/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003, 2004, 2006, 2009 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 3 of * the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301 USA */ #ifdef HAVE_CONFIG_H # include #endif #include "libguile/_scm.h" #include "libguile/chars.h" #include "libguile/eval.h" #include "libguile/hash.h" #include "libguile/smob.h" #include "libguile/variable.h" #include "libguile/alist.h" #include "libguile/fluids.h" #include "libguile/strings.h" #include "libguile/vectors.h" #include "libguile/hashtab.h" #include "libguile/weaks.h" #include "libguile/modules.h" #include "libguile/read.h" #include "libguile/srfi-13.h" #include "libguile/validate.h" #include "libguile/symbols.h" #include "libguile/private-options.h" #ifdef HAVE_STRING_H #include #endif static SCM symbols; #ifdef GUILE_DEBUG SCM_DEFINE (scm_sys_symbols, "%symbols", 0, 0, 0, (), "Return the system symbol obarray.") #define FUNC_NAME s_scm_sys_symbols { return symbols; } #undef FUNC_NAME #endif /* {Symbols} */ /* In order to optimize reading speed, this function breaks part of * the hashtable abstraction. The optimizations are: * * 1. The argument string can be compared directly to symbol objects * without first creating an SCM string object. (This would have * been necessary if we had used the hashtable API in hashtab.h.) * * 2. We can use the raw hash value stored in scm_i_symbol_hash (sym) * to speed up lookup. * * Both optimizations might be possible without breaking the * abstraction if the API in hashtab.c is improved. */ unsigned long scm_i_hash_symbol (SCM obj, unsigned long n, void *closure) { return scm_i_symbol_hash (obj) % n; } static SCM lookup_interned_symbol (SCM name, unsigned long raw_hash) { /* Try to find the symbol in the symbols table */ SCM result = SCM_BOOL_F; SCM bucket, elt, previous_elt; size_t len; unsigned long hash = raw_hash % SCM_HASHTABLE_N_BUCKETS (symbols); len = scm_i_string_length (name); bucket = SCM_HASHTABLE_BUCKET (symbols, hash); for (elt = bucket, previous_elt = SCM_BOOL_F; !scm_is_null (elt); previous_elt = elt, elt = SCM_CDR (elt)) { SCM pair, sym; pair = SCM_CAR (elt); if (!scm_is_pair (pair)) abort (); if (SCM_WEAK_PAIR_CAR_DELETED_P (pair)) { /* PAIR is a weak pair whose key got nullified: remove it from BUCKET. */ /* FIXME: Since this is done lazily, i.e., only when a new symbol is to be inserted in a bucket containing deleted symbols, the number of items in the hash table may remain erroneous for some time, thus precluding proper rehashing. */ if (previous_elt != SCM_BOOL_F) SCM_SETCDR (previous_elt, SCM_CDR (elt)); else bucket = SCM_CDR (elt); SCM_HASHTABLE_DECREMENT (symbols); continue; } sym = SCM_CAR (pair); if (scm_i_symbol_hash (sym) == raw_hash && scm_i_symbol_length (sym) == len) { size_t i = len; /* Slightly faster path for comparing narrow to narrow. */ if (scm_i_is_narrow_string (name) && scm_i_is_narrow_symbol (sym)) { const char *chrs = scm_i_symbol_chars (sym); const char *str = scm_i_string_chars (name); while (i != 0) { --i; if (str[i] != chrs[i]) goto next_symbol; } } else { /* Somewhat slower path for comparing narrow to wide or wide to wide. */ while (i != 0) { --i; if (scm_i_string_ref (name, i) != scm_i_symbol_ref (sym, i)) goto next_symbol; } } /* We found it. */ result = sym; break; } next_symbol: ; } if (SCM_HASHTABLE_N_ITEMS (symbols) < SCM_HASHTABLE_LOWER (symbols)) /* We removed many symbols in this pass so trigger a rehashing. */ scm_i_rehash (symbols, scm_i_hash_symbol, 0, "lookup_interned_symbol"); return result; } /* Intern SYMBOL, an uninterned symbol. */ static void intern_symbol (SCM symbol) { SCM slot, cell; unsigned long hash; hash = scm_i_symbol_hash (symbol) % SCM_HASHTABLE_N_BUCKETS (symbols); slot = SCM_HASHTABLE_BUCKET (symbols, hash); cell = scm_cons (symbol, SCM_UNDEFINED); SCM_SET_HASHTABLE_BUCKET (symbols, hash, scm_cons (cell, slot)); SCM_HASHTABLE_INCREMENT (symbols); if (SCM_HASHTABLE_N_ITEMS (symbols) > SCM_HASHTABLE_UPPER (symbols)) scm_i_rehash (symbols, scm_i_hash_symbol, 0, "intern_symbol"); } static SCM scm_i_str2symbol (SCM str) { SCM symbol; size_t raw_hash = scm_i_string_hash (str); symbol = lookup_interned_symbol (str, raw_hash); if (scm_is_false (symbol)) { /* The symbol was not found, create it. */ symbol = scm_i_make_symbol (str, 0, raw_hash, scm_cons (SCM_BOOL_F, SCM_EOL)); intern_symbol (symbol); } return symbol; } static SCM scm_i_str2uninterned_symbol (SCM str) { size_t raw_hash = scm_i_string_hash (str); return scm_i_make_symbol (str, SCM_I_F_SYMBOL_UNINTERNED, raw_hash, scm_cons (SCM_BOOL_F, SCM_EOL)); } SCM_DEFINE (scm_symbol_p, "symbol?", 1, 0, 0, (SCM obj), "Return @code{#t} if @var{obj} is a symbol, otherwise return\n" "@code{#f}.") #define FUNC_NAME s_scm_symbol_p { return scm_from_bool (scm_is_symbol (obj)); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_interned_p, "symbol-interned?", 1, 0, 0, (SCM symbol), "Return @code{#t} if @var{symbol} is interned, otherwise return\n" "@code{#f}.") #define FUNC_NAME s_scm_symbol_interned_p { SCM_VALIDATE_SYMBOL (1, symbol); return scm_from_bool (scm_i_symbol_is_interned (symbol)); } #undef FUNC_NAME SCM_DEFINE (scm_make_symbol, "make-symbol", 1, 0, 0, (SCM name), "Return a new uninterned symbol with the name @var{name}. " "The returned symbol is guaranteed to be unique and future " "calls to @code{string->symbol} will not return it.") #define FUNC_NAME s_scm_make_symbol { SCM_VALIDATE_STRING (1, name); return scm_i_str2uninterned_symbol (name); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_to_string, "symbol->string", 1, 0, 0, (SCM s), "Return the name of @var{symbol} as a string. If the symbol was\n" "part of an object returned as the value of a literal expression\n" "(section @pxref{Literal expressions,,,r5rs, The Revised^5\n" "Report on Scheme}) or by a call to the @code{read} procedure,\n" "and its name contains alphabetic characters, then the string\n" "returned will contain characters in the implementation's\n" "preferred standard case---some implementations will prefer\n" "upper case, others lower case. If the symbol was returned by\n" "@code{string->symbol}, the case of characters in the string\n" "returned will be the same as the case in the string that was\n" "passed to @code{string->symbol}. It is an error to apply\n" "mutation procedures like @code{string-set!} to strings returned\n" "by this procedure.\n" "\n" "The following examples assume that the implementation's\n" "standard case is lower case:\n" "\n" "@lisp\n" "(symbol->string 'flying-fish) @result{} \"flying-fish\"\n" "(symbol->string 'Martin) @result{} \"martin\"\n" "(symbol->string\n" " (string->symbol \"Malvina\")) @result{} \"Malvina\"\n" "@end lisp") #define FUNC_NAME s_scm_symbol_to_string { SCM_VALIDATE_SYMBOL (1, s); return scm_i_symbol_substring (s, 0, scm_i_symbol_length (s)); } #undef FUNC_NAME SCM_DEFINE (scm_string_to_symbol, "string->symbol", 1, 0, 0, (SCM string), "Return the symbol whose name is @var{string}. This procedure\n" "can create symbols with names containing special characters or\n" "letters in the non-standard case, but it is usually a bad idea\n" "to create such symbols because in some implementations of\n" "Scheme they cannot be read as themselves. See\n" "@code{symbol->string}.\n" "\n" "The following examples assume that the implementation's\n" "standard case is lower case:\n" "\n" "@lisp\n" "(eq? 'mISSISSIppi 'mississippi) @result{} #t\n" "(string->symbol \"mISSISSIppi\") @result{} @r{the symbol with name \"mISSISSIppi\"}\n" "(eq? 'bitBlt (string->symbol \"bitBlt\")) @result{} #f\n" "(eq? 'JollyWog\n" " (string->symbol (symbol->string 'JollyWog))) @result{} #t\n" "(string=? \"K. Harper, M.D.\"\n" " (symbol->string\n" " (string->symbol \"K. Harper, M.D.\"))) @result{}#t\n" "@end lisp") #define FUNC_NAME s_scm_string_to_symbol { SCM_VALIDATE_STRING (1, string); return scm_i_str2symbol (string); } #undef FUNC_NAME SCM_DEFINE (scm_string_ci_to_symbol, "string-ci->symbol", 1, 0, 0, (SCM str), "Return the symbol whose name is @var{str}. @var{str} is\n" "converted to lowercase before the conversion is done, if Guile\n" "is currently reading symbols case-insensitively.") #define FUNC_NAME s_scm_string_ci_to_symbol { return scm_string_to_symbol (SCM_CASE_INSENSITIVE_P ? scm_string_downcase(str) : str); } #undef FUNC_NAME #define MAX_PREFIX_LENGTH 30 SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0, (SCM prefix), "Create a new symbol with a name constructed from a prefix and\n" "a counter value. The string @var{prefix} can be specified as\n" "an optional argument. Default prefix is @code{ g}. The counter\n" "is increased by 1 at each call. There is no provision for\n" "resetting the counter.") #define FUNC_NAME s_scm_gensym { static int gensym_counter = 0; SCM suffix, name; int n, n_digits; char buf[SCM_INTBUFLEN]; if (SCM_UNBNDP (prefix)) prefix = scm_from_locale_string (" g"); /* mutex in case another thread looks and incs at the exact same moment */ scm_i_scm_pthread_mutex_lock (&scm_i_misc_mutex); n = gensym_counter++; scm_i_pthread_mutex_unlock (&scm_i_misc_mutex); n_digits = scm_iint2str (n, 10, buf); suffix = scm_from_locale_stringn (buf, n_digits); name = scm_string_append (scm_list_2 (prefix, suffix)); return scm_string_to_symbol (name); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_hash, "symbol-hash", 1, 0, 0, (SCM symbol), "Return a hash value for @var{symbol}.") #define FUNC_NAME s_scm_symbol_hash { SCM_VALIDATE_SYMBOL (1, symbol); return scm_from_ulong (scm_i_symbol_hash (symbol)); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_fref, "symbol-fref", 1, 0, 0, (SCM s), "Return the contents of @var{symbol}'s @dfn{function slot}.") #define FUNC_NAME s_scm_symbol_fref { SCM_VALIDATE_SYMBOL (1, s); return SCM_CAR (SCM_CELL_OBJECT_3 (s)); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_pref, "symbol-pref", 1, 0, 0, (SCM s), "Return the @dfn{property list} currently associated with @var{symbol}.") #define FUNC_NAME s_scm_symbol_pref { SCM_VALIDATE_SYMBOL (1, s); return SCM_CDR (SCM_CELL_OBJECT_3 (s)); } #undef FUNC_NAME SCM_DEFINE (scm_symbol_fset_x, "symbol-fset!", 2, 0, 0, (SCM s, SCM val), "Change the binding of @var{symbol}'s function slot.") #define FUNC_NAME s_scm_symbol_fset_x { SCM_VALIDATE_SYMBOL (1, s); SCM_SETCAR (SCM_CELL_OBJECT_3 (s), val); return SCM_UNSPECIFIED; } #undef FUNC_NAME SCM_DEFINE (scm_symbol_pset_x, "symbol-pset!", 2, 0, 0, (SCM s, SCM val), "Change the binding of @var{symbol}'s property slot.") #define FUNC_NAME s_scm_symbol_pset_x { SCM_VALIDATE_SYMBOL (1, s); SCM_SETCDR (SCM_CELL_OBJECT_3 (s), val); return SCM_UNSPECIFIED; } #undef FUNC_NAME SCM scm_from_locale_symbol (const char *sym) { return scm_from_locale_symboln (sym, -1); } SCM scm_from_locale_symboln (const char *sym, size_t len) { SCM str = scm_from_locale_stringn (sym, len); return scm_i_str2symbol (str); } SCM scm_take_locale_symboln (char *sym, size_t len) { SCM str; str = scm_take_locale_stringn (sym, len); return scm_i_str2symbol (str); } SCM scm_take_locale_symbol (char *sym) { return scm_take_locale_symboln (sym, (size_t)-1); } void scm_symbols_prehistory () { symbols = scm_make_weak_key_hash_table (scm_from_int (2139)); } void scm_init_symbols () { #include "libguile/symbols.x" } /* Local Variables: c-file-style: "gnu" End: */