X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=guile18%2Flibguile%2Fenvironments.c;fp=guile18%2Flibguile%2Fenvironments.c;h=13d63c0353203fd78183dec211d3c3677d8091ad;hb=139c38d9204dd07f6b235f83bae644faedbc63fd;hp=0000000000000000000000000000000000000000;hpb=652ed35a2013489d0a14fede6307cd2595abb2c4;p=lilypond.git diff --git a/guile18/libguile/environments.c b/guile18/libguile/environments.c new file mode 100644 index 0000000000..13d63c0353 --- /dev/null +++ b/guile18/libguile/environments.c @@ -0,0 +1,2349 @@ +/* Copyright (C) 1999,2000,2001, 2003, 2006, 2008 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 2.1 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/alist.h" +#include "libguile/eval.h" +#include "libguile/gh.h" +#include "libguile/hash.h" +#include "libguile/list.h" +#include "libguile/ports.h" +#include "libguile/smob.h" +#include "libguile/symbols.h" +#include "libguile/vectors.h" +#include "libguile/weaks.h" + +#include "libguile/environments.h" + + + +scm_t_bits scm_tc16_environment; +scm_t_bits scm_tc16_observer; +#define DEFAULT_OBARRAY_SIZE 31 + +SCM scm_system_environment; + + + +/* error conditions */ + +/* + * Throw an error if symbol is not bound in environment func + */ +void +scm_error_environment_unbound (const char *func, SCM env, SCM symbol) +{ + /* Dirk:FIXME:: Should throw an environment:unbound type error */ + char error[] = "Symbol `~A' not bound in environment `~A'."; + SCM arguments = scm_cons2 (symbol, env, SCM_EOL); + scm_misc_error (func, error, arguments); +} + + +/* + * Throw an error if func tried to create (define) or remove + * (undefine) a new binding for symbol in env + */ +void +scm_error_environment_immutable_binding (const char *func, SCM env, SCM symbol) +{ + /* Dirk:FIXME:: Should throw an environment:immutable-binding type error */ + char error[] = "Immutable binding in environment ~A (symbol: `~A')."; + SCM arguments = scm_cons2 (env, symbol, SCM_EOL); + scm_misc_error (func, error, arguments); +} + + +/* + * Throw an error if func tried to change an immutable location. + */ +void +scm_error_environment_immutable_location (const char *func, SCM env, SCM symbol) +{ + /* Dirk:FIXME:: Should throw an environment:immutable-location type error */ + char error[] = "Immutable location in environment `~A' (symbol: `~A')."; + SCM arguments = scm_cons2 (env, symbol, SCM_EOL); + scm_misc_error (func, error, arguments); +} + + + +/* generic environments */ + + +/* Create an environment for the given type. Dereferencing type twice must + * deliver the initialized set of environment functions. Thus, type will + * also determine the signature of the underlying environment implementation. + * Dereferencing type once will typically deliver the data fields used by the + * underlying environment implementation. + */ +SCM +scm_make_environment (void *type) +{ + return scm_cell (scm_tc16_environment, (scm_t_bits) type); +} + + +SCM_DEFINE (scm_environment_p, "environment?", 1, 0, 0, + (SCM obj), + "Return @code{#t} if @var{obj} is an environment, or @code{#f}\n" + "otherwise.") +#define FUNC_NAME s_scm_environment_p +{ + return scm_from_bool (SCM_ENVIRONMENT_P (obj)); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_bound_p, "environment-bound?", 2, 0, 0, + (SCM env, SCM sym), + "Return @code{#t} if @var{sym} is bound in @var{env}, or\n" + "@code{#f} otherwise.") +#define FUNC_NAME s_scm_environment_bound_p +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, FUNC_NAME); + + return scm_from_bool (SCM_ENVIRONMENT_BOUND_P (env, sym)); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_ref, "environment-ref", 2, 0, 0, + (SCM env, SCM sym), + "Return the value of the location bound to @var{sym} in\n" + "@var{env}. If @var{sym} is unbound in @var{env}, signal an\n" + "@code{environment:unbound} error.") +#define FUNC_NAME s_scm_environment_ref +{ + SCM val; + + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, FUNC_NAME); + + val = SCM_ENVIRONMENT_REF (env, sym); + + if (!SCM_UNBNDP (val)) + return val; + else + scm_error_environment_unbound (FUNC_NAME, env, sym); +} +#undef FUNC_NAME + + +/* This C function is identical to environment-ref, except that if symbol is + * unbound in env, it returns the value SCM_UNDEFINED, instead of signalling + * an error. + */ +SCM +scm_c_environment_ref (SCM env, SCM sym) +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, "scm_c_environment_ref"); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, "scm_c_environment_ref"); + return SCM_ENVIRONMENT_REF (env, sym); +} + + +static SCM +environment_default_folder (SCM proc, SCM symbol, SCM value, SCM tail) +{ + return scm_call_3 (proc, symbol, value, tail); +} + + +SCM_DEFINE (scm_environment_fold, "environment-fold", 3, 0, 0, + (SCM env, SCM proc, SCM init), + "Iterate over all the bindings in @var{env}, accumulating some\n" + "value.\n" + "For each binding in @var{env}, apply @var{proc} to the symbol\n" + "bound, its value, and the result from the previous application\n" + "of @var{proc}.\n" + "Use @var{init} as @var{proc}'s third argument the first time\n" + "@var{proc} is applied.\n" + "If @var{env} contains no bindings, this function simply returns\n" + "@var{init}.\n" + "If @var{env} binds the symbol sym1 to the value val1, sym2 to\n" + "val2, and so on, then this procedure computes:\n" + "@lisp\n" + " (proc sym1 val1\n" + " (proc sym2 val2\n" + " ...\n" + " (proc symn valn\n" + " init)))\n" + "@end lisp\n" + "Each binding in @var{env} will be processed exactly once.\n" + "@code{environment-fold} makes no guarantees about the order in\n" + "which the bindings are processed.\n" + "Here is a function which, given an environment, constructs an\n" + "association list representing that environment's bindings,\n" + "using environment-fold:\n" + "@lisp\n" + " (define (environment->alist env)\n" + " (environment-fold env\n" + " (lambda (sym val tail)\n" + " (cons (cons sym val) tail))\n" + " '()))\n" + "@end lisp") +#define FUNC_NAME s_scm_environment_fold +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_true (scm_procedure_p (proc)), + proc, SCM_ARG2, FUNC_NAME); + + return SCM_ENVIRONMENT_FOLD (env, environment_default_folder, proc, init); +} +#undef FUNC_NAME + + +/* This is the C-level analog of environment-fold. For each binding in ENV, + * make the call: + * (*proc) (data, symbol, value, previous) + * where previous is the value returned from the last call to *PROC, or INIT + * for the first call. If ENV contains no bindings, return INIT. + */ +SCM +scm_c_environment_fold (SCM env, scm_environment_folder proc, SCM data, SCM init) +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, "scm_c_environment_fold"); + + return SCM_ENVIRONMENT_FOLD (env, proc, data, init); +} + + +SCM_DEFINE (scm_environment_define, "environment-define", 3, 0, 0, + (SCM env, SCM sym, SCM val), + "Bind @var{sym} to a new location containing @var{val} in\n" + "@var{env}. If @var{sym} is already bound to another location\n" + "in @var{env} and the binding is mutable, that binding is\n" + "replaced. The new binding and location are both mutable. The\n" + "return value is unspecified.\n" + "If @var{sym} is already bound in @var{env}, and the binding is\n" + "immutable, signal an @code{environment:immutable-binding} error.") +#define FUNC_NAME s_scm_environment_define +{ + SCM status; + + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, FUNC_NAME); + + status = SCM_ENVIRONMENT_DEFINE (env, sym, val); + + if (scm_is_eq (status, SCM_ENVIRONMENT_SUCCESS)) + return SCM_UNSPECIFIED; + else if (scm_is_eq (status, SCM_ENVIRONMENT_BINDING_IMMUTABLE)) + scm_error_environment_immutable_binding (FUNC_NAME, env, sym); + else + abort(); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_undefine, "environment-undefine", 2, 0, 0, + (SCM env, SCM sym), + "Remove any binding for @var{sym} from @var{env}. If @var{sym}\n" + "is unbound in @var{env}, do nothing. The return value is\n" + "unspecified.\n" + "If @var{sym} is already bound in @var{env}, and the binding is\n" + "immutable, signal an @code{environment:immutable-binding} error.") +#define FUNC_NAME s_scm_environment_undefine +{ + SCM status; + + SCM_ASSERT(SCM_ENVIRONMENT_P(env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT(scm_is_symbol(sym), sym, SCM_ARG2, FUNC_NAME); + + status = SCM_ENVIRONMENT_UNDEFINE (env, sym); + + if (scm_is_eq (status, SCM_ENVIRONMENT_SUCCESS)) + return SCM_UNSPECIFIED; + else if (scm_is_eq (status, SCM_ENVIRONMENT_BINDING_IMMUTABLE)) + scm_error_environment_immutable_binding (FUNC_NAME, env, sym); + else + abort(); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_set_x, "environment-set!", 3, 0, 0, + (SCM env, SCM sym, SCM val), + "If @var{env} binds @var{sym} to some location, change that\n" + "location's value to @var{val}. The return value is\n" + "unspecified.\n" + "If @var{sym} is not bound in @var{env}, signal an\n" + "@code{environment:unbound} error. If @var{env} binds @var{sym}\n" + "to an immutable location, signal an\n" + "@code{environment:immutable-location} error.") +#define FUNC_NAME s_scm_environment_set_x +{ + SCM status; + + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, FUNC_NAME); + + status = SCM_ENVIRONMENT_SET (env, sym, val); + + if (scm_is_eq (status, SCM_ENVIRONMENT_SUCCESS)) + return SCM_UNSPECIFIED; + else if (SCM_UNBNDP (status)) + scm_error_environment_unbound (FUNC_NAME, env, sym); + else if (scm_is_eq (status, SCM_ENVIRONMENT_LOCATION_IMMUTABLE)) + scm_error_environment_immutable_binding (FUNC_NAME, env, sym); + else + abort(); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_cell, "environment-cell", 3, 0, 0, + (SCM env, SCM sym, SCM for_write), + "Return the value cell which @var{env} binds to @var{sym}, or\n" + "@code{#f} if the binding does not live in a value cell.\n" + "The argument @var{for-write} indicates whether the caller\n" + "intends to modify the variable's value by mutating the value\n" + "cell. If the variable is immutable, then\n" + "@code{environment-cell} signals an\n" + "@code{environment:immutable-location} error.\n" + "If @var{sym} is unbound in @var{env}, signal an\n" + "@code{environment:unbound} error.\n" + "If you use this function, you should consider using\n" + "@code{environment-observe}, to be notified when @var{sym} gets\n" + "re-bound to a new value cell, or becomes undefined.") +#define FUNC_NAME s_scm_environment_cell +{ + SCM location; + + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, FUNC_NAME); + SCM_ASSERT (scm_is_bool (for_write), for_write, SCM_ARG3, FUNC_NAME); + + location = SCM_ENVIRONMENT_CELL (env, sym, scm_is_true (for_write)); + if (!SCM_IMP (location)) + return location; + else if (SCM_UNBNDP (location)) + scm_error_environment_unbound (FUNC_NAME, env, sym); + else if (scm_is_eq (location, SCM_ENVIRONMENT_LOCATION_IMMUTABLE)) + scm_error_environment_immutable_location (FUNC_NAME, env, sym); + else /* no cell */ + return location; +} +#undef FUNC_NAME + + +/* This C function is identical to environment-cell, with the following + * exceptions: If symbol is unbound in env, it returns the value + * SCM_UNDEFINED, instead of signalling an error. If symbol is bound to an + * immutable location but the cell is requested for write, the value + * SCM_ENVIRONMENT_LOCATION_IMMUTABLE is returned. + */ +SCM +scm_c_environment_cell(SCM env, SCM sym, int for_write) +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, "scm_c_environment_cell"); + SCM_ASSERT (scm_is_symbol (sym), sym, SCM_ARG2, "scm_c_environment_cell"); + + return SCM_ENVIRONMENT_CELL (env, sym, for_write); +} + + +static void +environment_default_observer (SCM env, SCM proc) +{ + scm_call_1 (proc, env); +} + + +SCM_DEFINE (scm_environment_observe, "environment-observe", 2, 0, 0, + (SCM env, SCM proc), + "Whenever @var{env}'s bindings change, apply @var{proc} to\n" + "@var{env}.\n" + "This function returns an object, token, which you can pass to\n" + "@code{environment-unobserve} to remove @var{proc} from the set\n" + "of procedures observing @var{env}. The type and value of\n" + "token is unspecified.") +#define FUNC_NAME s_scm_environment_observe +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return SCM_ENVIRONMENT_OBSERVE (env, environment_default_observer, proc, 0); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_observe_weak, "environment-observe-weak", 2, 0, 0, + (SCM env, SCM proc), + "This function is the same as environment-observe, except that\n" + "the reference @var{env} retains to @var{proc} is a weak\n" + "reference. This means that, if there are no other live,\n" + "non-weak references to @var{proc}, it will be\n" + "garbage-collected, and dropped from @var{env}'s\n" + "list of observing procedures.") +#define FUNC_NAME s_scm_environment_observe_weak +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return SCM_ENVIRONMENT_OBSERVE (env, environment_default_observer, proc, 1); +} +#undef FUNC_NAME + + +/* This is the C-level analog of the Scheme functions environment-observe and + * environment-observe-weak. Whenever env's bindings change, call the + * function proc, passing it env and data. If weak_p is non-zero, env will + * retain only a weak reference to data, and if data is garbage collected, the + * entire observation will be dropped. This function returns a token, with + * the same meaning as those returned by environment-observe and + * environment-observe-weak. + */ +SCM +scm_c_environment_observe (SCM env, scm_environment_observer proc, SCM data, int weak_p) +#define FUNC_NAME "scm_c_environment_observe" +{ + SCM_ASSERT (SCM_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return SCM_ENVIRONMENT_OBSERVE (env, proc, data, weak_p); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_environment_unobserve, "environment-unobserve", 1, 0, 0, + (SCM token), + "Cancel the observation request which returned the value\n" + "@var{token}. The return value is unspecified.\n" + "If a call @code{(environment-observe env proc)} returns\n" + "@var{token}, then the call @code{(environment-unobserve token)}\n" + "will cause @var{proc} to no longer be called when @var{env}'s\n" + "bindings change.") +#define FUNC_NAME s_scm_environment_unobserve +{ + SCM env; + + SCM_ASSERT (SCM_OBSERVER_P (token), token, SCM_ARG1, FUNC_NAME); + + env = SCM_OBSERVER_ENVIRONMENT (token); + SCM_ENVIRONMENT_UNOBSERVE (env, token); + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + +static SCM +environment_mark (SCM env) +{ + return (*(SCM_ENVIRONMENT_FUNCS (env)->mark)) (env); +} + + +static size_t +environment_free (SCM env) +{ + (*(SCM_ENVIRONMENT_FUNCS (env)->free)) (env); + return 0; +} + + +static int +environment_print (SCM env, SCM port, scm_print_state *pstate) +{ + return (*(SCM_ENVIRONMENT_FUNCS (env)->print)) (env, port, pstate); +} + + + +/* observers */ + +static SCM +observer_mark (SCM observer) +{ + scm_gc_mark (SCM_OBSERVER_ENVIRONMENT (observer)); + scm_gc_mark (SCM_OBSERVER_DATA (observer)); + return SCM_BOOL_F; +} + + +static int +observer_print (SCM type, SCM port, scm_print_state *pstate SCM_UNUSED) +{ + SCM address = scm_from_size_t (SCM_UNPACK (type)); + SCM base16 = scm_number_to_string (address, scm_from_int (16)); + + scm_puts ("#", port); + + return 1; +} + + + +/* obarrays + * + * Obarrays form the basic lookup tables used to implement most of guile's + * built-in environment types. An obarray is implemented as a hash table with + * symbols as keys. The content of the data depends on the environment type. + */ + + +/* + * Enter symbol into obarray. The symbol must not already exist in obarray. + * The freshly generated (symbol . data) cell is returned. + */ +static SCM +obarray_enter (SCM obarray, SCM symbol, SCM data) +{ + size_t hash = scm_i_symbol_hash (symbol) % SCM_HASHTABLE_N_BUCKETS (obarray); + SCM entry = scm_cons (symbol, data); + SCM slot = scm_cons (entry, SCM_HASHTABLE_BUCKET (obarray, hash)); + SCM_SET_HASHTABLE_BUCKET (obarray, hash, slot); + SCM_HASHTABLE_INCREMENT (obarray); + if (SCM_HASHTABLE_N_ITEMS (obarray) > SCM_HASHTABLE_UPPER (obarray)) + scm_i_rehash (obarray, scm_i_hash_symbol, 0, "obarray_enter"); + + return entry; +} + + +/* + * Enter symbol into obarray. An existing entry for symbol is replaced. If + * an entry existed, the old (symbol . data) cell is returned, #f otherwise. + */ +static SCM +obarray_replace (SCM obarray, SCM symbol, SCM data) +{ + size_t hash = scm_i_symbol_hash (symbol) % SCM_HASHTABLE_N_BUCKETS (obarray); + SCM new_entry = scm_cons (symbol, data); + SCM lsym; + SCM slot; + + for (lsym = SCM_HASHTABLE_BUCKET (obarray, hash); + !scm_is_null (lsym); + lsym = SCM_CDR (lsym)) + { + SCM old_entry = SCM_CAR (lsym); + if (scm_is_eq (SCM_CAR (old_entry), symbol)) + { + SCM_SETCAR (lsym, new_entry); + return old_entry; + } + } + + slot = scm_cons (new_entry, SCM_HASHTABLE_BUCKET (obarray, hash)); + SCM_SET_HASHTABLE_BUCKET (obarray, hash, slot); + SCM_HASHTABLE_INCREMENT (obarray); + if (SCM_HASHTABLE_N_ITEMS (obarray) > SCM_HASHTABLE_UPPER (obarray)) + scm_i_rehash (obarray, scm_i_hash_symbol, 0, "obarray_replace"); + + return SCM_BOOL_F; +} + + +/* + * Look up symbol in obarray + */ +static SCM +obarray_retrieve (SCM obarray, SCM sym) +{ + size_t hash = scm_i_symbol_hash (sym) % SCM_HASHTABLE_N_BUCKETS (obarray); + SCM lsym; + + for (lsym = SCM_HASHTABLE_BUCKET (obarray, hash); + !scm_is_null (lsym); + lsym = SCM_CDR (lsym)) + { + SCM entry = SCM_CAR (lsym); + if (scm_is_eq (SCM_CAR (entry), sym)) + return entry; + } + + return SCM_UNDEFINED; +} + + +/* + * Remove entry from obarray. If the symbol was found and removed, the old + * (symbol . data) cell is returned, #f otherwise. + */ +static SCM +obarray_remove (SCM obarray, SCM sym) +{ + size_t hash = scm_i_symbol_hash (sym) % SCM_HASHTABLE_N_BUCKETS (obarray); + SCM table_entry = SCM_HASHTABLE_BUCKET (obarray, hash); + SCM handle = scm_sloppy_assq (sym, table_entry); + + if (scm_is_pair (handle)) + { + SCM new_table_entry = scm_delq1_x (handle, table_entry); + SCM_SET_HASHTABLE_BUCKET (obarray, hash, new_table_entry); + SCM_HASHTABLE_DECREMENT (obarray); + } + + return handle; +} + + +static void +obarray_remove_all (SCM obarray) +{ + size_t size = SCM_HASHTABLE_N_BUCKETS (obarray); + size_t i; + + for (i = 0; i < size; i++) + { + SCM_SET_HASHTABLE_BUCKET (obarray, i, SCM_EOL); + } + SCM_SET_HASHTABLE_N_ITEMS (obarray, 0); +} + + + +/* core environments base + * + * This struct and the corresponding functions form a base class for guile's + * built-in environment types. + */ + + +struct core_environments_base { + struct scm_environment_funcs *funcs; + + SCM observers; + SCM weak_observers; +}; + + +#define CORE_ENVIRONMENTS_BASE(env) \ + ((struct core_environments_base *) SCM_CELL_WORD_1 (env)) +#define CORE_ENVIRONMENT_OBSERVERS(env) \ + (CORE_ENVIRONMENTS_BASE (env)->observers) +#define SCM_SET_CORE_ENVIRONMENT_OBSERVERS(env, v) \ + (CORE_ENVIRONMENT_OBSERVERS (env) = (v)) +#define CORE_ENVIRONMENT_WEAK_OBSERVER_VECTOR(env) \ + (CORE_ENVIRONMENTS_BASE (env)->weak_observers) +#define CORE_ENVIRONMENT_WEAK_OBSERVERS(env) \ + (scm_c_vector_ref (CORE_ENVIRONMENT_WEAK_OBSERVER_VECTOR (env), 0)) +#define SCM_SET_CORE_ENVIRONMENT_WEAK_OBSERVERS(env, v) \ + (scm_c_vector_set_x (CORE_ENVIRONMENT_WEAK_OBSERVER_VECTOR (env), 0, (v))) + + + +static SCM +core_environments_observe (SCM env, scm_environment_observer proc, SCM data, int weak_p) +{ + SCM observer = scm_double_cell (scm_tc16_observer, + SCM_UNPACK (env), + SCM_UNPACK (data), + (scm_t_bits) proc); + + if (!weak_p) + { + SCM observers = CORE_ENVIRONMENT_OBSERVERS (env); + SCM new_observers = scm_cons (observer, observers); + SCM_SET_CORE_ENVIRONMENT_OBSERVERS (env, new_observers); + } + else + { + SCM observers = CORE_ENVIRONMENT_WEAK_OBSERVERS (env); + SCM new_observers = scm_acons (SCM_BOOL_F, observer, observers); + SCM_SET_CORE_ENVIRONMENT_WEAK_OBSERVERS (env, new_observers); + } + + return observer; +} + + +static void +core_environments_unobserve (SCM env, SCM observer) +{ + unsigned int handling_weaks; + for (handling_weaks = 0; handling_weaks <= 1; ++handling_weaks) + { + SCM l = handling_weaks + ? CORE_ENVIRONMENT_WEAK_OBSERVERS (env) + : CORE_ENVIRONMENT_OBSERVERS (env); + + if (!scm_is_null (l)) + { + SCM rest = SCM_CDR (l); + SCM first = handling_weaks + ? SCM_CDAR (l) + : SCM_CAR (l); + + if (scm_is_eq (first, observer)) + { + /* Remove the first observer */ + if (handling_weaks) + SCM_SET_CORE_ENVIRONMENT_WEAK_OBSERVERS (env, rest); + else + SCM_SET_CORE_ENVIRONMENT_OBSERVERS (env, rest); + return; + } + + do { + SCM rest = SCM_CDR (l); + + if (!scm_is_null (rest)) + { + SCM next = handling_weaks + ? SCM_CDAR (l) + : SCM_CAR (l); + + if (scm_is_eq (next, observer)) + { + SCM_SETCDR (l, SCM_CDR (rest)); + return; + } + } + + l = rest; + } while (!scm_is_null (l)); + } + } + + /* Dirk:FIXME:: What to do now, since the observer is not found? */ +} + + +static SCM +core_environments_mark (SCM env) +{ + scm_gc_mark (CORE_ENVIRONMENT_OBSERVERS (env)); + return CORE_ENVIRONMENT_WEAK_OBSERVER_VECTOR (env); +} + + +static void +core_environments_finalize (SCM env SCM_UNUSED) +{ +} + + +static void +core_environments_preinit (struct core_environments_base *body) +{ + body->funcs = NULL; + body->observers = SCM_BOOL_F; + body->weak_observers = SCM_BOOL_F; +} + + +static void +core_environments_init (struct core_environments_base *body, + struct scm_environment_funcs *funcs) +{ + body->funcs = funcs; + body->observers = SCM_EOL; + body->weak_observers = scm_make_weak_value_alist_vector (scm_from_int (1)); +} + + +/* Tell all observers to clear their caches. + * + * Environments have to be informed about changes in the following cases: + * - The observed env has a new binding. This must be always reported. + * - The observed env has dropped a binding. This must be always reported. + * - A binding in the observed environment has changed. This must only be + * reported, if there is a chance that the binding is being cached outside. + * However, this potential optimization is not performed currently. + * + * Errors that occur while the observers are called are accumulated and + * signalled as one single error message to the caller. + */ + +struct update_data +{ + SCM observer; + SCM environment; +}; + + +static SCM +update_catch_body (void *ptr) +{ + struct update_data *data = (struct update_data *) ptr; + SCM observer = data->observer; + + (*SCM_OBSERVER_PROC (observer)) + (data->environment, SCM_OBSERVER_DATA (observer)); + + return SCM_UNDEFINED; +} + + +static SCM +update_catch_handler (void *ptr, SCM tag, SCM args) +{ + struct update_data *data = (struct update_data *) ptr; + SCM observer = data->observer; + SCM message = + scm_from_locale_string ("Observer `~A' signals `~A' error: ~S"); + + return scm_cons (message, scm_list_3 (observer, tag, args)); +} + + +static void +core_environments_broadcast (SCM env) +#define FUNC_NAME "core_environments_broadcast" +{ + unsigned int handling_weaks; + SCM errors = SCM_EOL; + + for (handling_weaks = 0; handling_weaks <= 1; ++handling_weaks) + { + SCM observers = handling_weaks + ? CORE_ENVIRONMENT_WEAK_OBSERVERS (env) + : CORE_ENVIRONMENT_OBSERVERS (env); + + for (; !scm_is_null (observers); observers = SCM_CDR (observers)) + { + struct update_data data; + SCM observer = handling_weaks + ? SCM_CDAR (observers) + : SCM_CAR (observers); + SCM error; + + data.observer = observer; + data.environment = env; + + error = scm_internal_catch (SCM_BOOL_T, + update_catch_body, &data, + update_catch_handler, &data); + + if (!SCM_UNBNDP (error)) + errors = scm_cons (error, errors); + } + } + + if (!scm_is_null (errors)) + { + /* Dirk:FIXME:: As soon as scm_misc_error is fixed to handle the name + * parameter correctly it should not be necessary any more to also pass + * namestr in order to get the desired information from the error + * message. + */ + SCM ordered_errors = scm_reverse (errors); + scm_misc_error + (FUNC_NAME, + "Observers of `~A' have signalled the following errors: ~S", + scm_cons2 (env, ordered_errors, SCM_EOL)); + } +} +#undef FUNC_NAME + + + +/* leaf environments + * + * A leaf environment is simply a mutable set of definitions. A leaf + * environment supports no operations beyond the common set. + * + * Implementation: The obarray of the leaf environment holds (symbol . value) + * pairs. No further information is necessary, since all bindings and + * locations in a leaf environment are mutable. + */ + + +struct leaf_environment { + struct core_environments_base base; + + SCM obarray; +}; + + +#define LEAF_ENVIRONMENT(env) \ + ((struct leaf_environment *) SCM_CELL_WORD_1 (env)) + + + +static SCM +leaf_environment_ref (SCM env, SCM sym) +{ + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + SCM binding = obarray_retrieve (obarray, sym); + return SCM_UNBNDP (binding) ? binding : SCM_CDR (binding); +} + + +static SCM +leaf_environment_fold (SCM env, scm_environment_folder proc, SCM data, SCM init) +{ + size_t i; + SCM result = init; + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + + for (i = 0; i < SCM_HASHTABLE_N_BUCKETS (obarray); i++) + { + SCM l; + for (l = SCM_HASHTABLE_BUCKET (obarray, i); + !scm_is_null (l); + l = SCM_CDR (l)) + { + SCM binding = SCM_CAR (l); + SCM symbol = SCM_CAR (binding); + SCM value = SCM_CDR (binding); + result = (*proc) (data, symbol, value, result); + } + } + return result; +} + + +static SCM +leaf_environment_define (SCM env, SCM sym, SCM val) +#define FUNC_NAME "leaf_environment_define" +{ + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + + obarray_replace (obarray, sym, val); + core_environments_broadcast (env); + + return SCM_ENVIRONMENT_SUCCESS; +} +#undef FUNC_NAME + + +static SCM +leaf_environment_undefine (SCM env, SCM sym) +#define FUNC_NAME "leaf_environment_undefine" +{ + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + SCM removed = obarray_remove (obarray, sym); + + if (scm_is_true (removed)) + core_environments_broadcast (env); + + return SCM_ENVIRONMENT_SUCCESS; +} +#undef FUNC_NAME + + +static SCM +leaf_environment_set_x (SCM env, SCM sym, SCM val) +#define FUNC_NAME "leaf_environment_set_x" +{ + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + SCM binding = obarray_retrieve (obarray, sym); + + if (!SCM_UNBNDP (binding)) + { + SCM_SETCDR (binding, val); + return SCM_ENVIRONMENT_SUCCESS; + } + else + { + return SCM_UNDEFINED; + } +} +#undef FUNC_NAME + + +static SCM +leaf_environment_cell (SCM env, SCM sym, int for_write SCM_UNUSED) +{ + SCM obarray = LEAF_ENVIRONMENT (env)->obarray; + SCM binding = obarray_retrieve (obarray, sym); + return binding; +} + + +static SCM +leaf_environment_mark (SCM env) +{ + scm_gc_mark (LEAF_ENVIRONMENT (env)->obarray); + return core_environments_mark (env); +} + + +static void +leaf_environment_free (SCM env) +{ + core_environments_finalize (env); + scm_gc_free (LEAF_ENVIRONMENT (env), sizeof (struct leaf_environment), + "leaf environment"); +} + + +static int +leaf_environment_print (SCM type, SCM port, scm_print_state *pstate SCM_UNUSED) +{ + SCM address = scm_from_size_t (SCM_UNPACK (type)); + SCM base16 = scm_number_to_string (address, scm_from_int (16)); + + scm_puts ("#", port); + + return 1; +} + + +static struct scm_environment_funcs leaf_environment_funcs = { + leaf_environment_ref, + leaf_environment_fold, + leaf_environment_define, + leaf_environment_undefine, + leaf_environment_set_x, + leaf_environment_cell, + core_environments_observe, + core_environments_unobserve, + leaf_environment_mark, + leaf_environment_free, + leaf_environment_print +}; + + +void *scm_type_leaf_environment = &leaf_environment_funcs; + + +SCM_DEFINE (scm_make_leaf_environment, "make-leaf-environment", 0, 0, 0, + (), + "Create a new leaf environment, containing no bindings.\n" + "All bindings and locations created in the new environment\n" + "will be mutable.") +#define FUNC_NAME s_scm_make_leaf_environment +{ + size_t size = sizeof (struct leaf_environment); + struct leaf_environment *body = scm_gc_malloc (size, "leaf environment"); + SCM env; + + core_environments_preinit (&body->base); + body->obarray = SCM_BOOL_F; + + env = scm_make_environment (body); + + core_environments_init (&body->base, &leaf_environment_funcs); + body->obarray = scm_c_make_hash_table (DEFAULT_OBARRAY_SIZE); + + return env; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_leaf_environment_p, "leaf-environment?", 1, 0, 0, + (SCM object), + "Return @code{#t} if object is a leaf environment, or @code{#f}\n" + "otherwise.") +#define FUNC_NAME s_scm_leaf_environment_p +{ + return scm_from_bool (SCM_LEAF_ENVIRONMENT_P (object)); +} +#undef FUNC_NAME + + + +/* eval environments + * + * A module's source code refers to definitions imported from other modules, + * and definitions made within itself. An eval environment combines two + * environments -- a local environment and an imported environment -- to + * produce a new environment in which both sorts of references can be + * resolved. + * + * Implementation: The obarray of the eval environment is used to cache + * entries from the local and imported environments such that in most of the + * cases only a single lookup is necessary. Since for neither the local nor + * the imported environment it is known, what kind of environment they form, + * the most general case is assumed. Therefore, entries in the obarray take + * one of the following forms: + * + * 1) ( location mutability . source-env), where mutability indicates + * one of the following states: IMMUTABLE if the location is known to be + * immutable, MUTABLE if the location is known to be mutable, UNKNOWN if + * the location has only been requested for non modifying accesses. + * + * 2) (symbol . source-env) if the symbol has a binding in the source-env, but + * if the source-env can't provide a cell for the binding. Thus, for every + * access, the source-env has to be contacted directly. + */ + + +struct eval_environment { + struct core_environments_base base; + + SCM obarray; + + SCM imported; + SCM imported_observer; + SCM local; + SCM local_observer; +}; + + +#define EVAL_ENVIRONMENT(env) \ + ((struct eval_environment *) SCM_CELL_WORD_1 (env)) + +#define IMMUTABLE SCM_I_MAKINUM (0) +#define MUTABLE SCM_I_MAKINUM (1) +#define UNKNOWN SCM_I_MAKINUM (2) + +#define CACHED_LOCATION(x) SCM_CAR (x) +#define CACHED_MUTABILITY(x) SCM_CADR (x) +#define SET_CACHED_MUTABILITY(x, v) SCM_SETCAR (SCM_CDR (x), (v)) +#define CACHED_SOURCE_ENVIRONMENT(x) SCM_CDDR (x) + + + +/* eval_environment_lookup will report one of the following distinct results: + * a) ( . value) if a cell could be obtained. + * b) if the environment has to be contacted directly. + * c) IMMUTABLE if an immutable cell was requested for write. + * d) SCM_UNDEFINED if there is no binding for the symbol. + */ +static SCM +eval_environment_lookup (SCM env, SCM sym, int for_write) +{ + SCM obarray = EVAL_ENVIRONMENT (env)->obarray; + SCM binding = obarray_retrieve (obarray, sym); + + if (!SCM_UNBNDP (binding)) + { + /* The obarray holds an entry for the symbol. */ + + SCM entry = SCM_CDR (binding); + + if (scm_is_pair (entry)) + { + /* The entry in the obarray is a cached location. */ + + SCM location = CACHED_LOCATION (entry); + SCM mutability; + + if (!for_write) + return location; + + mutability = CACHED_MUTABILITY (entry); + if (scm_is_eq (mutability, MUTABLE)) + return location; + + if (scm_is_eq (mutability, UNKNOWN)) + { + SCM source_env = CACHED_SOURCE_ENVIRONMENT (entry); + SCM location = SCM_ENVIRONMENT_CELL (source_env, sym, 1); + + if (scm_is_pair (location)) + { + SET_CACHED_MUTABILITY (entry, MUTABLE); + return location; + } + else /* IMMUTABLE */ + { + SET_CACHED_MUTABILITY (entry, IMMUTABLE); + return IMMUTABLE; + } + } + + return IMMUTABLE; + } + else + { + /* The obarray entry is an environment */ + + return entry; + } + } + else + { + /* There is no entry for the symbol in the obarray. This can either + * mean that there has not been a request for the symbol yet, or that + * the symbol is really undefined. We are looking for the symbol in + * both the local and the imported environment. If we find a binding, a + * cached entry is created. + */ + + struct eval_environment *body = EVAL_ENVIRONMENT (env); + unsigned int handling_import; + + for (handling_import = 0; handling_import <= 1; ++handling_import) + { + SCM source_env = handling_import ? body->imported : body->local; + SCM location = SCM_ENVIRONMENT_CELL (source_env, sym, for_write); + + if (!SCM_UNBNDP (location)) + { + if (scm_is_pair (location)) + { + SCM mutability = for_write ? MUTABLE : UNKNOWN; + SCM entry = scm_cons2 (location, mutability, source_env); + obarray_enter (obarray, sym, entry); + return location; + } + else if (scm_is_eq (location, SCM_ENVIRONMENT_LOCATION_NO_CELL)) + { + obarray_enter (obarray, sym, source_env); + return source_env; + } + else + { + return IMMUTABLE; + } + } + } + + return SCM_UNDEFINED; + } +} + + +static SCM +eval_environment_ref (SCM env, SCM sym) +#define FUNC_NAME "eval_environment_ref" +{ + SCM location = eval_environment_lookup (env, sym, 0); + + if (scm_is_pair (location)) + return SCM_CDR (location); + else if (!SCM_UNBNDP (location)) + return SCM_ENVIRONMENT_REF (location, sym); + else + return SCM_UNDEFINED; +} +#undef FUNC_NAME + + +static SCM +eval_environment_folder (SCM extended_data, SCM symbol, SCM value, SCM tail) +{ + SCM local = SCM_CAR (extended_data); + + if (!SCM_ENVIRONMENT_BOUND_P (local, symbol)) + { + SCM proc_as_nr = SCM_CADR (extended_data); + unsigned long int proc_as_ul = scm_to_ulong (proc_as_nr); + scm_environment_folder proc = (scm_environment_folder) proc_as_ul; + SCM data = SCM_CDDR (extended_data); + + return (*proc) (data, symbol, value, tail); + } + else + { + return tail; + } +} + + +static SCM +eval_environment_fold (SCM env, scm_environment_folder proc, SCM data, SCM init) +{ + SCM local = EVAL_ENVIRONMENT (env)->local; + SCM imported = EVAL_ENVIRONMENT (env)->imported; + SCM proc_as_nr = scm_from_ulong ((unsigned long) proc); + SCM extended_data = scm_cons2 (local, proc_as_nr, data); + SCM tmp_result = scm_c_environment_fold (imported, eval_environment_folder, extended_data, init); + + return scm_c_environment_fold (local, proc, data, tmp_result); +} + + +static SCM +eval_environment_define (SCM env, SCM sym, SCM val) +#define FUNC_NAME "eval_environment_define" +{ + SCM local = EVAL_ENVIRONMENT (env)->local; + return SCM_ENVIRONMENT_DEFINE (local, sym, val); +} +#undef FUNC_NAME + + +static SCM +eval_environment_undefine (SCM env, SCM sym) +#define FUNC_NAME "eval_environment_undefine" +{ + SCM local = EVAL_ENVIRONMENT (env)->local; + return SCM_ENVIRONMENT_UNDEFINE (local, sym); +} +#undef FUNC_NAME + + +static SCM +eval_environment_set_x (SCM env, SCM sym, SCM val) +#define FUNC_NAME "eval_environment_set_x" +{ + SCM location = eval_environment_lookup (env, sym, 1); + + if (scm_is_pair (location)) + { + SCM_SETCDR (location, val); + return SCM_ENVIRONMENT_SUCCESS; + } + else if (SCM_ENVIRONMENT_P (location)) + { + return SCM_ENVIRONMENT_SET (location, sym, val); + } + else if (scm_is_eq (location, IMMUTABLE)) + { + return SCM_ENVIRONMENT_LOCATION_IMMUTABLE; + } + else + { + return SCM_UNDEFINED; + } +} +#undef FUNC_NAME + + +static SCM +eval_environment_cell (SCM env, SCM sym, int for_write) +#define FUNC_NAME "eval_environment_cell" +{ + SCM location = eval_environment_lookup (env, sym, for_write); + + if (scm_is_pair (location)) + return location; + else if (SCM_ENVIRONMENT_P (location)) + return SCM_ENVIRONMENT_LOCATION_NO_CELL; + else if (scm_is_eq (location, IMMUTABLE)) + return SCM_ENVIRONMENT_LOCATION_IMMUTABLE; + else + return SCM_UNDEFINED; +} +#undef FUNC_NAME + + +static SCM +eval_environment_mark (SCM env) +{ + struct eval_environment *body = EVAL_ENVIRONMENT (env); + + scm_gc_mark (body->obarray); + scm_gc_mark (body->imported); + scm_gc_mark (body->imported_observer); + scm_gc_mark (body->local); + scm_gc_mark (body->local_observer); + + return core_environments_mark (env); +} + + +static void +eval_environment_free (SCM env) +{ + core_environments_finalize (env); + scm_gc_free (EVAL_ENVIRONMENT (env), sizeof (struct eval_environment), + "eval environment"); +} + + +static int +eval_environment_print (SCM type, SCM port, scm_print_state *pstate SCM_UNUSED) +{ + SCM address = scm_from_size_t (SCM_UNPACK (type)); + SCM base16 = scm_number_to_string (address, scm_from_int (16)); + + scm_puts ("#", port); + + return 1; +} + + +static struct scm_environment_funcs eval_environment_funcs = { + eval_environment_ref, + eval_environment_fold, + eval_environment_define, + eval_environment_undefine, + eval_environment_set_x, + eval_environment_cell, + core_environments_observe, + core_environments_unobserve, + eval_environment_mark, + eval_environment_free, + eval_environment_print +}; + + +void *scm_type_eval_environment = &eval_environment_funcs; + + +static void +eval_environment_observer (SCM caller SCM_UNUSED, SCM eval_env) +{ + SCM obarray = EVAL_ENVIRONMENT (eval_env)->obarray; + + obarray_remove_all (obarray); + core_environments_broadcast (eval_env); +} + + +SCM_DEFINE (scm_make_eval_environment, "make-eval-environment", 2, 0, 0, + (SCM local, SCM imported), + "Return a new environment object eval whose bindings are the\n" + "union of the bindings in the environments @var{local} and\n" + "@var{imported}, with bindings from @var{local} taking\n" + "precedence. Definitions made in eval are placed in @var{local}.\n" + "Applying @code{environment-define} or\n" + "@code{environment-undefine} to eval has the same effect as\n" + "applying the procedure to @var{local}.\n" + "Note that eval incorporates @var{local} and @var{imported} by\n" + "reference:\n" + "If, after creating eval, the program changes the bindings of\n" + "@var{local} or @var{imported}, those changes will be visible\n" + "in eval.\n" + "Since most Scheme evaluation takes place in eval environments,\n" + "they transparently cache the bindings received from @var{local}\n" + "and @var{imported}. Thus, the first time the program looks up\n" + "a symbol in eval, eval may make calls to @var{local} or\n" + "@var{imported} to find their bindings, but subsequent\n" + "references to that symbol will be as fast as references to\n" + "bindings in finite environments.\n" + "In typical use, @var{local} will be a finite environment, and\n" + "@var{imported} will be an import environment") +#define FUNC_NAME s_scm_make_eval_environment +{ + SCM env; + struct eval_environment *body; + + SCM_ASSERT (SCM_ENVIRONMENT_P (local), local, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (SCM_ENVIRONMENT_P (imported), imported, SCM_ARG2, FUNC_NAME); + + body = scm_gc_malloc (sizeof (struct eval_environment), "eval environment"); + + core_environments_preinit (&body->base); + body->obarray = SCM_BOOL_F; + body->imported = SCM_BOOL_F; + body->imported_observer = SCM_BOOL_F; + body->local = SCM_BOOL_F; + body->local_observer = SCM_BOOL_F; + + env = scm_make_environment (body); + + core_environments_init (&body->base, &eval_environment_funcs); + body->obarray = scm_c_make_hash_table (DEFAULT_OBARRAY_SIZE); + body->imported = imported; + body->imported_observer + = SCM_ENVIRONMENT_OBSERVE (imported, eval_environment_observer, env, 1); + body->local = local; + body->local_observer + = SCM_ENVIRONMENT_OBSERVE (local, eval_environment_observer, env, 1); + + return env; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_eval_environment_p, "eval-environment?", 1, 0, 0, + (SCM object), + "Return @code{#t} if object is an eval environment, or @code{#f}\n" + "otherwise.") +#define FUNC_NAME s_scm_eval_environment_p +{ + return scm_from_bool (SCM_EVAL_ENVIRONMENT_P (object)); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_eval_environment_local, "eval-environment-local", 1, 0, 0, + (SCM env), + "Return the local environment of eval environment @var{env}.") +#define FUNC_NAME s_scm_eval_environment_local +{ + SCM_ASSERT (SCM_EVAL_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return EVAL_ENVIRONMENT (env)->local; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_eval_environment_set_local_x, "eval-environment-set-local!", 2, 0, 0, + (SCM env, SCM local), + "Change @var{env}'s local environment to @var{local}.") +#define FUNC_NAME s_scm_eval_environment_set_local_x +{ + struct eval_environment *body; + + SCM_ASSERT (SCM_EVAL_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (SCM_ENVIRONMENT_P (local), local, SCM_ARG2, FUNC_NAME); + + body = EVAL_ENVIRONMENT (env); + + obarray_remove_all (body->obarray); + SCM_ENVIRONMENT_UNOBSERVE (body->local, body->local_observer); + + body->local = local; + body->local_observer + = SCM_ENVIRONMENT_OBSERVE (local, eval_environment_observer, env, 1); + + core_environments_broadcast (env); + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_eval_environment_imported, "eval-environment-imported", 1, 0, 0, + (SCM env), + "Return the imported environment of eval environment @var{env}.") +#define FUNC_NAME s_scm_eval_environment_imported +{ + SCM_ASSERT (SCM_EVAL_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return EVAL_ENVIRONMENT (env)->imported; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_eval_environment_set_imported_x, "eval-environment-set-imported!", 2, 0, 0, + (SCM env, SCM imported), + "Change @var{env}'s imported environment to @var{imported}.") +#define FUNC_NAME s_scm_eval_environment_set_imported_x +{ + struct eval_environment *body; + + SCM_ASSERT (SCM_EVAL_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (SCM_ENVIRONMENT_P (imported), imported, SCM_ARG2, FUNC_NAME); + + body = EVAL_ENVIRONMENT (env); + + obarray_remove_all (body->obarray); + SCM_ENVIRONMENT_UNOBSERVE (body->imported, body->imported_observer); + + body->imported = imported; + body->imported_observer + = SCM_ENVIRONMENT_OBSERVE (imported, eval_environment_observer, env, 1); + + core_environments_broadcast (env); + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + + +/* import environments + * + * An import environment combines the bindings of a set of argument + * environments, and checks for naming clashes. + * + * Implementation: The import environment does no caching at all. For every + * access, the list of imported environments is scanned. + */ + + +struct import_environment { + struct core_environments_base base; + + SCM imports; + SCM import_observers; + + SCM conflict_proc; +}; + + +#define IMPORT_ENVIRONMENT(env) \ + ((struct import_environment *) SCM_CELL_WORD_1 (env)) + + + +/* Lookup will report one of the following distinct results: + * a) if only environment binds the symbol. + * b) (env-1 env-2 ...) for conflicting bindings in env-1, ... + * c) SCM_UNDEFINED if there is no binding for the symbol. + */ +static SCM +import_environment_lookup (SCM env, SCM sym) +{ + SCM imports = IMPORT_ENVIRONMENT (env)->imports; + SCM result = SCM_UNDEFINED; + SCM l; + + for (l = imports; !scm_is_null (l); l = SCM_CDR (l)) + { + SCM imported = SCM_CAR (l); + + if (SCM_ENVIRONMENT_BOUND_P (imported, sym)) + { + if (SCM_UNBNDP (result)) + result = imported; + else if (scm_is_pair (result)) + result = scm_cons (imported, result); + else + result = scm_cons2 (imported, result, SCM_EOL); + } + } + + if (scm_is_pair (result)) + return scm_reverse (result); + else + return result; +} + + +static SCM +import_environment_conflict (SCM env, SCM sym, SCM imports) +{ + SCM conflict_proc = IMPORT_ENVIRONMENT (env)->conflict_proc; + SCM args = scm_cons2 (env, sym, scm_cons (imports, SCM_EOL)); + + return scm_apply_0 (conflict_proc, args); +} + + +static SCM +import_environment_ref (SCM env, SCM sym) +#define FUNC_NAME "import_environment_ref" +{ + SCM owner = import_environment_lookup (env, sym); + + if (SCM_UNBNDP (owner)) + { + return SCM_UNDEFINED; + } + else if (scm_is_pair (owner)) + { + SCM resolve = import_environment_conflict (env, sym, owner); + + if (SCM_ENVIRONMENT_P (resolve)) + return SCM_ENVIRONMENT_REF (resolve, sym); + else + return SCM_UNSPECIFIED; + } + else + { + return SCM_ENVIRONMENT_REF (owner, sym); + } +} +#undef FUNC_NAME + + +static SCM +import_environment_folder (SCM extended_data, SCM symbol, SCM value, SCM tail) +#define FUNC_NAME "import_environment_fold" +{ + SCM import_env = SCM_CAR (extended_data); + SCM imported_env = SCM_CADR (extended_data); + SCM owner = import_environment_lookup (import_env, symbol); + SCM proc_as_nr = SCM_CADDR (extended_data); + unsigned long int proc_as_ul = scm_to_ulong (proc_as_nr); + scm_environment_folder proc = (scm_environment_folder) proc_as_ul; + SCM data = SCM_CDDDR (extended_data); + + if (scm_is_pair (owner) && scm_is_eq (SCM_CAR (owner), imported_env)) + owner = import_environment_conflict (import_env, symbol, owner); + + if (SCM_ENVIRONMENT_P (owner)) + return (*proc) (data, symbol, value, tail); + else /* unresolved conflict */ + return (*proc) (data, symbol, SCM_UNSPECIFIED, tail); +} +#undef FUNC_NAME + + +static SCM +import_environment_fold (SCM env, scm_environment_folder proc, SCM data, SCM init) +{ + SCM proc_as_nr = scm_from_ulong ((unsigned long) proc); + SCM result = init; + SCM l; + + for (l = IMPORT_ENVIRONMENT (env)->imports; !scm_is_null (l); l = SCM_CDR (l)) + { + SCM imported_env = SCM_CAR (l); + SCM extended_data = scm_cons (env, scm_cons2 (imported_env, proc_as_nr, data)); + + result = scm_c_environment_fold (imported_env, import_environment_folder, extended_data, result); + } + + return result; +} + + +static SCM +import_environment_define (SCM env SCM_UNUSED, + SCM sym SCM_UNUSED, + SCM val SCM_UNUSED) +#define FUNC_NAME "import_environment_define" +{ + return SCM_ENVIRONMENT_BINDING_IMMUTABLE; +} +#undef FUNC_NAME + + +static SCM +import_environment_undefine (SCM env SCM_UNUSED, + SCM sym SCM_UNUSED) +#define FUNC_NAME "import_environment_undefine" +{ + return SCM_ENVIRONMENT_BINDING_IMMUTABLE; +} +#undef FUNC_NAME + + +static SCM +import_environment_set_x (SCM env, SCM sym, SCM val) +#define FUNC_NAME "import_environment_set_x" +{ + SCM owner = import_environment_lookup (env, sym); + + if (SCM_UNBNDP (owner)) + { + return SCM_UNDEFINED; + } + else if (scm_is_pair (owner)) + { + SCM resolve = import_environment_conflict (env, sym, owner); + + if (SCM_ENVIRONMENT_P (resolve)) + return SCM_ENVIRONMENT_SET (resolve, sym, val); + else + return SCM_ENVIRONMENT_LOCATION_IMMUTABLE; + } + else + { + return SCM_ENVIRONMENT_SET (owner, sym, val); + } +} +#undef FUNC_NAME + + +static SCM +import_environment_cell (SCM env, SCM sym, int for_write) +#define FUNC_NAME "import_environment_cell" +{ + SCM owner = import_environment_lookup (env, sym); + + if (SCM_UNBNDP (owner)) + { + return SCM_UNDEFINED; + } + else if (scm_is_pair (owner)) + { + SCM resolve = import_environment_conflict (env, sym, owner); + + if (SCM_ENVIRONMENT_P (resolve)) + return SCM_ENVIRONMENT_CELL (resolve, sym, for_write); + else + return SCM_ENVIRONMENT_LOCATION_NO_CELL; + } + else + { + return SCM_ENVIRONMENT_CELL (owner, sym, for_write); + } +} +#undef FUNC_NAME + + +static SCM +import_environment_mark (SCM env) +{ + scm_gc_mark (IMPORT_ENVIRONMENT (env)->imports); + scm_gc_mark (IMPORT_ENVIRONMENT (env)->import_observers); + scm_gc_mark (IMPORT_ENVIRONMENT (env)->conflict_proc); + return core_environments_mark (env); +} + + +static void +import_environment_free (SCM env) +{ + core_environments_finalize (env); + scm_gc_free (IMPORT_ENVIRONMENT (env), sizeof (struct import_environment), + "import environment"); +} + + +static int +import_environment_print (SCM type, SCM port, + scm_print_state *pstate SCM_UNUSED) +{ + SCM address = scm_from_size_t (SCM_UNPACK (type)); + SCM base16 = scm_number_to_string (address, scm_from_int (16)); + + scm_puts ("#", port); + + return 1; +} + + +static struct scm_environment_funcs import_environment_funcs = { + import_environment_ref, + import_environment_fold, + import_environment_define, + import_environment_undefine, + import_environment_set_x, + import_environment_cell, + core_environments_observe, + core_environments_unobserve, + import_environment_mark, + import_environment_free, + import_environment_print +}; + + +void *scm_type_import_environment = &import_environment_funcs; + + +static void +import_environment_observer (SCM caller SCM_UNUSED, SCM import_env) +{ + core_environments_broadcast (import_env); +} + + +SCM_DEFINE (scm_make_import_environment, "make-import-environment", 2, 0, 0, + (SCM imports, SCM conflict_proc), + "Return a new environment @var{imp} whose bindings are the union\n" + "of the bindings from the environments in @var{imports};\n" + "@var{imports} must be a list of environments. That is,\n" + "@var{imp} binds a symbol to a location when some element of\n" + "@var{imports} does.\n" + "If two different elements of @var{imports} have a binding for\n" + "the same symbol, the @var{conflict-proc} is called with the\n" + "following parameters: the import environment, the symbol and\n" + "the list of the imported environments that bind the symbol.\n" + "If the @var{conflict-proc} returns an environment @var{env},\n" + "the conflict is considered as resolved and the binding from\n" + "@var{env} is used. If the @var{conflict-proc} returns some\n" + "non-environment object, the conflict is considered unresolved\n" + "and the symbol is treated as unspecified in the import\n" + "environment.\n" + "The checking for conflicts may be performed lazily, i. e. at\n" + "the moment when a value or binding for a certain symbol is\n" + "requested instead of the moment when the environment is\n" + "created or the bindings of the imports change.\n" + "All bindings in @var{imp} are immutable. If you apply\n" + "@code{environment-define} or @code{environment-undefine} to\n" + "@var{imp}, Guile will signal an\n" + " @code{environment:immutable-binding} error. However,\n" + "notice that the set of bindings in @var{imp} may still change,\n" + "if one of its imported environments changes.") +#define FUNC_NAME s_scm_make_import_environment +{ + size_t size = sizeof (struct import_environment); + struct import_environment *body = scm_gc_malloc (size, "import environment"); + SCM env; + + core_environments_preinit (&body->base); + body->imports = SCM_BOOL_F; + body->import_observers = SCM_BOOL_F; + body->conflict_proc = SCM_BOOL_F; + + env = scm_make_environment (body); + + core_environments_init (&body->base, &import_environment_funcs); + body->imports = SCM_EOL; + body->import_observers = SCM_EOL; + body->conflict_proc = conflict_proc; + + scm_import_environment_set_imports_x (env, imports); + + return env; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_import_environment_p, "import-environment?", 1, 0, 0, + (SCM object), + "Return @code{#t} if object is an import environment, or\n" + "@code{#f} otherwise.") +#define FUNC_NAME s_scm_import_environment_p +{ + return scm_from_bool (SCM_IMPORT_ENVIRONMENT_P (object)); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_import_environment_imports, "import-environment-imports", 1, 0, 0, + (SCM env), + "Return the list of environments imported by the import\n" + "environment @var{env}.") +#define FUNC_NAME s_scm_import_environment_imports +{ + SCM_ASSERT (SCM_IMPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return IMPORT_ENVIRONMENT (env)->imports; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_import_environment_set_imports_x, "import-environment-set-imports!", 2, 0, 0, + (SCM env, SCM imports), + "Change @var{env}'s list of imported environments to\n" + "@var{imports}, and check for conflicts.") +#define FUNC_NAME s_scm_import_environment_set_imports_x +{ + struct import_environment *body = IMPORT_ENVIRONMENT (env); + SCM import_observers = SCM_EOL; + SCM l; + + SCM_ASSERT (SCM_IMPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + for (l = imports; scm_is_pair (l); l = SCM_CDR (l)) + { + SCM obj = SCM_CAR (l); + SCM_ASSERT (SCM_ENVIRONMENT_P (obj), imports, SCM_ARG2, FUNC_NAME); + } + SCM_ASSERT (scm_is_null (l), imports, SCM_ARG2, FUNC_NAME); + + for (l = body->import_observers; !scm_is_null (l); l = SCM_CDR (l)) + { + SCM obs = SCM_CAR (l); + SCM_ENVIRONMENT_UNOBSERVE (env, obs); + } + + for (l = imports; !scm_is_null (l); l = SCM_CDR (l)) + { + SCM imp = SCM_CAR (l); + SCM obs = SCM_ENVIRONMENT_OBSERVE (imp, import_environment_observer, env, 1); + import_observers = scm_cons (obs, import_observers); + } + + body->imports = imports; + body->import_observers = import_observers; + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + + +/* export environments + * + * An export environment restricts an environment to a specified set of + * bindings. + * + * Implementation: The export environment does no caching at all. For every + * access, the signature is scanned. The signature that is stored internally + * is an alist of pairs (symbol . (mutability)). + */ + + +struct export_environment { + struct core_environments_base base; + + SCM private; + SCM private_observer; + + SCM signature; +}; + + +#define EXPORT_ENVIRONMENT(env) \ + ((struct export_environment *) SCM_CELL_WORD_1 (env)) + + +SCM_SYMBOL (symbol_immutable_location, "immutable-location"); +SCM_SYMBOL (symbol_mutable_location, "mutable-location"); + + + +static SCM +export_environment_ref (SCM env, SCM sym) +#define FUNC_NAME "export_environment_ref" +{ + struct export_environment *body = EXPORT_ENVIRONMENT (env); + SCM entry = scm_assq (sym, body->signature); + + if (scm_is_false (entry)) + return SCM_UNDEFINED; + else + return SCM_ENVIRONMENT_REF (body->private, sym); +} +#undef FUNC_NAME + + +static SCM +export_environment_fold (SCM env, scm_environment_folder proc, SCM data, SCM init) +{ + struct export_environment *body = EXPORT_ENVIRONMENT (env); + SCM result = init; + SCM l; + + for (l = body->signature; !scm_is_null (l); l = SCM_CDR (l)) + { + SCM symbol = SCM_CAR (l); + SCM value = SCM_ENVIRONMENT_REF (body->private, symbol); + if (!SCM_UNBNDP (value)) + result = (*proc) (data, symbol, value, result); + } + return result; +} + + +static SCM +export_environment_define (SCM env SCM_UNUSED, + SCM sym SCM_UNUSED, + SCM val SCM_UNUSED) +#define FUNC_NAME "export_environment_define" +{ + return SCM_ENVIRONMENT_BINDING_IMMUTABLE; +} +#undef FUNC_NAME + + +static SCM +export_environment_undefine (SCM env SCM_UNUSED, SCM sym SCM_UNUSED) +#define FUNC_NAME "export_environment_undefine" +{ + return SCM_ENVIRONMENT_BINDING_IMMUTABLE; +} +#undef FUNC_NAME + + +static SCM +export_environment_set_x (SCM env, SCM sym, SCM val) +#define FUNC_NAME "export_environment_set_x" +{ + struct export_environment *body = EXPORT_ENVIRONMENT (env); + SCM entry = scm_assq (sym, body->signature); + + if (scm_is_false (entry)) + { + return SCM_UNDEFINED; + } + else + { + if (scm_is_eq (SCM_CADR (entry), symbol_mutable_location)) + return SCM_ENVIRONMENT_SET (body->private, sym, val); + else + return SCM_ENVIRONMENT_LOCATION_IMMUTABLE; + } +} +#undef FUNC_NAME + + +static SCM +export_environment_cell (SCM env, SCM sym, int for_write) +#define FUNC_NAME "export_environment_cell" +{ + struct export_environment *body = EXPORT_ENVIRONMENT (env); + SCM entry = scm_assq (sym, body->signature); + + if (scm_is_false (entry)) + { + return SCM_UNDEFINED; + } + else + { + if (!for_write || scm_is_eq (SCM_CADR (entry), symbol_mutable_location)) + return SCM_ENVIRONMENT_CELL (body->private, sym, for_write); + else + return SCM_ENVIRONMENT_LOCATION_IMMUTABLE; + } +} +#undef FUNC_NAME + + +static SCM +export_environment_mark (SCM env) +{ + struct export_environment *body = EXPORT_ENVIRONMENT (env); + + scm_gc_mark (body->private); + scm_gc_mark (body->private_observer); + scm_gc_mark (body->signature); + + return core_environments_mark (env); +} + + +static void +export_environment_free (SCM env) +{ + core_environments_finalize (env); + scm_gc_free (EXPORT_ENVIRONMENT (env), sizeof (struct export_environment), + "export environment"); +} + + +static int +export_environment_print (SCM type, SCM port, + scm_print_state *pstate SCM_UNUSED) +{ + SCM address = scm_from_size_t (SCM_UNPACK (type)); + SCM base16 = scm_number_to_string (address, scm_from_int (16)); + + scm_puts ("#", port); + + return 1; +} + + +static struct scm_environment_funcs export_environment_funcs = { + export_environment_ref, + export_environment_fold, + export_environment_define, + export_environment_undefine, + export_environment_set_x, + export_environment_cell, + core_environments_observe, + core_environments_unobserve, + export_environment_mark, + export_environment_free, + export_environment_print +}; + + +void *scm_type_export_environment = &export_environment_funcs; + + +static void +export_environment_observer (SCM caller SCM_UNUSED, SCM export_env) +{ + core_environments_broadcast (export_env); +} + + +SCM_DEFINE (scm_make_export_environment, "make-export-environment", 2, 0, 0, + (SCM private, SCM signature), + "Return a new environment @var{exp} containing only those\n" + "bindings in private whose symbols are present in\n" + "@var{signature}. The @var{private} argument must be an\n" + "environment.\n\n" + "The environment @var{exp} binds symbol to location when\n" + "@var{env} does, and symbol is exported by @var{signature}.\n\n" + "@var{signature} is a list specifying which of the bindings in\n" + "@var{private} should be visible in @var{exp}. Each element of\n" + "@var{signature} should be a list of the form:\n" + " (symbol attribute ...)\n" + "where each attribute is one of the following:\n" + "@table @asis\n" + "@item the symbol @code{mutable-location}\n" + " @var{exp} should treat the\n" + " location bound to symbol as mutable. That is, @var{exp}\n" + " will pass calls to @code{environment-set!} or\n" + " @code{environment-cell} directly through to private.\n" + "@item the symbol @code{immutable-location}\n" + " @var{exp} should treat\n" + " the location bound to symbol as immutable. If the program\n" + " applies @code{environment-set!} to @var{exp} and symbol, or\n" + " calls @code{environment-cell} to obtain a writable value\n" + " cell, @code{environment-set!} will signal an\n" + " @code{environment:immutable-location} error. Note that, even\n" + " if an export environment treats a location as immutable, the\n" + " underlying environment may treat it as mutable, so its\n" + " value may change.\n" + "@end table\n" + "It is an error for an element of signature to specify both\n" + "@code{mutable-location} and @code{immutable-location}. If\n" + "neither is specified, @code{immutable-location} is assumed.\n\n" + "As a special case, if an element of signature is a lone\n" + "symbol @var{sym}, it is equivalent to an element of the form\n" + "@code{(sym)}.\n\n" + "All bindings in @var{exp} are immutable. If you apply\n" + "@code{environment-define} or @code{environment-undefine} to\n" + "@var{exp}, Guile will signal an\n" + "@code{environment:immutable-binding} error. However,\n" + "notice that the set of bindings in @var{exp} may still change,\n" + "if the bindings in private change.") +#define FUNC_NAME s_scm_make_export_environment +{ + size_t size; + struct export_environment *body; + SCM env; + + SCM_ASSERT (SCM_ENVIRONMENT_P (private), private, SCM_ARG1, FUNC_NAME); + + size = sizeof (struct export_environment); + body = scm_gc_malloc (size, "export environment"); + + core_environments_preinit (&body->base); + body->private = SCM_BOOL_F; + body->private_observer = SCM_BOOL_F; + body->signature = SCM_BOOL_F; + + env = scm_make_environment (body); + + core_environments_init (&body->base, &export_environment_funcs); + body->private = private; + body->private_observer + = SCM_ENVIRONMENT_OBSERVE (private, export_environment_observer, env, 1); + body->signature = SCM_EOL; + + scm_export_environment_set_signature_x (env, signature); + + return env; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_export_environment_p, "export-environment?", 1, 0, 0, + (SCM object), + "Return @code{#t} if object is an export environment, or\n" + "@code{#f} otherwise.") +#define FUNC_NAME s_scm_export_environment_p +{ + return scm_from_bool (SCM_EXPORT_ENVIRONMENT_P (object)); +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_export_environment_private, "export-environment-private", 1, 0, 0, + (SCM env), + "Return the private environment of export environment @var{env}.") +#define FUNC_NAME s_scm_export_environment_private +{ + SCM_ASSERT (SCM_EXPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return EXPORT_ENVIRONMENT (env)->private; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_export_environment_set_private_x, "export-environment-set-private!", 2, 0, 0, + (SCM env, SCM private), + "Change the private environment of export environment @var{env}.") +#define FUNC_NAME s_scm_export_environment_set_private_x +{ + struct export_environment *body; + + SCM_ASSERT (SCM_EXPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + SCM_ASSERT (SCM_ENVIRONMENT_P (private), private, SCM_ARG2, FUNC_NAME); + + body = EXPORT_ENVIRONMENT (env); + SCM_ENVIRONMENT_UNOBSERVE (private, body->private_observer); + + body->private = private; + body->private_observer + = SCM_ENVIRONMENT_OBSERVE (private, export_environment_observer, env, 1); + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + +SCM_DEFINE (scm_export_environment_signature, "export-environment-signature", 1, 0, 0, + (SCM env), + "Return the signature of export environment @var{env}.") +#define FUNC_NAME s_scm_export_environment_signature +{ + SCM_ASSERT (SCM_EXPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + + return EXPORT_ENVIRONMENT (env)->signature; +} +#undef FUNC_NAME + + +static SCM +export_environment_parse_signature (SCM signature, const char* caller) +{ + SCM result = SCM_EOL; + SCM l; + + for (l = signature; scm_is_pair (l); l = SCM_CDR (l)) + { + SCM entry = SCM_CAR (l); + + if (scm_is_symbol (entry)) + { + SCM new_entry = scm_cons2 (entry, symbol_immutable_location, SCM_EOL); + result = scm_cons (new_entry, result); + } + else + { + SCM sym; + SCM new_entry; + int immutable = 0; + int mutable = 0; + SCM mutability; + SCM l2; + + SCM_ASSERT (scm_is_pair (entry), entry, SCM_ARGn, caller); + SCM_ASSERT (scm_is_symbol (SCM_CAR (entry)), entry, SCM_ARGn, caller); + + sym = SCM_CAR (entry); + + for (l2 = SCM_CDR (entry); scm_is_pair (l2); l2 = SCM_CDR (l2)) + { + SCM attribute = SCM_CAR (l2); + if (scm_is_eq (attribute, symbol_immutable_location)) + immutable = 1; + else if (scm_is_eq (attribute, symbol_mutable_location)) + mutable = 1; + else + SCM_ASSERT (0, entry, SCM_ARGn, caller); + } + SCM_ASSERT (scm_is_null (l2), entry, SCM_ARGn, caller); + SCM_ASSERT (!mutable || !immutable, entry, SCM_ARGn, caller); + + if (!mutable && !immutable) + immutable = 1; + + mutability = mutable ? symbol_mutable_location : symbol_immutable_location; + new_entry = scm_cons2 (sym, mutability, SCM_EOL); + result = scm_cons (new_entry, result); + } + } + SCM_ASSERT (scm_is_null (l), signature, SCM_ARGn, caller); + + /* Dirk:FIXME:: Now we know that signature is syntactically correct. There + * are, however, no checks for symbols entered twice with contradicting + * mutabilities. It would be nice, to implement this test, to be able to + * call the sort functions conveniently from C. + */ + + return scm_reverse (result); +} + + +SCM_DEFINE (scm_export_environment_set_signature_x, "export-environment-set-signature!", 2, 0, 0, + (SCM env, SCM signature), + "Change the signature of export environment @var{env}.") +#define FUNC_NAME s_scm_export_environment_set_signature_x +{ + SCM parsed_sig; + + SCM_ASSERT (SCM_EXPORT_ENVIRONMENT_P (env), env, SCM_ARG1, FUNC_NAME); + parsed_sig = export_environment_parse_signature (signature, FUNC_NAME); + + EXPORT_ENVIRONMENT (env)->signature = parsed_sig; + + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + + + +void +scm_environments_prehistory () +{ + /* create environment smob */ + scm_tc16_environment = scm_make_smob_type ("environment", 0); + scm_set_smob_mark (scm_tc16_environment, environment_mark); + scm_set_smob_free (scm_tc16_environment, environment_free); + scm_set_smob_print (scm_tc16_environment, environment_print); + + /* create observer smob */ + scm_tc16_observer = scm_make_smob_type ("observer", 0); + scm_set_smob_mark (scm_tc16_observer, observer_mark); + scm_set_smob_print (scm_tc16_observer, observer_print); + + /* create system environment */ + scm_system_environment = scm_make_leaf_environment (); + scm_permanent_object (scm_system_environment); +} + + +void +scm_init_environments () +{ +#include "libguile/environments.x" +} + + +/* + Local Variables: + c-file-style: "gnu" + End: +*/