC_NAME s_scm_symbol_pref
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{
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SCM_VALIDATE_SYMBOL (1, s);
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return SCM_CDR (SCM_CELL_OBJECT_3 (s));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_fset_x, "symbol-fset!", 2, 0, 0,
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(SCM s, SCM val),
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"Change the binding of @var{symbol}'s function slot.")
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#define FUNC_NAME s_scm_symbol_fset_x
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{
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SCM_VALIDATE_SYMBOL (1, s);
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SCM_SETCAR (SCM_CELL_OBJECT_3 (s), val);
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_symbol_pset_x, "symbol-pset!", 2, 0, 0,
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(SCM s, SCM val),
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"Change the binding of @var{symbol}'s property slot.")
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#define FUNC_NAME s_scm_symbol_pset_x
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{
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SCM_VALIDATE_SYMBOL (1, s);
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SCM_SETCDR (SCM_CELL_OBJECT_3 (s), val);
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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SCM
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scm_from_locale_symbol (const char *sym)
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{
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return scm_from_locale_symboln (sym, -1);
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}
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SCM
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scm_from_locale_symboln (const char *sym, size_t len)
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{
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SCM str = scm_from_locale_stringn (sym, len);
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return scm_i_str2symbol (str);
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}
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SCM
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scm_take_locale_symboln (char *sym, size_t len)
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{
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SCM str;
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str = scm_take_locale_stringn (sym, len);
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return scm_i_str2symbol (str);
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}
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SCM
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scm_take_locale_symbol (char *sym)
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{
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return scm_take_locale_symboln (sym, (size_t)-1);
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}
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void
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scm_symbols_prehistory ()
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{
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symbols = scm_make_weak_key_hash_table (scm_from_int (2139));
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}
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void
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scm_init_symbols ()
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{
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#include "libguile/symbols.x"
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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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