-/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008
- * 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
- */
-
-\f
-
-/* SECTION: This code is compiled once.
- */
-
-#if HAVE_CONFIG_H
-# include <config.h>
-#endif
-
-#include <alloca.h>
-
-#include "libguile/__scm.h"
-
-#include <assert.h>
-#include "libguile/_scm.h"
-#include "libguile/alist.h"
-#include "libguile/async.h"
-#include "libguile/continuations.h"
-#include "libguile/debug.h"
-#include "libguile/deprecation.h"
-#include "libguile/dynwind.h"
-#include "libguile/eq.h"
-#include "libguile/feature.h"
-#include "libguile/fluids.h"
-#include "libguile/futures.h"
-#include "libguile/goops.h"
-#include "libguile/hash.h"
-#include "libguile/hashtab.h"
-#include "libguile/lang.h"
-#include "libguile/list.h"
-#include "libguile/macros.h"
-#include "libguile/modules.h"
-#include "libguile/objects.h"
-#include "libguile/ports.h"
-#include "libguile/print.h"
-#include "libguile/procprop.h"
-#include "libguile/root.h"
-#include "libguile/smob.h"
-#include "libguile/srcprop.h"
-#include "libguile/stackchk.h"
-#include "libguile/strings.h"
-#include "libguile/threads.h"
-#include "libguile/throw.h"
-#include "libguile/validate.h"
-#include "libguile/values.h"
-#include "libguile/vectors.h"
-
-#include "libguile/eval.h"
-#include "libguile/private-options.h"
-
-\f
-
-
-static SCM unmemoize_exprs (SCM expr, SCM env);
-static SCM canonicalize_define (SCM expr);
-static SCM *scm_lookupcar1 (SCM vloc, SCM genv, int check);
-static SCM unmemoize_builtin_macro (SCM expr, SCM env);
-static void ceval_letrec_inits (SCM env, SCM init_forms, SCM **init_values_eol);
-static SCM ceval (SCM x, SCM env);
-static SCM deval (SCM x, SCM env);
-
-\f
-
-/* {Syntax Errors}
- *
- * This section defines the message strings for the syntax errors that can be
- * detected during memoization and the functions and macros that shall be
- * called by the memoizer code to signal syntax errors. */
-
-
-/* Syntax errors that can be detected during memoization: */
-
-/* Circular or improper lists do not form valid scheme expressions. If a
- * circular list or an improper list is detected in a place where a scheme
- * expression is expected, a 'Bad expression' error is signalled. */
-static const char s_bad_expression[] = "Bad expression";
-
-/* If a form is detected that holds a different number of expressions than are
- * required in that context, a 'Missing or extra expression' error is
- * signalled. */
-static const char s_expression[] = "Missing or extra expression in";
-
-/* If a form is detected that holds less expressions than are required in that
- * context, a 'Missing expression' error is signalled. */
-static const char s_missing_expression[] = "Missing expression in";
-
-/* If a form is detected that holds more expressions than are allowed in that
- * context, an 'Extra expression' error is signalled. */
-static const char s_extra_expression[] = "Extra expression in";
-
-/* The empty combination '()' is not allowed as an expression in scheme. If
- * it is detected in a place where an expression is expected, an 'Illegal
- * empty combination' error is signalled. Note: If you encounter this error
- * message, it is very likely that you intended to denote the empty list. To
- * do so, you need to quote the empty list like (quote ()) or '(). */
-static const char s_empty_combination[] = "Illegal empty combination";
-
-/* A body may hold an arbitrary number of internal defines, followed by a
- * non-empty sequence of expressions. If a body with an empty sequence of
- * expressions is detected, a 'Missing body expression' error is signalled.
- */
-static const char s_missing_body_expression[] = "Missing body expression in";
-
-/* A body may hold an arbitrary number of internal defines, followed by a
- * non-empty sequence of expressions. Each the definitions and the
- * expressions may be grouped arbitraryly with begin, but it is not allowed to
- * mix definitions and expressions. If a define form in a body mixes
- * definitions and expressions, a 'Mixed definitions and expressions' error is
- * signalled. */
-static const char s_mixed_body_forms[] = "Mixed definitions and expressions in";
-/* Definitions are only allowed on the top level and at the start of a body.
- * If a definition is detected anywhere else, a 'Bad define placement' error
- * is signalled. */
-static const char s_bad_define[] = "Bad define placement";
-
-/* Case or cond expressions must have at least one clause. If a case or cond
- * expression without any clauses is detected, a 'Missing clauses' error is
- * signalled. */
-static const char s_missing_clauses[] = "Missing clauses";
-
-/* If there is an 'else' clause in a case or a cond statement, it must be the
- * last clause. If after the 'else' case clause further clauses are detected,
- * a 'Misplaced else clause' error is signalled. */
-static const char s_misplaced_else_clause[] = "Misplaced else clause";
-
-/* If a case clause is detected that is not in the format
- * (<label(s)> <expression1> <expression2> ...)
- * a 'Bad case clause' error is signalled. */
-static const char s_bad_case_clause[] = "Bad case clause";
-
-/* If a case clause is detected where the <label(s)> element is neither a
- * proper list nor (in case of the last clause) the syntactic keyword 'else',
- * a 'Bad case labels' error is signalled. Note: If you encounter this error
- * for an else-clause which seems to be syntactically correct, check if 'else'
- * is really a syntactic keyword in that context. If 'else' is bound in the
- * local or global environment, it is not considered a syntactic keyword, but
- * will be treated as any other variable. */
-static const char s_bad_case_labels[] = "Bad case labels";
-
-/* In a case statement all labels have to be distinct. If in a case statement
- * a label occurs more than once, a 'Duplicate case label' error is
- * signalled. */
-static const char s_duplicate_case_label[] = "Duplicate case label";
-
-/* If a cond clause is detected that is not in one of the formats
- * (<test> <expression1> ...) or (else <expression1> <expression2> ...)
- * a 'Bad cond clause' error is signalled. */
-static const char s_bad_cond_clause[] = "Bad cond clause";
-
-/* If a cond clause is detected that uses the alternate '=>' form, but does
- * not hold a recipient element for the test result, a 'Missing recipient'
- * error is signalled. */
-static const char s_missing_recipient[] = "Missing recipient in";
-
-/* If in a position where a variable name is required some other object is
- * detected, a 'Bad variable' error is signalled. */
-static const char s_bad_variable[] = "Bad variable";
-
-/* Bindings for forms like 'let' and 'do' have to be given in a proper,
- * possibly empty list. If any other object is detected in a place where a
- * list of bindings was required, a 'Bad bindings' error is signalled. */
-static const char s_bad_bindings[] = "Bad bindings";
-
-/* Depending on the syntactic context, a binding has to be in the format
- * (<variable> <expression>) or (<variable> <expression1> <expression2>).
- * If anything else is detected in a place where a binding was expected, a
- * 'Bad binding' error is signalled. */
-static const char s_bad_binding[] = "Bad binding";
-
-/* Some syntactic forms don't allow variable names to appear more than once in
- * a list of bindings. If such a situation is nevertheless detected, a
- * 'Duplicate binding' error is signalled. */
-static const char s_duplicate_binding[] = "Duplicate binding";
-
-/* If the exit form of a 'do' expression is not in the format
- * (<test> <expression> ...)
- * a 'Bad exit clause' error is signalled. */
-static const char s_bad_exit_clause[] = "Bad exit clause";
-
-/* The formal function arguments of a lambda expression have to be either a
- * single symbol or a non-cyclic list. For anything else a 'Bad formals'
- * error is signalled. */
-static const char s_bad_formals[] = "Bad formals";
-
-/* If in a lambda expression something else than a symbol is detected at a
- * place where a formal function argument is required, a 'Bad formal' error is
- * signalled. */
-static const char s_bad_formal[] = "Bad formal";
-
-/* If in the arguments list of a lambda expression an argument name occurs
- * more than once, a 'Duplicate formal' error is signalled. */
-static const char s_duplicate_formal[] = "Duplicate formal";
-
-/* If the evaluation of an unquote-splicing expression gives something else
- * than a proper list, a 'Non-list result for unquote-splicing' error is
- * signalled. */
-static const char s_splicing[] = "Non-list result for unquote-splicing";
-
-/* If something else than an exact integer is detected as the argument for
- * @slot-ref and @slot-set!, a 'Bad slot number' error is signalled. */
-static const char s_bad_slot_number[] = "Bad slot number";
-
-
-/* Signal a syntax error. We distinguish between the form that caused the
- * error and the enclosing expression. The error message will print out as
- * shown in the following pattern. The file name and line number are only
- * given when they can be determined from the erroneous form or from the
- * enclosing expression.
- *
- * <filename>: In procedure memoization:
- * <filename>: In file <name>, line <nr>: <error-message> in <expression>. */
-
-SCM_SYMBOL (syntax_error_key, "syntax-error");
-
-/* The prototype is needed to indicate that the function does not return. */
-static void
-syntax_error (const char* const, const SCM, const SCM) SCM_NORETURN;
-
-static void
-syntax_error (const char* const msg, const SCM form, const SCM expr)
-{
- SCM msg_string = scm_from_locale_string (msg);
- SCM filename = SCM_BOOL_F;
- SCM linenr = SCM_BOOL_F;
- const char *format;
- SCM args;
-
- if (scm_is_pair (form))
- {
- filename = scm_source_property (form, scm_sym_filename);
- linenr = scm_source_property (form, scm_sym_line);
- }
-
- if (scm_is_false (filename) && scm_is_false (linenr) && scm_is_pair (expr))
- {
- filename = scm_source_property (expr, scm_sym_filename);
- linenr = scm_source_property (expr, scm_sym_line);
- }
-
- if (!SCM_UNBNDP (expr))
- {
- if (scm_is_true (filename))
- {
- format = "In file ~S, line ~S: ~A ~S in expression ~S.";
- args = scm_list_5 (filename, linenr, msg_string, form, expr);
- }
- else if (scm_is_true (linenr))
- {
- format = "In line ~S: ~A ~S in expression ~S.";
- args = scm_list_4 (linenr, msg_string, form, expr);
- }
- else
- {
- format = "~A ~S in expression ~S.";
- args = scm_list_3 (msg_string, form, expr);
- }
- }
- else
- {
- if (scm_is_true (filename))
- {
- format = "In file ~S, line ~S: ~A ~S.";
- args = scm_list_4 (filename, linenr, msg_string, form);
- }
- else if (scm_is_true (linenr))
- {
- format = "In line ~S: ~A ~S.";
- args = scm_list_3 (linenr, msg_string, form);
- }
- else
- {
- format = "~A ~S.";
- args = scm_list_2 (msg_string, form);
- }
- }
-
- scm_error (syntax_error_key, "memoization", format, args, SCM_BOOL_F);
-}
-
-
-/* Shortcut macros to simplify syntax error handling. */
-#define ASSERT_SYNTAX(cond, message, form) \
- { if (SCM_UNLIKELY (!(cond))) \
- syntax_error (message, form, SCM_UNDEFINED); }
-#define ASSERT_SYNTAX_2(cond, message, form, expr) \
- { if (SCM_UNLIKELY (!(cond))) \
- syntax_error (message, form, expr); }
-
-\f
-
-/* {Ilocs}
- *
- * Ilocs are memoized references to variables in local environment frames.
- * They are represented as three values: The relative offset of the
- * environment frame, the number of the binding within that frame, and a
- * boolean value indicating whether the binding is the last binding in the
- * frame.
- *
- * Frame numbers have 11 bits, relative offsets have 12 bits.
- */
-
-#define SCM_ILOC00 SCM_MAKE_ITAG8(0L, scm_tc8_iloc)
-#define SCM_IFRINC (0x00000100L)
-#define SCM_ICDR (0x00080000L)
-#define SCM_IDINC (0x00100000L)
-#define SCM_IFRAME(n) ((long)((SCM_ICDR-SCM_IFRINC)>>8) \
- & (SCM_UNPACK (n) >> 8))
-#define SCM_IDIST(n) (SCM_UNPACK (n) >> 20)
-#define SCM_ICDRP(n) (SCM_ICDR & SCM_UNPACK (n))
-#define SCM_IDSTMSK (-SCM_IDINC)
-#define SCM_IFRAMEMAX ((1<<11)-1)
-#define SCM_IDISTMAX ((1<<12)-1)
-#define SCM_MAKE_ILOC(frame_nr, binding_nr, last_p) \
- SCM_PACK ( \
- ((frame_nr) << 8) \
- + ((binding_nr) << 20) \
- + ((last_p) ? SCM_ICDR : 0) \
- + scm_tc8_iloc )
-
-void
-scm_i_print_iloc (SCM iloc, SCM port)
-{
- scm_puts ("#@", port);
- scm_intprint ((long) SCM_IFRAME (iloc), 10, port);
- scm_putc (SCM_ICDRP (iloc) ? '-' : '+', port);
- scm_intprint ((long) SCM_IDIST (iloc), 10, port);
-}
-
-#if (SCM_DEBUG_DEBUGGING_SUPPORT == 1)
-
-SCM scm_dbg_make_iloc (SCM frame, SCM binding, SCM cdrp);
-
-SCM_DEFINE (scm_dbg_make_iloc, "dbg-make-iloc", 3, 0, 0,
- (SCM frame, SCM binding, SCM cdrp),
- "Return a new iloc with frame offset @var{frame}, binding\n"
- "offset @var{binding} and the cdr flag @var{cdrp}.")
-#define FUNC_NAME s_scm_dbg_make_iloc
-{
- return SCM_MAKE_ILOC ((scm_t_bits) scm_to_unsigned_integer (frame, 0, SCM_IFRAMEMAX),
- (scm_t_bits) scm_to_unsigned_integer (binding, 0, SCM_IDISTMAX),
- scm_is_true (cdrp));
-}
-#undef FUNC_NAME
-
-SCM scm_dbg_iloc_p (SCM obj);
-
-SCM_DEFINE (scm_dbg_iloc_p, "dbg-iloc?", 1, 0, 0,
- (SCM obj),
- "Return @code{#t} if @var{obj} is an iloc.")
-#define FUNC_NAME s_scm_dbg_iloc_p
-{
- return scm_from_bool (SCM_ILOCP (obj));
-}
-#undef FUNC_NAME
-
-#endif
-
-\f
-
-/* {Evaluator byte codes (isyms)}
- */
-
-#define ISYMNUM(n) (SCM_ITAG8_DATA (n))
-
-/* This table must agree with the list of SCM_IM_ constants in tags.h */
-static const char *const isymnames[] =
-{
- "#@and",
- "#@begin",
- "#@case",
- "#@cond",
- "#@do",
- "#@if",
- "#@lambda",
- "#@let",
- "#@let*",
- "#@letrec",
- "#@or",
- "#@quote",
- "#@set!",
- "#@define",
- "#@apply",
- "#@call-with-current-continuation",
- "#@dispatch",
- "#@slot-ref",
- "#@slot-set!",
- "#@delay",
- "#@future",
- "#@call-with-values",
- "#@else",
- "#@arrow",
- "#@nil-cond",
- "#@bind"
-};
-
-void
-scm_i_print_isym (SCM isym, SCM port)
-{
- const size_t isymnum = ISYMNUM (isym);
- if (isymnum < (sizeof isymnames / sizeof (char *)))
- scm_puts (isymnames[isymnum], port);
- else
- scm_ipruk ("isym", isym, port);
-}
-
-\f
-
-/* The function lookup_symbol is used during memoization: Lookup the symbol in
- * the environment. If there is no binding for the symbol, SCM_UNDEFINED is
- * returned. If the symbol is a global variable, the variable object to which
- * the symbol is bound is returned. Finally, if the symbol is a local
- * variable the corresponding iloc object is returned. */
-
-/* A helper function for lookup_symbol: Try to find the symbol in the top
- * level environment frame. The function returns SCM_UNDEFINED if the symbol
- * is unbound and it returns a variable object if the symbol is a global
- * variable. */
-static SCM
-lookup_global_symbol (const SCM symbol, const SCM top_level)
-{
- const SCM variable = scm_sym2var (symbol, top_level, SCM_BOOL_F);
- if (scm_is_false (variable))
- return SCM_UNDEFINED;
- else
- return variable;
-}
-
-static SCM
-lookup_symbol (const SCM symbol, const SCM env)
-{
- SCM frame_idx;
- unsigned int frame_nr;
-
- for (frame_idx = env, frame_nr = 0;
- !scm_is_null (frame_idx);
- frame_idx = SCM_CDR (frame_idx), ++frame_nr)
- {
- const SCM frame = SCM_CAR (frame_idx);
- if (scm_is_pair (frame))
- {
- /* frame holds a local environment frame */
- SCM symbol_idx;
- unsigned int symbol_nr;
-
- for (symbol_idx = SCM_CAR (frame), symbol_nr = 0;
- scm_is_pair (symbol_idx);
- symbol_idx = SCM_CDR (symbol_idx), ++symbol_nr)
- {
- if (scm_is_eq (SCM_CAR (symbol_idx), symbol))
- /* found the symbol, therefore return the iloc */
- return SCM_MAKE_ILOC (frame_nr, symbol_nr, 0);
- }
- if (scm_is_eq (symbol_idx, symbol))
- /* found the symbol as the last element of the current frame */
- return SCM_MAKE_ILOC (frame_nr, symbol_nr, 1);
- }
- else
- {
- /* no more local environment frames */
- return lookup_global_symbol (symbol, frame);
- }
- }
-
- return lookup_global_symbol (symbol, SCM_BOOL_F);
-}
-
-
-/* Return true if the symbol is - from the point of view of a macro
- * transformer - a literal in the sense specified in chapter "pattern
- * language" of R5RS. In the code below, however, we don't match the
- * definition of R5RS exactly: It returns true if the identifier has no
- * binding or if it is a syntactic keyword. */
-static int
-literal_p (const SCM symbol, const SCM env)
-{
- const SCM variable = lookup_symbol (symbol, env);
- if (SCM_UNBNDP (variable))
- return 1;
- if (SCM_VARIABLEP (variable) && SCM_MACROP (SCM_VARIABLE_REF (variable)))
- return 1;
- else
- return 0;
-}
-
-
-/* Return true if the expression is self-quoting in the memoized code. Thus,
- * some other objects (like e. g. vectors) are reported as self-quoting, which
- * according to R5RS would need to be quoted. */
-static int
-is_self_quoting_p (const SCM expr)
-{
- if (scm_is_pair (expr))
- return 0;
- else if (scm_is_symbol (expr))
- return 0;
- else if (scm_is_null (expr))
- return 0;
- else return 1;
-}
-
-
-SCM_SYMBOL (sym_three_question_marks, "???");
-
-static SCM
-unmemoize_expression (const SCM expr, const SCM env)
-{
- if (SCM_ILOCP (expr))
- {
- SCM frame_idx;
- unsigned long int frame_nr;
- SCM symbol_idx;
- unsigned long int symbol_nr;
-
- for (frame_idx = env, frame_nr = SCM_IFRAME (expr);
- frame_nr != 0;
- frame_idx = SCM_CDR (frame_idx), --frame_nr)
- ;
- for (symbol_idx = SCM_CAAR (frame_idx), symbol_nr = SCM_IDIST (expr);
- symbol_nr != 0;
- symbol_idx = SCM_CDR (symbol_idx), --symbol_nr)
- ;
- return SCM_ICDRP (expr) ? symbol_idx : SCM_CAR (symbol_idx);
- }
- else if (SCM_VARIABLEP (expr))
- {
- const SCM sym = scm_module_reverse_lookup (scm_env_module (env), expr);
- return scm_is_true (sym) ? sym : sym_three_question_marks;
- }
- else if (scm_is_simple_vector (expr))
- {
- return scm_list_2 (scm_sym_quote, expr);
- }
- else if (!scm_is_pair (expr))
- {
- return expr;
- }
- else if (SCM_ISYMP (SCM_CAR (expr)))
- {
- return unmemoize_builtin_macro (expr, env);
- }
- else
- {
- return unmemoize_exprs (expr, env);
- }
-}
-
-
-static SCM
-unmemoize_exprs (const SCM exprs, const SCM env)
-{
- SCM r_result = SCM_EOL;
- SCM expr_idx = exprs;
- SCM um_expr;
-
- /* Note that due to the current lazy memoizer we may find partially memoized
- * code during execution. In such code we have to expect improper lists of
- * expressions: On the one hand, for such code syntax checks have not yet
- * fully been performed, on the other hand, there may be even legal code
- * like '(a . b) appear as an improper list of expressions as long as the
- * quote expression is still in its unmemoized form. For this reason, the
- * following code handles improper lists of expressions until memoization
- * and execution have been completely separated. */
- for (; scm_is_pair (expr_idx); expr_idx = SCM_CDR (expr_idx))
- {
- const SCM expr = SCM_CAR (expr_idx);
-
- /* In partially memoized code, lists of expressions that stem from a
- * body form may start with an ISYM if the body itself has not yet been
- * memoized. This isym is just an internal marker to indicate that the
- * body still needs to be memoized. An isym may occur at the very
- * beginning of the body or after one or more comment strings. It is
- * dropped during unmemoization. */
- if (!SCM_ISYMP (expr))
- {
- um_expr = unmemoize_expression (expr, env);
- r_result = scm_cons (um_expr, r_result);
- }
- }
- um_expr = unmemoize_expression (expr_idx, env);
- if (!scm_is_null (r_result))
- {
- const SCM result = scm_reverse_x (r_result, SCM_UNDEFINED);
- SCM_SETCDR (r_result, um_expr);
- return result;
- }
- else
- {
- return um_expr;
- }
-}
-
-
-/* Rewrite the body (which is given as the list of expressions forming the
- * body) into its internal form. The internal form of a body (<expr> ...) is
- * just the body itself, but prefixed with an ISYM that denotes to what kind
- * of outer construct this body belongs: (<ISYM> <expr> ...). A lambda body
- * starts with SCM_IM_LAMBDA, for example, a body of a let starts with
- * SCM_IM_LET, etc.
- *
- * It is assumed that the calling expression has already made sure that the
- * body is a proper list. */
-static SCM
-m_body (SCM op, SCM exprs)
-{
- /* Don't add another ISYM if one is present already. */
- if (SCM_ISYMP (SCM_CAR (exprs)))
- return exprs;
- else
- return scm_cons (op, exprs);
-}
-
-
-/* The function m_expand_body memoizes a proper list of expressions forming a
- * body. This function takes care of dealing with internal defines and
- * transforming them into an equivalent letrec expression. The list of
- * expressions is rewritten in place. */
-
-/* This is a helper function for m_expand_body. If the argument expression is
- * a symbol that denotes a syntactic keyword, the corresponding macro object
- * is returned, in all other cases the function returns SCM_UNDEFINED. */
-static SCM
-try_macro_lookup (const SCM expr, const SCM env)
-{
- if (scm_is_symbol (expr))
- {
- const SCM variable = lookup_symbol (expr, env);
- if (SCM_VARIABLEP (variable))
- {
- const SCM value = SCM_VARIABLE_REF (variable);
- if (SCM_MACROP (value))
- return value;
- }
- }
-
- return SCM_UNDEFINED;
-}
-
-/* This is a helper function for m_expand_body. It expands user macros,
- * because for the correct translation of a body we need to know whether they
- * expand to a definition. */
-static SCM
-expand_user_macros (SCM expr, const SCM env)
-{
- while (scm_is_pair (expr))
- {
- const SCM car_expr = SCM_CAR (expr);
- const SCM new_car = expand_user_macros (car_expr, env);
- const SCM value = try_macro_lookup (new_car, env);
-
- if (SCM_MACROP (value) && SCM_MACRO_TYPE (value) == 2)
- {
- /* User macros transform code into code. */
- expr = scm_call_2 (SCM_MACRO_CODE (value), expr, env);
- /* We need to reiterate on the transformed code. */
- }
- else
- {
- /* No user macro: return. */
- SCM_SETCAR (expr, new_car);
- return expr;
- }
- }
-
- return expr;
-}
-
-/* This is a helper function for m_expand_body. It determines if a given form
- * represents an application of a given built-in macro. The built-in macro to
- * check for is identified by its syntactic keyword. The form is an
- * application of the given macro if looking up the car of the form in the
- * given environment actually returns the built-in macro. */
-static int
-is_system_macro_p (const SCM syntactic_keyword, const SCM form, const SCM env)
-{
- if (scm_is_pair (form))
- {
- const SCM car_form = SCM_CAR (form);
- const SCM value = try_macro_lookup (car_form, env);
- if (SCM_BUILTIN_MACRO_P (value))
- {
- const SCM macro_name = scm_macro_name (value);
- return scm_is_eq (macro_name, syntactic_keyword);
- }
- }
-
- return 0;
-}
-
-static void
-m_expand_body (const SCM forms, const SCM env)
-{
- /* The first body form can be skipped since it is known to be the ISYM that
- * was prepended to the body by m_body. */
- SCM cdr_forms = SCM_CDR (forms);
- SCM form_idx = cdr_forms;
- SCM definitions = SCM_EOL;
- SCM sequence = SCM_EOL;
-
- /* According to R5RS, the list of body forms consists of two parts: a number
- * (maybe zero) of definitions, followed by a non-empty sequence of
- * expressions. Each the definitions and the expressions may be grouped
- * arbitrarily with begin, but it is not allowed to mix definitions and
- * expressions. The task of the following loop therefore is to split the
- * list of body forms into the list of definitions and the sequence of
- * expressions. */
- while (!scm_is_null (form_idx))
- {
- const SCM form = SCM_CAR (form_idx);
- const SCM new_form = expand_user_macros (form, env);
- if (is_system_macro_p (scm_sym_define, new_form, env))
- {
- definitions = scm_cons (new_form, definitions);
- form_idx = SCM_CDR (form_idx);
- }
- else if (is_system_macro_p (scm_sym_begin, new_form, env))
- {
- /* We have encountered a group of forms. This has to be either a
- * (possibly empty) group of (possibly further grouped) definitions,
- * or a non-empty group of (possibly further grouped)
- * expressions. */
- const SCM grouped_forms = SCM_CDR (new_form);
- unsigned int found_definition = 0;
- unsigned int found_expression = 0;
- SCM grouped_form_idx = grouped_forms;
- while (!found_expression && !scm_is_null (grouped_form_idx))
- {
- const SCM inner_form = SCM_CAR (grouped_form_idx);
- const SCM new_inner_form = expand_user_macros (inner_form, env);
- if (is_system_macro_p (scm_sym_define, new_inner_form, env))
- {
- found_definition = 1;
- definitions = scm_cons (new_inner_form, definitions);
- grouped_form_idx = SCM_CDR (grouped_form_idx);
- }
- else if (is_system_macro_p (scm_sym_begin, new_inner_form, env))
- {
- const SCM inner_group = SCM_CDR (new_inner_form);
- grouped_form_idx
- = scm_append (scm_list_2 (inner_group,
- SCM_CDR (grouped_form_idx)));
- }
- else
- {
- /* The group marks the start of the expressions of the body.
- * We have to make sure that within the same group we have
- * not encountered a definition before. */
- ASSERT_SYNTAX (!found_definition, s_mixed_body_forms, form);
- found_expression = 1;
- grouped_form_idx = SCM_EOL;
- }
- }
-
- /* We have finished processing the group. If we have not yet
- * encountered an expression we continue processing the forms of the
- * body to collect further definition forms. Otherwise, the group
- * marks the start of the sequence of expressions of the body. */
- if (!found_expression)
- {
- form_idx = SCM_CDR (form_idx);
- }
- else
- {
- sequence = form_idx;
- form_idx = SCM_EOL;
- }
- }
- else
- {
- /* We have detected a form which is no definition. This marks the
- * start of the sequence of expressions of the body. */
- sequence = form_idx;
- form_idx = SCM_EOL;
- }
- }
-
- /* FIXME: forms does not hold information about the file location. */
- ASSERT_SYNTAX (scm_is_pair (sequence), s_missing_body_expression, cdr_forms);
-
- if (!scm_is_null (definitions))
- {
- SCM definition_idx;
- SCM letrec_tail;
- SCM letrec_expression;
- SCM new_letrec_expression;
-
- SCM bindings = SCM_EOL;
- for (definition_idx = definitions;
- !scm_is_null (definition_idx);
- definition_idx = SCM_CDR (definition_idx))
- {
- const SCM definition = SCM_CAR (definition_idx);
- const SCM canonical_definition = canonicalize_define (definition);
- const SCM binding = SCM_CDR (canonical_definition);
- bindings = scm_cons (binding, bindings);
- };
-
- letrec_tail = scm_cons (bindings, sequence);
- /* FIXME: forms does not hold information about the file location. */
- letrec_expression = scm_cons_source (forms, scm_sym_letrec, letrec_tail);
- new_letrec_expression = scm_m_letrec (letrec_expression, env);
- SCM_SETCAR (forms, new_letrec_expression);
- SCM_SETCDR (forms, SCM_EOL);
- }
- else
- {
- SCM_SETCAR (forms, SCM_CAR (sequence));
- SCM_SETCDR (forms, SCM_CDR (sequence));
- }
-}
-
-static SCM
-macroexp (SCM x, SCM env)
-{
- SCM res, proc, orig_sym;
-
- /* Don't bother to produce error messages here. We get them when we
- eventually execute the code for real. */
-
- macro_tail:
- orig_sym = SCM_CAR (x);
- if (!scm_is_symbol (orig_sym))
- return x;
-
- {
- SCM *proc_ptr = scm_lookupcar1 (x, env, 0);
- if (proc_ptr == NULL)
- {
- /* We have lost the race. */
- goto macro_tail;
- }
- proc = *proc_ptr;
- }
-
- /* Only handle memoizing macros. `Acros' and `macros' are really
- special forms and should not be evaluated here. */
-
- if (!SCM_MACROP (proc)
- || (SCM_MACRO_TYPE (proc) != 2 && !SCM_BUILTIN_MACRO_P (proc)))
- return x;
-
- SCM_SETCAR (x, orig_sym); /* Undo memoizing effect of lookupcar */
- res = scm_call_2 (SCM_MACRO_CODE (proc), x, env);
-
- if (scm_ilength (res) <= 0)
- /* Result of expansion is not a list. */
- return (scm_list_2 (SCM_IM_BEGIN, res));
- else
- {
- /* njrev: Several queries here: (1) I don't see how it can be
- correct that the SCM_SETCAR 2 lines below this comment needs
- protection, but the SCM_SETCAR 6 lines above does not, so
- something here is probably wrong. (2) macroexp() is now only
- used in one place - scm_m_generalized_set_x - whereas all other
- macro expansion happens through expand_user_macros. Therefore
- (2.1) perhaps macroexp() could be eliminated completely now?
- (2.2) Does expand_user_macros need any critical section
- protection? */
-
- SCM_CRITICAL_SECTION_START;
- SCM_SETCAR (x, SCM_CAR (res));
- SCM_SETCDR (x, SCM_CDR (res));
- SCM_CRITICAL_SECTION_END;
-
- goto macro_tail;
- }
-}
-
-/* Start of the memoizers for the standard R5RS builtin macros. */
-
-
-SCM_SYNTAX (s_and, "and", scm_i_makbimacro, scm_m_and);
-SCM_GLOBAL_SYMBOL (scm_sym_and, s_and);
-
-SCM
-scm_m_and (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const long length = scm_ilength (cdr_expr);
-
- ASSERT_SYNTAX (length >= 0, s_bad_expression, expr);
-
- if (length == 0)
- {
- /* Special case: (and) is replaced by #t. */
- return SCM_BOOL_T;
- }
- else
- {
- SCM_SETCAR (expr, SCM_IM_AND);
- return expr;
- }
-}
-
-static SCM
-unmemoize_and (const SCM expr, const SCM env)
-{
- return scm_cons (scm_sym_and, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-SCM_SYNTAX (s_begin, "begin", scm_i_makbimacro, scm_m_begin);
-SCM_GLOBAL_SYMBOL (scm_sym_begin, s_begin);
-
-SCM
-scm_m_begin (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- /* Dirk:FIXME:: An empty begin clause is not generally allowed by R5RS.
- * That means, there should be a distinction between uses of begin where an
- * empty clause is OK and where it is not. */
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
-
- SCM_SETCAR (expr, SCM_IM_BEGIN);
- return expr;
-}
-
-static SCM
-unmemoize_begin (const SCM expr, const SCM env)
-{
- return scm_cons (scm_sym_begin, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-SCM_SYNTAX (s_case, "case", scm_i_makbimacro, scm_m_case);
-SCM_GLOBAL_SYMBOL (scm_sym_case, s_case);
-SCM_GLOBAL_SYMBOL (scm_sym_else, "else");
-
-SCM
-scm_m_case (SCM expr, SCM env)
-{
- SCM clauses;
- SCM all_labels = SCM_EOL;
-
- /* Check, whether 'else is a literal, i. e. not bound to a value. */
- const int else_literal_p = literal_p (scm_sym_else, env);
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_clauses, expr);
-
- clauses = SCM_CDR (cdr_expr);
- while (!scm_is_null (clauses))
- {
- SCM labels;
-
- const SCM clause = SCM_CAR (clauses);
- ASSERT_SYNTAX_2 (scm_ilength (clause) >= 2,
- s_bad_case_clause, clause, expr);
-
- labels = SCM_CAR (clause);
- if (scm_is_pair (labels))
- {
- ASSERT_SYNTAX_2 (scm_ilength (labels) >= 0,
- s_bad_case_labels, labels, expr);
- all_labels = scm_append (scm_list_2 (labels, all_labels));
- }
- else if (scm_is_null (labels))
- {
- /* The list of labels is empty. According to R5RS this is allowed.
- * It means that the sequence of expressions will never be executed.
- * Therefore, as an optimization, we could remove the whole
- * clause. */
- }
- else
- {
- ASSERT_SYNTAX_2 (scm_is_eq (labels, scm_sym_else) && else_literal_p,
- s_bad_case_labels, labels, expr);
- ASSERT_SYNTAX_2 (scm_is_null (SCM_CDR (clauses)),
- s_misplaced_else_clause, clause, expr);
- }
-
- /* build the new clause */
- if (scm_is_eq (labels, scm_sym_else))
- SCM_SETCAR (clause, SCM_IM_ELSE);
-
- clauses = SCM_CDR (clauses);
- }
-
- /* Check whether all case labels are distinct. */
- for (; !scm_is_null (all_labels); all_labels = SCM_CDR (all_labels))
- {
- const SCM label = SCM_CAR (all_labels);
- ASSERT_SYNTAX_2 (scm_is_false (scm_c_memq (label, SCM_CDR (all_labels))),
- s_duplicate_case_label, label, expr);
- }
-
- SCM_SETCAR (expr, SCM_IM_CASE);
- return expr;
-}
-
-static SCM
-unmemoize_case (const SCM expr, const SCM env)
-{
- const SCM um_key_expr = unmemoize_expression (SCM_CADR (expr), env);
- SCM um_clauses = SCM_EOL;
- SCM clause_idx;
-
- for (clause_idx = SCM_CDDR (expr);
- !scm_is_null (clause_idx);
- clause_idx = SCM_CDR (clause_idx))
- {
- const SCM clause = SCM_CAR (clause_idx);
- const SCM labels = SCM_CAR (clause);
- const SCM exprs = SCM_CDR (clause);
-
- const SCM um_exprs = unmemoize_exprs (exprs, env);
- const SCM um_labels = (scm_is_eq (labels, SCM_IM_ELSE))
- ? scm_sym_else
- : scm_i_finite_list_copy (labels);
- const SCM um_clause = scm_cons (um_labels, um_exprs);
-
- um_clauses = scm_cons (um_clause, um_clauses);
- }
- um_clauses = scm_reverse_x (um_clauses, SCM_UNDEFINED);
-
- return scm_cons2 (scm_sym_case, um_key_expr, um_clauses);
-}
-
-
-SCM_SYNTAX (s_cond, "cond", scm_i_makbimacro, scm_m_cond);
-SCM_GLOBAL_SYMBOL (scm_sym_cond, s_cond);
-SCM_GLOBAL_SYMBOL (scm_sym_arrow, "=>");
-
-SCM
-scm_m_cond (SCM expr, SCM env)
-{
- /* Check, whether 'else or '=> is a literal, i. e. not bound to a value. */
- const int else_literal_p = literal_p (scm_sym_else, env);
- const int arrow_literal_p = literal_p (scm_sym_arrow, env);
-
- const SCM clauses = SCM_CDR (expr);
- SCM clause_idx;
-
- ASSERT_SYNTAX (scm_ilength (clauses) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (clauses) >= 1, s_missing_clauses, expr);
-
- for (clause_idx = clauses;
- !scm_is_null (clause_idx);
- clause_idx = SCM_CDR (clause_idx))
- {
- SCM test;
-
- const SCM clause = SCM_CAR (clause_idx);
- const long length = scm_ilength (clause);
- ASSERT_SYNTAX_2 (length >= 1, s_bad_cond_clause, clause, expr);
-
- test = SCM_CAR (clause);
- if (scm_is_eq (test, scm_sym_else) && else_literal_p)
- {
- const int last_clause_p = scm_is_null (SCM_CDR (clause_idx));
- ASSERT_SYNTAX_2 (length >= 2,
- s_bad_cond_clause, clause, expr);
- ASSERT_SYNTAX_2 (last_clause_p,
- s_misplaced_else_clause, clause, expr);
- SCM_SETCAR (clause, SCM_IM_ELSE);
- }
- else if (length >= 2
- && scm_is_eq (SCM_CADR (clause), scm_sym_arrow)
- && arrow_literal_p)
- {
- ASSERT_SYNTAX_2 (length > 2, s_missing_recipient, clause, expr);
- ASSERT_SYNTAX_2 (length == 3, s_extra_expression, clause, expr);
- SCM_SETCAR (SCM_CDR (clause), SCM_IM_ARROW);
- }
- /* SRFI 61 extended cond */
- else if (length >= 3
- && scm_is_eq (SCM_CADDR (clause), scm_sym_arrow)
- && arrow_literal_p)
- {
- ASSERT_SYNTAX_2 (length > 3, s_missing_recipient, clause, expr);
- ASSERT_SYNTAX_2 (length == 4, s_extra_expression, clause, expr);
- SCM_SETCAR (SCM_CDDR (clause), SCM_IM_ARROW);
- }
- }
-
- SCM_SETCAR (expr, SCM_IM_COND);
- return expr;
-}
-
-static SCM
-unmemoize_cond (const SCM expr, const SCM env)
-{
- SCM um_clauses = SCM_EOL;
- SCM clause_idx;
-
- for (clause_idx = SCM_CDR (expr);
- !scm_is_null (clause_idx);
- clause_idx = SCM_CDR (clause_idx))
- {
- const SCM clause = SCM_CAR (clause_idx);
- const SCM sequence = SCM_CDR (clause);
- const SCM test = SCM_CAR (clause);
- SCM um_test;
- SCM um_sequence;
- SCM um_clause;
-
- if (scm_is_eq (test, SCM_IM_ELSE))
- um_test = scm_sym_else;
- else
- um_test = unmemoize_expression (test, env);
-
- if (!scm_is_null (sequence) && scm_is_eq (SCM_CAR (sequence),
- SCM_IM_ARROW))
- {
- const SCM target = SCM_CADR (sequence);
- const SCM um_target = unmemoize_expression (target, env);
- um_sequence = scm_list_2 (scm_sym_arrow, um_target);
- }
- else
- {
- um_sequence = unmemoize_exprs (sequence, env);
- }
-
- um_clause = scm_cons (um_test, um_sequence);
- um_clauses = scm_cons (um_clause, um_clauses);
- }
- um_clauses = scm_reverse_x (um_clauses, SCM_UNDEFINED);
-
- return scm_cons (scm_sym_cond, um_clauses);
-}
-
-
-SCM_SYNTAX (s_define, "define", scm_i_makbimacro, scm_m_define);
-SCM_GLOBAL_SYMBOL (scm_sym_define, s_define);
-
-/* Guile provides an extension to R5RS' define syntax to represent function
- * currying in a compact way. With this extension, it is allowed to write
- * (define <nested-variable> <body>), where <nested-variable> has of one of
- * the forms (<nested-variable> <formals>), (<nested-variable> . <formal>),
- * (<variable> <formals>) or (<variable> . <formal>). As in R5RS, <formals>
- * should be either a sequence of zero or more variables, or a sequence of one
- * or more variables followed by a space-delimited period and another
- * variable. Each level of argument nesting wraps the <body> within another
- * lambda expression. For example, the following forms are allowed, each one
- * followed by an equivalent, more explicit implementation.
- * Example 1:
- * (define ((a b . c) . d) <body>) is equivalent to
- * (define a (lambda (b . c) (lambda d <body>)))
- * Example 2:
- * (define (((a) b) c . d) <body>) is equivalent to
- * (define a (lambda () (lambda (b) (lambda (c . d) <body>))))
- */
-/* Dirk:FIXME:: We should provide an implementation for 'define' in the R5RS
- * module that does not implement this extension. */
-static SCM
-canonicalize_define (const SCM expr)
-{
- SCM body;
- SCM variable;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr);
-
- body = SCM_CDR (cdr_expr);
- variable = SCM_CAR (cdr_expr);
- while (scm_is_pair (variable))
- {
- /* This while loop realizes function currying by variable nesting.
- * Variable is known to be a nested-variable. In every iteration of the
- * loop another level of lambda expression is created, starting with the
- * innermost one. Note that we don't check for duplicate formals here:
- * This will be done by the memoizer of the lambda expression. */
- const SCM formals = SCM_CDR (variable);
- const SCM tail = scm_cons (formals, body);
-
- /* Add source properties to each new lambda expression: */
- const SCM lambda = scm_cons_source (variable, scm_sym_lambda, tail);
-
- body = scm_list_1 (lambda);
- variable = SCM_CAR (variable);
- }
- ASSERT_SYNTAX_2 (scm_is_symbol (variable), s_bad_variable, variable, expr);
- ASSERT_SYNTAX (scm_ilength (body) == 1, s_expression, expr);
-
- SCM_SETCAR (cdr_expr, variable);
- SCM_SETCDR (cdr_expr, body);
- return expr;
-}
-
-/* According to Section 5.2.1 of R5RS we first have to make sure that the
- variable is bound, and then perform the `(set! variable expression)'
- operation. However, EXPRESSION _can_ be evaluated before VARIABLE is
- bound. This means that EXPRESSION won't necessarily be able to assign
- values to VARIABLE as in `(define foo (begin (set! foo 1) (+ foo 1)))'. */
-SCM
-scm_m_define (SCM expr, SCM env)
-{
- ASSERT_SYNTAX (SCM_TOP_LEVEL (env), s_bad_define, expr);
-
- {
- const SCM canonical_definition = canonicalize_define (expr);
- const SCM cdr_canonical_definition = SCM_CDR (canonical_definition);
- const SCM variable = SCM_CAR (cdr_canonical_definition);
- const SCM value = scm_eval_car (SCM_CDR (cdr_canonical_definition), env);
- const SCM location
- = scm_sym2var (variable, scm_env_top_level (env), SCM_BOOL_T);
-
- if (SCM_REC_PROCNAMES_P)
- {
- SCM tmp = value;
- while (SCM_MACROP (tmp))
- tmp = SCM_MACRO_CODE (tmp);
- if (scm_is_true (scm_procedure_p (tmp))
- /* Only the first definition determines the name. */
- && scm_is_false (scm_procedure_property (tmp, scm_sym_name)))
- scm_set_procedure_property_x (tmp, scm_sym_name, variable);
- }
-
- SCM_VARIABLE_SET (location, value);
-
- return SCM_UNSPECIFIED;
- }
-}
-
-
-/* This is a helper function for forms (<keyword> <expression>) that are
- * transformed into (#@<keyword> '() <memoized_expression>) in order to allow
- * for easy creation of a thunk (i. e. a closure without arguments) using the
- * ('() <memoized_expression>) tail of the memoized form. */
-static SCM
-memoize_as_thunk_prototype (const SCM expr, const SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr);
-
- SCM_SETCDR (expr, scm_cons (SCM_EOL, cdr_expr));
-
- return expr;
-}
-
-
-SCM_SYNTAX (s_delay, "delay", scm_i_makbimacro, scm_m_delay);
-SCM_GLOBAL_SYMBOL (scm_sym_delay, s_delay);
-
-/* Promises are implemented as closures with an empty parameter list. Thus,
- * (delay <expression>) is transformed into (#@delay '() <expression>), where
- * the empty list represents the empty parameter list. This representation
- * allows for easy creation of the closure during evaluation. */
-SCM
-scm_m_delay (SCM expr, SCM env)
-{
- const SCM new_expr = memoize_as_thunk_prototype (expr, env);
- SCM_SETCAR (new_expr, SCM_IM_DELAY);
- return new_expr;
-}
-
-static SCM
-unmemoize_delay (const SCM expr, const SCM env)
-{
- const SCM thunk_expr = SCM_CADDR (expr);
- /* A promise is implemented as a closure, and when applying a
- closure the evaluator adds a new frame to the environment - even
- though, in the case of a promise, the added frame is always
- empty. We need to extend the environment here in the same way,
- so that any ILOCs in thunk_expr can be unmemoized correctly. */
- const SCM new_env = SCM_EXTEND_ENV (SCM_EOL, SCM_EOL, env);
- return scm_list_2 (scm_sym_delay, unmemoize_expression (thunk_expr, new_env));
-}
-
-
-SCM_SYNTAX(s_do, "do", scm_i_makbimacro, scm_m_do);
-SCM_GLOBAL_SYMBOL(scm_sym_do, s_do);
-
-/* DO gets the most radically altered syntax. The order of the vars is
- * reversed here. During the evaluation this allows for simple consing of the
- * results of the inits and steps:
-
- (do ((<var1> <init1> <step1>)
- (<var2> <init2>)
- ... )
- (<test> <return>)
- <body>)
-
- ;; becomes
-
- (#@do (<init1> <init2> ... <initn>)
- (varn ... var2 var1)
- (<test> <return>)
- (<body>)
- <step1> <step2> ... <stepn>) ;; missing steps replaced by var
- */
-SCM
-scm_m_do (SCM expr, SCM env SCM_UNUSED)
-{
- SCM variables = SCM_EOL;
- SCM init_forms = SCM_EOL;
- SCM step_forms = SCM_EOL;
- SCM binding_idx;
- SCM cddr_expr;
- SCM exit_clause;
- SCM commands;
- SCM tail;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr);
-
- /* Collect variables, init and step forms. */
- binding_idx = SCM_CAR (cdr_expr);
- ASSERT_SYNTAX_2 (scm_ilength (binding_idx) >= 0,
- s_bad_bindings, binding_idx, expr);
- for (; !scm_is_null (binding_idx); binding_idx = SCM_CDR (binding_idx))
- {
- const SCM binding = SCM_CAR (binding_idx);
- const long length = scm_ilength (binding);
- ASSERT_SYNTAX_2 (length == 2 || length == 3,
- s_bad_binding, binding, expr);
-
- {
- const SCM name = SCM_CAR (binding);
- const SCM init = SCM_CADR (binding);
- const SCM step = (length == 2) ? name : SCM_CADDR (binding);
- ASSERT_SYNTAX_2 (scm_is_symbol (name), s_bad_variable, name, expr);
- ASSERT_SYNTAX_2 (scm_is_false (scm_c_memq (name, variables)),
- s_duplicate_binding, name, expr);
-
- variables = scm_cons (name, variables);
- init_forms = scm_cons (init, init_forms);
- step_forms = scm_cons (step, step_forms);
- }
- }
- init_forms = scm_reverse_x (init_forms, SCM_UNDEFINED);
- step_forms = scm_reverse_x (step_forms, SCM_UNDEFINED);
-
- /* Memoize the test form and the exit sequence. */
- cddr_expr = SCM_CDR (cdr_expr);
- exit_clause = SCM_CAR (cddr_expr);
- ASSERT_SYNTAX_2 (scm_ilength (exit_clause) >= 1,
- s_bad_exit_clause, exit_clause, expr);
-
- commands = SCM_CDR (cddr_expr);
- tail = scm_cons2 (exit_clause, commands, step_forms);
- tail = scm_cons2 (init_forms, variables, tail);
- SCM_SETCAR (expr, SCM_IM_DO);
- SCM_SETCDR (expr, tail);
- return expr;
-}
-
-static SCM
-unmemoize_do (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM rnames = SCM_CAR (cddr_expr);
- const SCM extended_env = SCM_EXTEND_ENV (rnames, SCM_EOL, env);
- const SCM cdddr_expr = SCM_CDR (cddr_expr);
- const SCM exit_sequence = SCM_CAR (cdddr_expr);
- const SCM um_exit_sequence = unmemoize_exprs (exit_sequence, extended_env);
- const SCM cddddr_expr = SCM_CDR (cdddr_expr);
- const SCM um_body = unmemoize_exprs (SCM_CAR (cddddr_expr), extended_env);
-
- /* build transformed binding list */
- SCM um_names = scm_reverse (rnames);
- SCM um_inits = unmemoize_exprs (SCM_CAR (cdr_expr), env);
- SCM um_steps = unmemoize_exprs (SCM_CDR (cddddr_expr), extended_env);
- SCM um_bindings = SCM_EOL;
- while (!scm_is_null (um_names))
- {
- const SCM name = SCM_CAR (um_names);
- const SCM init = SCM_CAR (um_inits);
- SCM step = SCM_CAR (um_steps);
- step = scm_is_eq (step, name) ? SCM_EOL : scm_list_1 (step);
-
- um_bindings = scm_cons (scm_cons2 (name, init, step), um_bindings);
-
- um_names = SCM_CDR (um_names);
- um_inits = SCM_CDR (um_inits);
- um_steps = SCM_CDR (um_steps);
- }
- um_bindings = scm_reverse_x (um_bindings, SCM_UNDEFINED);
-
- return scm_cons (scm_sym_do,
- scm_cons2 (um_bindings, um_exit_sequence, um_body));
-}
-
-
-SCM_SYNTAX (s_if, "if", scm_i_makbimacro, scm_m_if);
-SCM_GLOBAL_SYMBOL (scm_sym_if, s_if);
-
-SCM
-scm_m_if (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const long length = scm_ilength (cdr_expr);
- ASSERT_SYNTAX (length == 2 || length == 3, s_expression, expr);
- SCM_SETCAR (expr, SCM_IM_IF);
- return expr;
-}
-
-static SCM
-unmemoize_if (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM um_condition = unmemoize_expression (SCM_CAR (cdr_expr), env);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM um_then = unmemoize_expression (SCM_CAR (cddr_expr), env);
- const SCM cdddr_expr = SCM_CDR (cddr_expr);
-
- if (scm_is_null (cdddr_expr))
- {
- return scm_list_3 (scm_sym_if, um_condition, um_then);
- }
- else
- {
- const SCM um_else = unmemoize_expression (SCM_CAR (cdddr_expr), env);
- return scm_list_4 (scm_sym_if, um_condition, um_then, um_else);
- }
-}
-
-
-SCM_SYNTAX (s_lambda, "lambda", scm_i_makbimacro, scm_m_lambda);
-SCM_GLOBAL_SYMBOL (scm_sym_lambda, s_lambda);
-
-/* A helper function for memoize_lambda to support checking for duplicate
- * formal arguments: Return true if OBJ is `eq?' to one of the elements of
- * LIST or to the cdr of the last cons. Therefore, LIST may have any of the
- * forms that a formal argument can have:
- * <rest>, (<arg1> ...), (<arg1> ... . <rest>) */
-static int
-c_improper_memq (SCM obj, SCM list)
-{
- for (; scm_is_pair (list); list = SCM_CDR (list))
- {
- if (scm_is_eq (SCM_CAR (list), obj))
- return 1;
- }
- return scm_is_eq (list, obj);
-}
-
-SCM
-scm_m_lambda (SCM expr, SCM env SCM_UNUSED)
-{
- SCM formals;
- SCM formals_idx;
- SCM cddr_expr;
- int documentation;
- SCM body;
- SCM new_body;
-
- const SCM cdr_expr = SCM_CDR (expr);
- const long length = scm_ilength (cdr_expr);
- ASSERT_SYNTAX (length >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (length >= 2, s_missing_expression, expr);
-
- /* Before iterating the list of formal arguments, make sure the formals
- * actually are given as either a symbol or a non-cyclic list. */
- formals = SCM_CAR (cdr_expr);
- if (scm_is_pair (formals))
- {
- /* Dirk:FIXME:: We should check for a cyclic list of formals, and if
- * detected, report a 'Bad formals' error. */
- }
- else
- {
- ASSERT_SYNTAX_2 (scm_is_symbol (formals) || scm_is_null (formals),
- s_bad_formals, formals, expr);
- }
-
- /* Now iterate the list of formal arguments to check if all formals are
- * symbols, and that there are no duplicates. */
- formals_idx = formals;
- while (scm_is_pair (formals_idx))
- {
- const SCM formal = SCM_CAR (formals_idx);
- const SCM next_idx = SCM_CDR (formals_idx);
- ASSERT_SYNTAX_2 (scm_is_symbol (formal), s_bad_formal, formal, expr);
- ASSERT_SYNTAX_2 (!c_improper_memq (formal, next_idx),
- s_duplicate_formal, formal, expr);
- formals_idx = next_idx;
- }
- ASSERT_SYNTAX_2 (scm_is_null (formals_idx) || scm_is_symbol (formals_idx),
- s_bad_formal, formals_idx, expr);
-
- /* Memoize the body. Keep a potential documentation string. */
- /* Dirk:FIXME:: We should probably extract the documentation string to
- * some external database. Otherwise it will slow down execution, since
- * the documentation string will have to be skipped with every execution
- * of the closure. */
- cddr_expr = SCM_CDR (cdr_expr);
- documentation = (length >= 3 && scm_is_string (SCM_CAR (cddr_expr)));
- body = documentation ? SCM_CDR (cddr_expr) : cddr_expr;
- new_body = m_body (SCM_IM_LAMBDA, body);
-
- SCM_SETCAR (expr, SCM_IM_LAMBDA);
- if (documentation)
- SCM_SETCDR (cddr_expr, new_body);
- else
- SCM_SETCDR (cdr_expr, new_body);
- return expr;
-}
-
-static SCM
-unmemoize_lambda (const SCM expr, const SCM env)
-{
- const SCM formals = SCM_CADR (expr);
- const SCM body = SCM_CDDR (expr);
-
- const SCM new_env = SCM_EXTEND_ENV (formals, SCM_EOL, env);
- const SCM um_formals = scm_i_finite_list_copy (formals);
- const SCM um_body = unmemoize_exprs (body, new_env);
-
- return scm_cons2 (scm_sym_lambda, um_formals, um_body);
-}
-
-
-/* Check if the format of the bindings is ((<symbol> <init-form>) ...). */
-static void
-check_bindings (const SCM bindings, const SCM expr)
-{
- SCM binding_idx;
-
- ASSERT_SYNTAX_2 (scm_ilength (bindings) >= 0,
- s_bad_bindings, bindings, expr);
-
- binding_idx = bindings;
- for (; !scm_is_null (binding_idx); binding_idx = SCM_CDR (binding_idx))
- {
- SCM name; /* const */
-
- const SCM binding = SCM_CAR (binding_idx);
- ASSERT_SYNTAX_2 (scm_ilength (binding) == 2,
- s_bad_binding, binding, expr);
-
- name = SCM_CAR (binding);
- ASSERT_SYNTAX_2 (scm_is_symbol (name), s_bad_variable, name, expr);
- }
-}
-
-
-/* The bindings, which must have the format ((v1 i1) (v2 i2) ... (vn in)), are
- * transformed to the lists (vn ... v2 v1) and (i1 i2 ... in). That is, the
- * variables are returned in a list with their order reversed, and the init
- * forms are returned in a list in the same order as they are given in the
- * bindings. If a duplicate variable name is detected, an error is
- * signalled. */
-static void
-transform_bindings (
- const SCM bindings, const SCM expr,
- SCM *const rvarptr, SCM *const initptr )
-{
- SCM rvariables = SCM_EOL;
- SCM rinits = SCM_EOL;
- SCM binding_idx = bindings;
- for (; !scm_is_null (binding_idx); binding_idx = SCM_CDR (binding_idx))
- {
- const SCM binding = SCM_CAR (binding_idx);
- const SCM cdr_binding = SCM_CDR (binding);
- const SCM name = SCM_CAR (binding);
- ASSERT_SYNTAX_2 (scm_is_false (scm_c_memq (name, rvariables)),
- s_duplicate_binding, name, expr);
- rvariables = scm_cons (name, rvariables);
- rinits = scm_cons (SCM_CAR (cdr_binding), rinits);
- }
- *rvarptr = rvariables;
- *initptr = scm_reverse_x (rinits, SCM_UNDEFINED);
-}
-
-
-SCM_SYNTAX(s_let, "let", scm_i_makbimacro, scm_m_let);
-SCM_GLOBAL_SYMBOL(scm_sym_let, s_let);
-
-/* This function is a helper function for memoize_let. It transforms
- * (let name ((var init) ...) body ...) into
- * ((letrec ((name (lambda (var ...) body ...))) name) init ...)
- * and memoizes the expression. It is assumed that the caller has checked
- * that name is a symbol and that there are bindings and a body. */
-static SCM
-memoize_named_let (const SCM expr, const SCM env SCM_UNUSED)
-{
- SCM rvariables;
- SCM variables;
- SCM inits;
-
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM name = SCM_CAR (cdr_expr);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM bindings = SCM_CAR (cddr_expr);
- check_bindings (bindings, expr);
-
- transform_bindings (bindings, expr, &rvariables, &inits);
- variables = scm_reverse_x (rvariables, SCM_UNDEFINED);
-
- {
- const SCM let_body = SCM_CDR (cddr_expr);
- const SCM lambda_body = m_body (SCM_IM_LET, let_body);
- const SCM lambda_tail = scm_cons (variables, lambda_body);
- const SCM lambda_form = scm_cons_source (expr, scm_sym_lambda, lambda_tail);
-
- const SCM rvar = scm_list_1 (name);
- const SCM init = scm_list_1 (lambda_form);
- const SCM body = m_body (SCM_IM_LET, scm_list_1 (name));
- const SCM letrec_tail = scm_cons (rvar, scm_cons (init, body));
- const SCM letrec_form = scm_cons_source (expr, SCM_IM_LETREC, letrec_tail);
- return scm_cons_source (expr, letrec_form, inits);
- }
-}
-
-/* (let ((v1 i1) (v2 i2) ...) body) with variables v1 .. vn and initializers
- * i1 .. in is transformed to (#@let (vn ... v2 v1) (i1 i2 ...) body). */
-SCM
-scm_m_let (SCM expr, SCM env)
-{
- SCM bindings;
-
- const SCM cdr_expr = SCM_CDR (expr);
- const long length = scm_ilength (cdr_expr);
- ASSERT_SYNTAX (length >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (length >= 2, s_missing_expression, expr);
-
- bindings = SCM_CAR (cdr_expr);
- if (scm_is_symbol (bindings))
- {
- ASSERT_SYNTAX (length >= 3, s_missing_expression, expr);
- return memoize_named_let (expr, env);
- }
-
- check_bindings (bindings, expr);
- if (scm_is_null (bindings) || scm_is_null (SCM_CDR (bindings)))
- {
- /* Special case: no bindings or single binding => let* is faster. */
- const SCM body = m_body (SCM_IM_LET, SCM_CDR (cdr_expr));
- return scm_m_letstar (scm_cons2 (SCM_CAR (expr), bindings, body), env);
- }
- else
- {
- /* plain let */
- SCM rvariables;
- SCM inits;
- transform_bindings (bindings, expr, &rvariables, &inits);
-
- {
- const SCM new_body = m_body (SCM_IM_LET, SCM_CDR (cdr_expr));
- const SCM new_tail = scm_cons2 (rvariables, inits, new_body);
- SCM_SETCAR (expr, SCM_IM_LET);
- SCM_SETCDR (expr, new_tail);
- return expr;
- }
- }
-}
-
-static SCM
-build_binding_list (SCM rnames, SCM rinits)
-{
- SCM bindings = SCM_EOL;
- while (!scm_is_null (rnames))
- {
- const SCM binding = scm_list_2 (SCM_CAR (rnames), SCM_CAR (rinits));
- bindings = scm_cons (binding, bindings);
- rnames = SCM_CDR (rnames);
- rinits = SCM_CDR (rinits);
- }
- return bindings;
-}
-
-static SCM
-unmemoize_let (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM um_rnames = SCM_CAR (cdr_expr);
- const SCM extended_env = SCM_EXTEND_ENV (um_rnames, SCM_EOL, env);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM um_inits = unmemoize_exprs (SCM_CAR (cddr_expr), env);
- const SCM um_rinits = scm_reverse_x (um_inits, SCM_UNDEFINED);
- const SCM um_bindings = build_binding_list (um_rnames, um_rinits);
- const SCM um_body = unmemoize_exprs (SCM_CDR (cddr_expr), extended_env);
-
- return scm_cons2 (scm_sym_let, um_bindings, um_body);
-}
-
-
-SCM_SYNTAX(s_letrec, "letrec", scm_i_makbimacro, scm_m_letrec);
-SCM_GLOBAL_SYMBOL(scm_sym_letrec, s_letrec);
-
-SCM
-scm_m_letrec (SCM expr, SCM env)
-{
- SCM bindings;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr);
-
- bindings = SCM_CAR (cdr_expr);
- if (scm_is_null (bindings))
- {
- /* no bindings, let* is executed faster */
- SCM body = m_body (SCM_IM_LETREC, SCM_CDR (cdr_expr));
- return scm_m_letstar (scm_cons2 (SCM_CAR (expr), SCM_EOL, body), env);
- }
- else
- {
- SCM rvariables;
- SCM inits;
- SCM new_body;
-
- check_bindings (bindings, expr);
- transform_bindings (bindings, expr, &rvariables, &inits);
- new_body = m_body (SCM_IM_LETREC, SCM_CDR (cdr_expr));
- return scm_cons2 (SCM_IM_LETREC, rvariables, scm_cons (inits, new_body));
- }
-}
-
-static SCM
-unmemoize_letrec (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM um_rnames = SCM_CAR (cdr_expr);
- const SCM extended_env = SCM_EXTEND_ENV (um_rnames, SCM_EOL, env);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM um_inits = unmemoize_exprs (SCM_CAR (cddr_expr), extended_env);
- const SCM um_rinits = scm_reverse_x (um_inits, SCM_UNDEFINED);
- const SCM um_bindings = build_binding_list (um_rnames, um_rinits);
- const SCM um_body = unmemoize_exprs (SCM_CDR (cddr_expr), extended_env);
-
- return scm_cons2 (scm_sym_letrec, um_bindings, um_body);
-}
-
-
-
-SCM_SYNTAX (s_letstar, "let*", scm_i_makbimacro, scm_m_letstar);
-SCM_GLOBAL_SYMBOL (scm_sym_letstar, s_letstar);
-
-/* (let* ((v1 i1) (v2 i2) ...) body) with variables v1 .. vn and initializers
- * i1 .. in is transformed into the form (#@let* (v1 i1 v2 i2 ...) body). */
-SCM
-scm_m_letstar (SCM expr, SCM env SCM_UNUSED)
-{
- SCM binding_idx;
- SCM new_body;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr);
-
- binding_idx = SCM_CAR (cdr_expr);
- check_bindings (binding_idx, expr);
-
- /* Transform ((v1 i1) (v2 i2) ...) into (v1 i1 v2 i2 ...). The
- * transformation is done in place. At the beginning of one iteration of
- * the loop the variable binding_idx holds the form
- * P1:( (vn . P2:(in . ())) . P3:( (vn+1 in+1) ... ) ),
- * where P1, P2 and P3 indicate the pairs, that are relevant for the
- * transformation. P1 and P2 are modified in the loop, P3 remains
- * untouched. After the execution of the loop, P1 will hold
- * P1:( vn . P2:(in . P3:( (vn+1 in+1) ... )) )
- * and binding_idx will hold P3. */
- while (!scm_is_null (binding_idx))
- {
- const SCM cdr_binding_idx = SCM_CDR (binding_idx); /* remember P3 */
- const SCM binding = SCM_CAR (binding_idx);
- const SCM name = SCM_CAR (binding);
- const SCM cdr_binding = SCM_CDR (binding);
-
- SCM_SETCDR (cdr_binding, cdr_binding_idx); /* update P2 */
- SCM_SETCAR (binding_idx, name); /* update P1 */
- SCM_SETCDR (binding_idx, cdr_binding); /* update P1 */
-
- binding_idx = cdr_binding_idx; /* continue with P3 */
- }
-
- new_body = m_body (SCM_IM_LETSTAR, SCM_CDR (cdr_expr));
- SCM_SETCAR (expr, SCM_IM_LETSTAR);
- /* the bindings have been changed in place */
- SCM_SETCDR (cdr_expr, new_body);
- return expr;
-}
-
-static SCM
-unmemoize_letstar (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM body = SCM_CDR (cdr_expr);
- SCM bindings = SCM_CAR (cdr_expr);
- SCM um_bindings = SCM_EOL;
- SCM extended_env = env;
- SCM um_body;
-
- while (!scm_is_null (bindings))
- {
- const SCM variable = SCM_CAR (bindings);
- const SCM init = SCM_CADR (bindings);
- const SCM um_init = unmemoize_expression (init, extended_env);
- um_bindings = scm_cons (scm_list_2 (variable, um_init), um_bindings);
- extended_env = SCM_EXTEND_ENV (variable, SCM_BOOL_F, extended_env);
- bindings = SCM_CDDR (bindings);
- }
- um_bindings = scm_reverse_x (um_bindings, SCM_UNDEFINED);
-
- um_body = unmemoize_exprs (body, extended_env);
-
- return scm_cons2 (scm_sym_letstar, um_bindings, um_body);
-}
-
-
-SCM_SYNTAX (s_or, "or", scm_i_makbimacro, scm_m_or);
-SCM_GLOBAL_SYMBOL (scm_sym_or, s_or);
-
-SCM
-scm_m_or (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const long length = scm_ilength (cdr_expr);
-
- ASSERT_SYNTAX (length >= 0, s_bad_expression, expr);
-
- if (length == 0)
- {
- /* Special case: (or) is replaced by #f. */
- return SCM_BOOL_F;
- }
- else
- {
- SCM_SETCAR (expr, SCM_IM_OR);
- return expr;
- }
-}
-
-static SCM
-unmemoize_or (const SCM expr, const SCM env)
-{
- return scm_cons (scm_sym_or, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-SCM_SYNTAX (s_quasiquote, "quasiquote", scm_makacro, scm_m_quasiquote);
-SCM_GLOBAL_SYMBOL (scm_sym_quasiquote, s_quasiquote);
-SCM_GLOBAL_SYMBOL (scm_sym_unquote, "unquote");
-SCM_GLOBAL_SYMBOL (scm_sym_uq_splicing, "unquote-splicing");
-
-/* Internal function to handle a quasiquotation: 'form' is the parameter in
- * the call (quasiquotation form), 'env' is the environment where unquoted
- * expressions will be evaluated, and 'depth' is the current quasiquotation
- * nesting level and is known to be greater than zero. */
-static SCM
-iqq (SCM form, SCM env, unsigned long int depth)
-{
- if (scm_is_pair (form))
- {
- const SCM tmp = SCM_CAR (form);
- if (scm_is_eq (tmp, scm_sym_quasiquote))
- {
- const SCM args = SCM_CDR (form);
- ASSERT_SYNTAX (scm_ilength (args) == 1, s_expression, form);
- return scm_list_2 (tmp, iqq (SCM_CAR (args), env, depth + 1));
- }
- else if (scm_is_eq (tmp, scm_sym_unquote))
- {
- const SCM args = SCM_CDR (form);
- ASSERT_SYNTAX (scm_ilength (args) == 1, s_expression, form);
- if (depth - 1 == 0)
- return scm_eval_car (args, env);
- else
- return scm_list_2 (tmp, iqq (SCM_CAR (args), env, depth - 1));
- }
- else if (scm_is_pair (tmp)
- && scm_is_eq (SCM_CAR (tmp), scm_sym_uq_splicing))
- {
- const SCM args = SCM_CDR (tmp);
- ASSERT_SYNTAX (scm_ilength (args) == 1, s_expression, form);
- if (depth - 1 == 0)
- {
- const SCM list = scm_eval_car (args, env);
- const SCM rest = SCM_CDR (form);
- ASSERT_SYNTAX_2 (scm_ilength (list) >= 0,
- s_splicing, list, form);
- return scm_append (scm_list_2 (list, iqq (rest, env, depth)));
- }
- else
- return scm_cons (iqq (SCM_CAR (form), env, depth - 1),
- iqq (SCM_CDR (form), env, depth));
- }
- else
- return scm_cons (iqq (SCM_CAR (form), env, depth),
- iqq (SCM_CDR (form), env, depth));
- }
- else if (scm_is_vector (form))
- return scm_vector (iqq (scm_vector_to_list (form), env, depth));
- else
- return form;
-}
-
-SCM
-scm_m_quasiquote (SCM expr, SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr);
- return iqq (SCM_CAR (cdr_expr), env, 1);
-}
-
-
-SCM_SYNTAX (s_quote, "quote", scm_i_makbimacro, scm_m_quote);
-SCM_GLOBAL_SYMBOL (scm_sym_quote, s_quote);
-
-SCM
-scm_m_quote (SCM expr, SCM env SCM_UNUSED)
-{
- SCM quotee;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr);
- quotee = SCM_CAR (cdr_expr);
- if (is_self_quoting_p (quotee))
- return quotee;
-
- SCM_SETCAR (expr, SCM_IM_QUOTE);
- SCM_SETCDR (expr, quotee);
- return expr;
-}
-
-static SCM
-unmemoize_quote (const SCM expr, const SCM env SCM_UNUSED)
-{
- return scm_list_2 (scm_sym_quote, SCM_CDR (expr));
-}
-
-
-/* Will go into the RnRS module when Guile is factorized.
-SCM_SYNTAX (s_set_x, "set!", scm_i_makbimacro, scm_m_set_x); */
-static const char s_set_x[] = "set!";
-SCM_GLOBAL_SYMBOL (scm_sym_set_x, s_set_x);
-
-SCM
-scm_m_set_x (SCM expr, SCM env SCM_UNUSED)
-{
- SCM variable;
- SCM new_variable;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_expression, expr);
- variable = SCM_CAR (cdr_expr);
-
- /* Memoize the variable form. */
- ASSERT_SYNTAX_2 (scm_is_symbol (variable), s_bad_variable, variable, expr);
- new_variable = lookup_symbol (variable, env);
- /* Leave the memoization of unbound symbols to lazy memoization: */
- if (SCM_UNBNDP (new_variable))
- new_variable = variable;
-
- SCM_SETCAR (expr, SCM_IM_SET_X);
- SCM_SETCAR (cdr_expr, new_variable);
- return expr;
-}
-
-static SCM
-unmemoize_set_x (const SCM expr, const SCM env)
-{
- return scm_cons (scm_sym_set_x, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-/* Start of the memoizers for non-R5RS builtin macros. */
-
-
-SCM_SYNTAX (s_atapply, "@apply", scm_i_makbimacro, scm_m_apply);
-SCM_GLOBAL_SYMBOL (scm_sym_atapply, s_atapply);
-SCM_GLOBAL_SYMBOL (scm_sym_apply, s_atapply + 1);
-
-SCM
-scm_m_apply (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_missing_expression, expr);
-
- SCM_SETCAR (expr, SCM_IM_APPLY);
- return expr;
-}
-
-static SCM
-unmemoize_apply (const SCM expr, const SCM env)
-{
- return scm_list_2 (scm_sym_atapply, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-SCM_SYNTAX (s_atbind, "@bind", scm_i_makbimacro, scm_m_atbind);
-
-/* FIXME: The following explanation should go into the documentation: */
-/* (@bind ((var init) ...) body ...) will assign the values of the `init's to
- * the global variables named by `var's (symbols, not evaluated), creating
- * them if they don't exist, executes body, and then restores the previous
- * values of the `var's. Additionally, whenever control leaves body, the
- * values of the `var's are saved and restored when control returns. It is an
- * error when a symbol appears more than once among the `var's. All `init's
- * are evaluated before any `var' is set.
- *
- * Think of this as `let' for dynamic scope.
- */
-
-/* (@bind ((var1 exp1) ... (varn expn)) body ...) is memoized into
- * (#@bind ((varn ... var1) . (exp1 ... expn)) body ...).
- *
- * FIXME - also implement `@bind*'.
- */
-SCM
-scm_m_atbind (SCM expr, SCM env)
-{
- SCM bindings;
- SCM rvariables;
- SCM inits;
- SCM variable_idx;
-
- const SCM top_level = scm_env_top_level (env);
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr);
- bindings = SCM_CAR (cdr_expr);
- check_bindings (bindings, expr);
- transform_bindings (bindings, expr, &rvariables, &inits);
-
- for (variable_idx = rvariables;
- !scm_is_null (variable_idx);
- variable_idx = SCM_CDR (variable_idx))
- {
- /* The first call to scm_sym2var will look beyond the current module,
- * while the second call wont. */
- const SCM variable = SCM_CAR (variable_idx);
- SCM new_variable = scm_sym2var (variable, top_level, SCM_BOOL_F);
- if (scm_is_false (new_variable))
- new_variable = scm_sym2var (variable, top_level, SCM_BOOL_T);
- SCM_SETCAR (variable_idx, new_variable);
- }
-
- SCM_SETCAR (expr, SCM_IM_BIND);
- SCM_SETCAR (cdr_expr, scm_cons (rvariables, inits));
- return expr;
-}
-
-
-SCM_SYNTAX(s_atcall_cc, "@call-with-current-continuation", scm_i_makbimacro, scm_m_cont);
-SCM_GLOBAL_SYMBOL(scm_sym_atcall_cc, s_atcall_cc);
-
-SCM
-scm_m_cont (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr);
-
- SCM_SETCAR (expr, SCM_IM_CONT);
- return expr;
-}
-
-static SCM
-unmemoize_atcall_cc (const SCM expr, const SCM env)
-{
- return scm_list_2 (scm_sym_atcall_cc, unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-
-SCM_SYNTAX (s_at_call_with_values, "@call-with-values", scm_i_makbimacro, scm_m_at_call_with_values);
-SCM_GLOBAL_SYMBOL(scm_sym_at_call_with_values, s_at_call_with_values);
-
-SCM
-scm_m_at_call_with_values (SCM expr, SCM env SCM_UNUSED)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_expression, expr);
-
- SCM_SETCAR (expr, SCM_IM_CALL_WITH_VALUES);
- return expr;
-}
-
-static SCM
-unmemoize_at_call_with_values (const SCM expr, const SCM env)
-{
- return scm_list_2 (scm_sym_at_call_with_values,
- unmemoize_exprs (SCM_CDR (expr), env));
-}
-
-#if 0
-
-/* See futures.h for a comment why futures are not enabled.
- */
-
-SCM_SYNTAX (s_future, "future", scm_i_makbimacro, scm_m_future);
-SCM_GLOBAL_SYMBOL (scm_sym_future, s_future);
-
-/* Like promises, futures are implemented as closures with an empty
- * parameter list. Thus, (future <expression>) is transformed into
- * (#@future '() <expression>), where the empty list represents the
- * empty parameter list. This representation allows for easy creation
- * of the closure during evaluation. */
-SCM
-scm_m_future (SCM expr, SCM env)
-{
- const SCM new_expr = memoize_as_thunk_prototype (expr, env);
- SCM_SETCAR (new_expr, SCM_IM_FUTURE);
- return new_expr;
-}
-
-static SCM
-unmemoize_future (const SCM expr, const SCM env)
-{
- const SCM thunk_expr = SCM_CADDR (expr);
- return scm_list_2 (scm_sym_future, unmemoize_expression (thunk_expr, env));
-}
-
-#endif
-
-SCM_SYNTAX (s_gset_x, "set!", scm_i_makbimacro, scm_m_generalized_set_x);
-SCM_SYMBOL (scm_sym_setter, "setter");
-
-SCM
-scm_m_generalized_set_x (SCM expr, SCM env)
-{
- SCM target, exp_target;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_expression, expr);
-
- target = SCM_CAR (cdr_expr);
- if (!scm_is_pair (target))
- {
- /* R5RS usage */
- return scm_m_set_x (expr, env);
- }
- else
- {
- /* (set! (foo bar ...) baz) becomes ((setter foo) bar ... baz) */
- /* Macroexpanding the target might return things of the form
- (begin <atom>). In that case, <atom> must be a symbol or a
- variable and we memoize to (set! <atom> ...).
- */
- exp_target = macroexp (target, env);
- if (scm_is_eq (SCM_CAR (exp_target), SCM_IM_BEGIN)
- && !scm_is_null (SCM_CDR (exp_target))
- && scm_is_null (SCM_CDDR (exp_target)))
- {
- exp_target= SCM_CADR (exp_target);
- ASSERT_SYNTAX_2 (scm_is_symbol (exp_target)
- || SCM_VARIABLEP (exp_target),
- s_bad_variable, exp_target, expr);
- return scm_cons (SCM_IM_SET_X, scm_cons (exp_target,
- SCM_CDR (cdr_expr)));
- }
- else
- {
- const SCM setter_proc_tail = scm_list_1 (SCM_CAR (target));
- const SCM setter_proc = scm_cons_source (expr, scm_sym_setter,
- setter_proc_tail);
-
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM setter_args = scm_append_x (scm_list_2 (SCM_CDR (target),
- cddr_expr));
-
- SCM_SETCAR (expr, setter_proc);
- SCM_SETCDR (expr, setter_args);
- return expr;
- }
- }
-}
-
-
-/* @slot-ref is bound privately in the (oop goops) module from goops.c. As
- * soon as the module system allows us to more freely create bindings in
- * arbitrary modules during the startup phase, the code from goops.c should be
- * moved here. */
-
-SCM_SYMBOL (sym_atslot_ref, "@slot-ref");
-
-SCM
-scm_m_atslot_ref (SCM expr, SCM env SCM_UNUSED)
-{
- SCM slot_nr;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_expression, expr);
- slot_nr = SCM_CADR (cdr_expr);
- ASSERT_SYNTAX_2 (SCM_I_INUMP (slot_nr), s_bad_slot_number, slot_nr, expr);
-
- SCM_SETCAR (expr, SCM_IM_SLOT_REF);
- SCM_SETCDR (cdr_expr, slot_nr);
- return expr;
-}
-
-static SCM
-unmemoize_atslot_ref (const SCM expr, const SCM env)
-{
- const SCM instance = SCM_CADR (expr);
- const SCM um_instance = unmemoize_expression (instance, env);
- const SCM slot_nr = SCM_CDDR (expr);
- return scm_list_3 (sym_atslot_ref, um_instance, slot_nr);
-}
-
-
-/* @slot-set! is bound privately in the (oop goops) module from goops.c. As
- * soon as the module system allows us to more freely create bindings in
- * arbitrary modules during the startup phase, the code from goops.c should be
- * moved here. */
-
-SCM_SYMBOL (sym_atslot_set_x, "@slot-set!");
-
-SCM
-scm_m_atslot_set_x (SCM expr, SCM env SCM_UNUSED)
-{
- SCM slot_nr;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 3, s_expression, expr);
- slot_nr = SCM_CADR (cdr_expr);
- ASSERT_SYNTAX_2 (SCM_I_INUMP (slot_nr), s_bad_slot_number, slot_nr, expr);
-
- SCM_SETCAR (expr, SCM_IM_SLOT_SET_X);
- return expr;
-}
-
-static SCM
-unmemoize_atslot_set_x (const SCM expr, const SCM env)
-{
- const SCM cdr_expr = SCM_CDR (expr);
- const SCM instance = SCM_CAR (cdr_expr);
- const SCM um_instance = unmemoize_expression (instance, env);
- const SCM cddr_expr = SCM_CDR (cdr_expr);
- const SCM slot_nr = SCM_CAR (cddr_expr);
- const SCM cdddr_expr = SCM_CDR (cddr_expr);
- const SCM value = SCM_CAR (cdddr_expr);
- const SCM um_value = unmemoize_expression (value, env);
- return scm_list_4 (sym_atslot_set_x, um_instance, slot_nr, um_value);
-}
-
-
-#if SCM_ENABLE_ELISP
-
-static const char s_defun[] = "Symbol's function definition is void";
-
-SCM_SYNTAX (s_nil_cond, "nil-cond", scm_i_makbimacro, scm_m_nil_cond);
-
-/* nil-cond expressions have the form
- * (nil-cond COND VAL COND VAL ... ELSEVAL) */
-SCM
-scm_m_nil_cond (SCM expr, SCM env SCM_UNUSED)
-{
- const long length = scm_ilength (SCM_CDR (expr));
- ASSERT_SYNTAX (length >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (length >= 1 && (length % 2) == 1, s_expression, expr);
-
- SCM_SETCAR (expr, SCM_IM_NIL_COND);
- return expr;
-}
-
-
-SCM_SYNTAX (s_atfop, "@fop", scm_i_makbimacro, scm_m_atfop);
-
-/* The @fop-macro handles procedure and macro applications for elisp. The
- * input expression must have the form
- * (@fop <var> (transformer-macro <expr> ...))
- * where <var> must be a symbol. The expression is transformed into the
- * memoized form of either
- * (apply <un-aliased var> (transformer-macro <expr> ...))
- * if the value of var (across all aliasing) is not a macro, or
- * (<un-aliased var> <expr> ...)
- * if var is a macro. */
-SCM
-scm_m_atfop (SCM expr, SCM env SCM_UNUSED)
-{
- SCM location;
- SCM symbol;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 1, s_missing_expression, expr);
-
- symbol = SCM_CAR (cdr_expr);
- ASSERT_SYNTAX_2 (scm_is_symbol (symbol), s_bad_variable, symbol, expr);
-
- location = scm_symbol_fref (symbol);
- ASSERT_SYNTAX_2 (SCM_VARIABLEP (location), s_defun, symbol, expr);
-
- /* The elisp function `defalias' allows to define aliases for symbols. To
- * look up such definitions, the chain of symbol definitions has to be
- * followed up to the terminal symbol. */
- while (scm_is_symbol (SCM_VARIABLE_REF (location)))
- {
- const SCM alias = SCM_VARIABLE_REF (location);
- location = scm_symbol_fref (alias);
- ASSERT_SYNTAX_2 (SCM_VARIABLEP (location), s_defun, symbol, expr);
- }
-
- /* Memoize the value location belonging to the terminal symbol. */
- SCM_SETCAR (cdr_expr, location);
-
- if (!SCM_MACROP (SCM_VARIABLE_REF (location)))
- {
- /* Since the location does not contain a macro, the form is a procedure
- * application. Replace `@fop' by `@apply' and transform the expression
- * including the `transformer-macro'. */
- SCM_SETCAR (expr, SCM_IM_APPLY);
- return expr;
- }
- else
- {
- /* Since the location contains a macro, the arguments should not be
- * transformed, so the `transformer-macro' is cut out. The resulting
- * expression starts with the memoized variable, that is at the cdr of
- * the input expression. */
- SCM_SETCDR (cdr_expr, SCM_CDADR (cdr_expr));
- return cdr_expr;
- }
-}
-
-#endif /* SCM_ENABLE_ELISP */
-
-
-static SCM
-unmemoize_builtin_macro (const SCM expr, const SCM env)
-{
- switch (ISYMNUM (SCM_CAR (expr)))
- {
- case (ISYMNUM (SCM_IM_AND)):
- return unmemoize_and (expr, env);
-
- case (ISYMNUM (SCM_IM_BEGIN)):
- return unmemoize_begin (expr, env);
-
- case (ISYMNUM (SCM_IM_CASE)):
- return unmemoize_case (expr, env);
-
- case (ISYMNUM (SCM_IM_COND)):
- return unmemoize_cond (expr, env);
-
- case (ISYMNUM (SCM_IM_DELAY)):
- return unmemoize_delay (expr, env);
-
- case (ISYMNUM (SCM_IM_DO)):
- return unmemoize_do (expr, env);
-
- case (ISYMNUM (SCM_IM_IF)):
- return unmemoize_if (expr, env);
-
- case (ISYMNUM (SCM_IM_LAMBDA)):
- return unmemoize_lambda (expr, env);
-
- case (ISYMNUM (SCM_IM_LET)):
- return unmemoize_let (expr, env);
-
- case (ISYMNUM (SCM_IM_LETREC)):
- return unmemoize_letrec (expr, env);
-
- case (ISYMNUM (SCM_IM_LETSTAR)):
- return unmemoize_letstar (expr, env);
-
- case (ISYMNUM (SCM_IM_OR)):
- return unmemoize_or (expr, env);
-
- case (ISYMNUM (SCM_IM_QUOTE)):
- return unmemoize_quote (expr, env);
-
- case (ISYMNUM (SCM_IM_SET_X)):
- return unmemoize_set_x (expr, env);
-
- case (ISYMNUM (SCM_IM_APPLY)):
- return unmemoize_apply (expr, env);
-
- case (ISYMNUM (SCM_IM_BIND)):
- return unmemoize_exprs (expr, env); /* FIXME */
-
- case (ISYMNUM (SCM_IM_CONT)):
- return unmemoize_atcall_cc (expr, env);
-
- case (ISYMNUM (SCM_IM_CALL_WITH_VALUES)):
- return unmemoize_at_call_with_values (expr, env);
-
-#if 0
- /* See futures.h for a comment why futures are not enabled.
- */
- case (ISYMNUM (SCM_IM_FUTURE)):
- return unmemoize_future (expr, env);
-#endif
-
- case (ISYMNUM (SCM_IM_SLOT_REF)):
- return unmemoize_atslot_ref (expr, env);
-
- case (ISYMNUM (SCM_IM_SLOT_SET_X)):
- return unmemoize_atslot_set_x (expr, env);
-
- case (ISYMNUM (SCM_IM_NIL_COND)):
- return unmemoize_exprs (expr, env); /* FIXME */
-
- default:
- return unmemoize_exprs (expr, env); /* FIXME */
- }
-}
-
-
-/* scm_i_unmemocopy_expr and scm_i_unmemocopy_body take a memoized expression
- * respectively a memoized body together with its environment and rewrite it
- * to its original form. Thus, these functions are the inversion of the
- * rewrite rules above. The procedure is not optimized for speed. It's used
- * in scm_i_unmemoize_expr, scm_procedure_source, macro_print and scm_iprin1.
- *
- * Unmemoizing is not a reliable process. You cannot in general expect to get
- * the original source back.
- *
- * However, GOOPS currently relies on this for method compilation. This ought
- * to change. */
-
-SCM
-scm_i_unmemocopy_expr (SCM expr, SCM env)
-{
- const SCM source_properties = scm_whash_lookup (scm_source_whash, expr);
- const SCM um_expr = unmemoize_expression (expr, env);
-
- if (scm_is_true (source_properties))
- scm_whash_insert (scm_source_whash, um_expr, source_properties);
-
- return um_expr;
-}
-
-SCM
-scm_i_unmemocopy_body (SCM forms, SCM env)
-{
- const SCM source_properties = scm_whash_lookup (scm_source_whash, forms);
- const SCM um_forms = unmemoize_exprs (forms, env);
-
- if (scm_is_true (source_properties))
- scm_whash_insert (scm_source_whash, um_forms, source_properties);
-
- return um_forms;
-}
-
-
-#if (SCM_ENABLE_DEPRECATED == 1)
-
-/* Deprecated in guile 1.7.0 on 2003-11-09. */
-SCM
-scm_m_expand_body (SCM exprs, SCM env)
-{
- scm_c_issue_deprecation_warning
- ("`scm_m_expand_body' is deprecated.");
- m_expand_body (exprs, env);
- return exprs;
-}
-
-
-SCM_SYNTAX (s_undefine, "undefine", scm_makacro, scm_m_undefine);
-
-SCM
-scm_m_undefine (SCM expr, SCM env)
-{
- SCM variable;
- SCM location;
-
- const SCM cdr_expr = SCM_CDR (expr);
- ASSERT_SYNTAX (SCM_TOP_LEVEL (env), "Bad undefine placement in", expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr);
- ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr);
-
- scm_c_issue_deprecation_warning
- ("`undefine' is deprecated.\n");
-
- variable = SCM_CAR (cdr_expr);
- ASSERT_SYNTAX_2 (scm_is_symbol (variable), s_bad_variable, variable, expr);
- location = scm_sym2var (variable, scm_env_top_level (env), SCM_BOOL_F);
- ASSERT_SYNTAX_2 (scm_is_true (location)
- && !SCM_UNBNDP (SCM_VARIABLE_REF (location)),
- "variable already unbound ", variable, expr);
- SCM_VARIABLE_SET (location, SCM_UNDEFINED);
- return SCM_UNSPECIFIED;
-}
-
-SCM
-scm_macroexp (SCM x, SCM env)
-{
- scm_c_issue_deprecation_warning
- ("`scm_macroexp' is deprecated.");
- return macroexp (x, env);
-}
-
-#endif
-
-
-#if (SCM_ENABLE_DEPRECATED == 1)
-
-SCM
-scm_unmemocar (SCM form, SCM env)
-{
- scm_c_issue_deprecation_warning
- ("`scm_unmemocar' is deprecated.");
-
- if (!scm_is_pair (form))
- return form;
- else
- {
- SCM c = SCM_CAR (form);
- if (SCM_VARIABLEP (c))
- {
- SCM sym = scm_module_reverse_lookup (scm_env_module (env), c);
- if (scm_is_false (sym))
- sym = sym_three_question_marks;
- SCM_SETCAR (form, sym);
- }
- else if (SCM_ILOCP (c))
- {
- unsigned long int ir;
-
- for (ir = SCM_IFRAME (c); ir != 0; --ir)
- env = SCM_CDR (env);
- env = SCM_CAAR (env);
- for (ir = SCM_IDIST (c); ir != 0; --ir)
- env = SCM_CDR (env);
-
- SCM_SETCAR (form, SCM_ICDRP (c) ? env : SCM_CAR (env));
- }
- return form;
- }
-}
-
-#endif
-
-/*****************************************************************************/
-/*****************************************************************************/
-/* The definitions for execution start here. */
-/*****************************************************************************/
-/*****************************************************************************/
-
-SCM_GLOBAL_SYMBOL (scm_sym_enter_frame, "enter-frame");
-SCM_GLOBAL_SYMBOL (scm_sym_apply_frame, "apply-frame");
-SCM_GLOBAL_SYMBOL (scm_sym_exit_frame, "exit-frame");
-SCM_GLOBAL_SYMBOL (scm_sym_memoize_symbol, "memoize-symbol");
-SCM_GLOBAL_SYMBOL (scm_sym_trace, "trace");
-SCM_SYMBOL (sym_instead, "instead");
-
-/* A function object to implement "apply" for non-closure functions. */
-static SCM f_apply;
-/* An endless list consisting of #<undefined> objects: */
-static SCM undefineds;
-
-
-int
-scm_badargsp (SCM formals, SCM args)
-{
- while (!scm_is_null (formals))
- {
- if (!scm_is_pair (formals))
- return 0;
- if (scm_is_null (args))
- return 1;
- formals = SCM_CDR (formals);
- args = SCM_CDR (args);
- }
- return !scm_is_null (args) ? 1 : 0;
-}
-
-\f
-
-/* The evaluator contains a plethora of EVAL symbols.
- *
- *
- * SCM_I_EVALIM is used when it is known that the expression is an
- * immediate. (This macro never calls an evaluator.)
- *
- * SCM_I_XEVAL evaluates an expression that is expected to have its symbols already
- * memoized. Expressions that are not of the form '(<form> <form> ...)' are
- * evaluated inline without calling an evaluator.
- *
- * This macro uses ceval or deval depending on its 3rd argument.
- *
- * SCM_I_XEVALCAR evaluates the car of an expression 'X:(Y:<form> <form> ...)',
- * potentially replacing a symbol at the position Y:<form> by its memoized
- * variable. If Y:<form> is not of the form '(<form> <form> ...)', the
- * evaluation is performed inline without calling an evaluator.
- *
- * This macro uses ceval or deval depending on its 3rd argument.
- *
- */
-
-#define SCM_I_EVALIM2(x) \
- ((scm_is_eq ((x), SCM_EOL) \
- ? syntax_error (s_empty_combination, (x), SCM_UNDEFINED), 0 \
- : 0), \
- (x))
-
-#define SCM_I_EVALIM(x, env) (SCM_ILOCP (x) \
- ? *scm_ilookup ((x), (env)) \
- : SCM_I_EVALIM2(x))
-
-#define SCM_I_XEVAL(x, env, debug_p) \
- (SCM_IMP (x) \
- ? SCM_I_EVALIM2 (x) \
- : (SCM_VARIABLEP (x) \
- ? SCM_VARIABLE_REF (x) \
- : (scm_is_pair (x) \
- ? (debug_p \
- ? deval ((x), (env)) \
- : ceval ((x), (env))) \
- : (x))))
-
-#define SCM_I_XEVALCAR(x, env, debug_p) \
- (SCM_IMP (SCM_CAR (x)) \
- ? SCM_I_EVALIM (SCM_CAR (x), (env)) \
- : (SCM_VARIABLEP (SCM_CAR (x)) \
- ? SCM_VARIABLE_REF (SCM_CAR (x)) \
- : (scm_is_pair (SCM_CAR (x)) \
- ? (debug_p \
- ? deval (SCM_CAR (x), (env)) \
- : ceval (SCM_CAR (x), (env))) \
- : (!scm_is_symbol (SCM_CAR (x)) \
- ? SCM_CAR (x) \
- : *scm_lookupcar ((x), (env), 1)))))
-
-scm_i_pthread_mutex_t source_mutex;
-
-
-/* Lookup a given local variable in an environment. The local variable is
- * given as an iloc, that is a triple <frame, binding, last?>, where frame
- * indicates the relative number of the environment frame (counting upwards
- * from the innermost environment frame), binding indicates the number of the
- * binding within the frame, and last? (which is extracted from the iloc using
- * the macro SCM_ICDRP) indicates whether the binding forms the binding at the
- * very end of the improper list of bindings. */
-SCM *
-scm_ilookup (SCM iloc, SCM env)
-{
- unsigned int frame_nr = SCM_IFRAME (iloc);
- unsigned int binding_nr = SCM_IDIST (iloc);
- SCM frames = env;
- SCM bindings;
-
- for (; 0 != frame_nr; --frame_nr)
- frames = SCM_CDR (frames);
-
- bindings = SCM_CAR (frames);
- for (; 0 != binding_nr; --binding_nr)
- bindings = SCM_CDR (bindings);
-
- if (SCM_ICDRP (iloc))
- return SCM_CDRLOC (bindings);
- return SCM_CARLOC (SCM_CDR (bindings));
-}
-
-
-SCM_SYMBOL (scm_unbound_variable_key, "unbound-variable");
-
-static void error_unbound_variable (SCM symbol) SCM_NORETURN;
-static void error_defined_variable (SCM symbol) SCM_NORETURN;
-
-/* Call this for variables that are unfound.
- */
-static void
-error_unbound_variable (SCM symbol)
-{
- scm_error (scm_unbound_variable_key, NULL,
- "Unbound variable: ~S",
- scm_list_1 (symbol), SCM_BOOL_F);
-}
-
-/* Call this for variables that are found but contain SCM_UNDEFINED.
- */
-static void
-error_defined_variable (SCM symbol)
-{
- /* We use the 'unbound-variable' key here as well, since it
- basically is the same kind of error, with a slight variation in
- the displayed message.
- */
- scm_error (scm_unbound_variable_key, NULL,
- "Variable used before given a value: ~S",
- scm_list_1 (symbol), SCM_BOOL_F);
-}
-
-
-/* The Lookup Car Race
- - by Eva Luator
-
- Memoization of variables and special forms is done while executing
- the code for the first time. As long as there is only one thread
- everything is fine, but as soon as two threads execute the same
- code concurrently `for the first time' they can come into conflict.
-
- This memoization includes rewriting variable references into more
- efficient forms and expanding macros. Furthermore, macro expansion
- includes `compiling' special forms like `let', `cond', etc. into
- tree-code instructions.
-
- There shouldn't normally be a problem with memoizing local and
- global variable references (into ilocs and variables), because all
- threads will mutate the code in *exactly* the same way and (if I
- read the C code correctly) it is not possible to observe a half-way
- mutated cons cell. The lookup procedure can handle this
- transparently without any critical sections.
-
- It is different with macro expansion, because macro expansion
- happens outside of the lookup procedure and can't be
- undone. Therefore the lookup procedure can't cope with it. It has
- to indicate failure when it detects a lost race and hope that the
- caller can handle it. Luckily, it turns out that this is the case.
-
- An example to illustrate this: Suppose that the following form will
- be memoized concurrently by two threads
-
- (let ((x 12)) x)
-
- Let's first examine the lookup of X in the body. The first thread
- decides that it has to find the symbol "x" in the environment and
- starts to scan it. Then the other thread takes over and actually
- overtakes the first. It looks up "x" and substitutes an
- appropriate iloc for it. Now the first thread continues and
- completes its lookup. It comes to exactly the same conclusions as
- the second one and could - without much ado - just overwrite the
- iloc with the same iloc.
-
- But let's see what will happen when the race occurs while looking
- up the symbol "let" at the start of the form. It could happen that
- the second thread interrupts the lookup of the first thread and not
- only substitutes a variable for it but goes right ahead and
- replaces it with the compiled form (#@let* (x 12) x). Now, when
- the first thread completes its lookup, it would replace the #@let*
- with a variable containing the "let" binding, effectively reverting
- the form to (let (x 12) x). This is wrong. It has to detect that
- it has lost the race and the evaluator has to reconsider the
- changed form completely.
-
- This race condition could be resolved with some kind of traffic
- light (like mutexes) around scm_lookupcar, but I think that it is
- best to avoid them in this case. They would serialize memoization
- completely and because lookup involves calling arbitrary Scheme
- code (via the lookup-thunk), threads could be blocked for an
- arbitrary amount of time or even deadlock. But with the current
- solution a lot of unnecessary work is potentially done. */
-
-/* SCM_LOOKUPCAR1 is what SCM_LOOKUPCAR used to be but is allowed to
- return NULL to indicate a failed lookup due to some race conditions
- between threads. This only happens when VLOC is the first cell of
- a special form that will eventually be memoized (like `let', etc.)
- In that case the whole lookup is bogus and the caller has to
- reconsider the complete special form.
-
- SCM_LOOKUPCAR is still there, of course. It just calls
- SCM_LOOKUPCAR1 and aborts on receiving NULL. So SCM_LOOKUPCAR
- should only be called when it is known that VLOC is not the first
- pair of a special form. Otherwise, use SCM_LOOKUPCAR1 and check
- for NULL. I think I've found the only places where this
- applies. */
-
-static SCM *
-scm_lookupcar1 (SCM vloc, SCM genv, int check)
-{
- SCM env = genv;
- register SCM *al, fl, var = SCM_CAR (vloc);
- register SCM iloc = SCM_ILOC00;
- for (; SCM_NIMP (env); env = SCM_CDR (env))
- {
- if (!scm_is_pair (SCM_CAR (env)))
- break;
- al = SCM_CARLOC (env);
- for (fl = SCM_CAR (*al); SCM_NIMP (fl); fl = SCM_CDR (fl))
- {
- if (!scm_is_pair (fl))
- {
- if (scm_is_eq (fl, var))
- {
- if (!scm_is_eq (SCM_CAR (vloc), var))
- goto race;
- SCM_SET_CELL_WORD_0 (vloc, SCM_UNPACK (iloc) + SCM_ICDR);
- return SCM_CDRLOC (*al);
- }
- else
- break;
- }
- al = SCM_CDRLOC (*al);
- if (scm_is_eq (SCM_CAR (fl), var))
- {
- if (SCM_UNBNDP (SCM_CAR (*al)))
- error_defined_variable (var);
- if (!scm_is_eq (SCM_CAR (vloc), var))
- goto race;
- SCM_SETCAR (vloc, iloc);
- return SCM_CARLOC (*al);
- }
- iloc = SCM_PACK (SCM_UNPACK (iloc) + SCM_IDINC);
- }
- iloc = SCM_PACK ((~SCM_IDSTMSK) & (SCM_UNPACK(iloc) + SCM_IFRINC));
- }
- {
- SCM top_thunk, real_var;
- if (SCM_NIMP (env))
- {
- top_thunk = SCM_CAR (env); /* env now refers to a
- top level env thunk */
- env = SCM_CDR (env);
- }
- else
- top_thunk = SCM_BOOL_F;
- real_var = scm_sym2var (var, top_thunk, SCM_BOOL_F);
- if (scm_is_false (real_var))
- goto errout;
-
- if (!scm_is_null (env) || SCM_UNBNDP (SCM_VARIABLE_REF (real_var)))
- {
- errout:
- if (check)
- {
- if (scm_is_null (env))
- error_unbound_variable (var);
- else
- scm_misc_error (NULL, "Damaged environment: ~S",
- scm_list_1 (var));
- }
- else
- {
- /* A variable could not be found, but we shall
- not throw an error. */
- static SCM undef_object = SCM_UNDEFINED;
- return &undef_object;
- }
- }
-
- if (!scm_is_eq (SCM_CAR (vloc), var))
- {
- /* Some other thread has changed the very cell we are working
- on. In effect, it must have done our job or messed it up
- completely. */
- race:
- var = SCM_CAR (vloc);
- if (SCM_VARIABLEP (var))
- return SCM_VARIABLE_LOC (var);
- if (SCM_ILOCP (var))
- return scm_ilookup (var, genv);
- /* We can't cope with anything else than variables and ilocs. When
- a special form has been memoized (i.e. `let' into `#@let') we
- return NULL and expect the calling function to do the right
- thing. For the evaluator, this means going back and redoing
- the dispatch on the car of the form. */
- return NULL;
- }
-
- SCM_SETCAR (vloc, real_var);
- return SCM_VARIABLE_LOC (real_var);
- }
-}
-
-SCM *
-scm_lookupcar (SCM vloc, SCM genv, int check)
-{
- SCM *loc = scm_lookupcar1 (vloc, genv, check);
- if (loc == NULL)
- abort ();
- return loc;
-}
-
-
-/* During execution, look up a symbol in the top level of the given local
- * environment and return the corresponding variable object. If no binding
- * for the symbol can be found, an 'Unbound variable' error is signalled. */
-static SCM
-lazy_memoize_variable (const SCM symbol, const SCM environment)
-{
- const SCM top_level = scm_env_top_level (environment);
- const SCM variable = scm_sym2var (symbol, top_level, SCM_BOOL_F);
-
- if (scm_is_false (variable))
- error_unbound_variable (symbol);
- else
- return variable;
-}
-
-
-SCM
-scm_eval_car (SCM pair, SCM env)
-{
- return SCM_I_XEVALCAR (pair, env, scm_debug_mode_p);
-}
-
-
-SCM
-scm_eval_body (SCM code, SCM env)
-{
- SCM next;
-
- again:
- next = SCM_CDR (code);
- while (!scm_is_null (next))
- {
- if (SCM_IMP (SCM_CAR (code)))
- {
- if (SCM_ISYMP (SCM_CAR (code)))
- {
- scm_dynwind_begin (0);
- scm_i_dynwind_pthread_mutex_lock (&source_mutex);
- /* check for race condition */
- if (SCM_ISYMP (SCM_CAR (code)))
- m_expand_body (code, env);
- scm_dynwind_end ();
- goto again;
- }
- }
- else
- SCM_I_XEVAL (SCM_CAR (code), env, scm_debug_mode_p);
- code = next;
- next = SCM_CDR (code);
- }
- return SCM_I_XEVALCAR (code, env, scm_debug_mode_p);
-}
-
-
-/* scm_last_debug_frame contains a pointer to the last debugging information
- * stack frame. It is accessed very often from the debugging evaluator, so it
- * should probably not be indirectly addressed. Better to save and restore it
- * from the current root at any stack swaps.
- */
-
-/* scm_debug_eframe_size is the number of slots available for pseudo
- * stack frames at each real stack frame.
- */
-
-long scm_debug_eframe_size;
-
-int scm_debug_mode_p;
-int scm_check_entry_p;
-int scm_check_apply_p;
-int scm_check_exit_p;
-int scm_check_memoize_p;
-
-long scm_eval_stack;
-
-scm_t_option scm_eval_opts[] = {
- { SCM_OPTION_INTEGER, "stack", 22000, "Size of thread stacks (in machine words)." },
- { 0 }
-};
-
-scm_t_option scm_debug_opts[] = {
- { SCM_OPTION_BOOLEAN, "cheap", 1,
- "*This option is now obsolete. Setting it has no effect." },
- { SCM_OPTION_BOOLEAN, "breakpoints", 0, "*Check for breakpoints." },
- { SCM_OPTION_BOOLEAN, "trace", 0, "*Trace mode." },
- { SCM_OPTION_BOOLEAN, "procnames", 1,
- "Record procedure names at definition." },
- { SCM_OPTION_BOOLEAN, "backwards", 0,
- "Display backtrace in anti-chronological order." },
- { SCM_OPTION_INTEGER, "width", 79, "Maximal width of backtrace." },
- { SCM_OPTION_INTEGER, "indent", 10, "Maximal indentation in backtrace." },
- { SCM_OPTION_INTEGER, "frames", 3,
- "Maximum number of tail-recursive frames in backtrace." },
- { SCM_OPTION_INTEGER, "maxdepth", 1000,
- "Maximal number of stored backtrace frames." },
- { SCM_OPTION_INTEGER, "depth", 20, "Maximal length of printed backtrace." },
- { SCM_OPTION_BOOLEAN, "backtrace", 0, "Show backtrace on error." },
- { SCM_OPTION_BOOLEAN, "debug", 0, "Use the debugging evaluator." },
-
- { SCM_OPTION_INTEGER, "stack", 20000, "Stack size limit (measured in words; 0 = no check)." },
- { SCM_OPTION_SCM, "show-file-name", (unsigned long)SCM_BOOL_T,
- "Show file names and line numbers "
- "in backtraces when not `#f'. A value of `base' "
- "displays only base names, while `#t' displays full names."},
- { SCM_OPTION_BOOLEAN, "warn-deprecated", 0,
- "Warn when deprecated features are used." },
- { 0 },
-};
-
-
-/*
- * this ordering is awkward and illogical, but we maintain it for
- * compatibility. --hwn
- */
-scm_t_option scm_evaluator_trap_table[] = {
- { SCM_OPTION_BOOLEAN, "traps", 0, "Enable evaluator traps." },
- { SCM_OPTION_BOOLEAN, "enter-frame", 0, "Trap when eval enters new frame." },
- { SCM_OPTION_BOOLEAN, "apply-frame", 0, "Trap when entering apply." },
- { SCM_OPTION_BOOLEAN, "exit-frame", 0, "Trap when exiting eval or apply." },
- { SCM_OPTION_SCM, "enter-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for enter-frame traps." },
- { SCM_OPTION_SCM, "apply-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for apply-frame traps." },
- { SCM_OPTION_SCM, "exit-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for exit-frame traps." },
- { SCM_OPTION_BOOLEAN, "memoize-symbol", 0, "Trap when memoizing a symbol." },
- { SCM_OPTION_SCM, "memoize-symbol-handler", (unsigned long)SCM_BOOL_F, "The handler for memoization." },
- { 0 }
-};
-
-
-SCM_DEFINE (scm_eval_options_interface, "eval-options-interface", 0, 1, 0,
- (SCM setting),
- "Option interface for the evaluation options. Instead of using\n"
- "this procedure directly, use the procedures @code{eval-enable},\n"
- "@code{eval-disable}, @code{eval-set!} and @code{eval-options}.")
-#define FUNC_NAME s_scm_eval_options_interface
-{
- SCM ans;
-
- scm_dynwind_begin (0);
- scm_dynwind_critical_section (SCM_BOOL_F);
- ans = scm_options (setting,
- scm_eval_opts,
- FUNC_NAME);
- scm_eval_stack = SCM_EVAL_STACK * sizeof (void *);
- scm_dynwind_end ();
-
- return ans;
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_evaluator_traps, "evaluator-traps-interface", 0, 1, 0,
- (SCM setting),
- "Option interface for the evaluator trap options.")
-#define FUNC_NAME s_scm_evaluator_traps
-{
- SCM ans;
-
-
- scm_options_try (setting,
- scm_evaluator_trap_table,
- FUNC_NAME, 1);
- SCM_CRITICAL_SECTION_START;
- ans = scm_options (setting,
- scm_evaluator_trap_table,
- FUNC_NAME);
-
- /* njrev: same again. */
- SCM_RESET_DEBUG_MODE;
- SCM_CRITICAL_SECTION_END;
- return ans;
-}
-#undef FUNC_NAME
-
-
-
-\f
-
-/* Simple procedure calls
- */
-
-SCM
-scm_call_0 (SCM proc)
-{
- return scm_apply (proc, SCM_EOL, SCM_EOL);
-}
-
-SCM
-scm_call_1 (SCM proc, SCM arg1)
-{
- return scm_apply (proc, arg1, scm_listofnull);
-}
-
-SCM
-scm_call_2 (SCM proc, SCM arg1, SCM arg2)
-{
- return scm_apply (proc, arg1, scm_cons (arg2, scm_listofnull));
-}
-
-SCM
-scm_call_3 (SCM proc, SCM arg1, SCM arg2, SCM arg3)
-{
- return scm_apply (proc, arg1, scm_cons2 (arg2, arg3, scm_listofnull));
-}
-
-SCM
-scm_call_4 (SCM proc, SCM arg1, SCM arg2, SCM arg3, SCM arg4)
-{
- return scm_apply (proc, arg1, scm_cons2 (arg2, arg3,
- scm_cons (arg4, scm_listofnull)));
-}
-
-/* Simple procedure applies
- */
-
-SCM
-scm_apply_0 (SCM proc, SCM args)
-{
- return scm_apply (proc, args, SCM_EOL);
-}
-
-SCM
-scm_apply_1 (SCM proc, SCM arg1, SCM args)
-{
- return scm_apply (proc, scm_cons (arg1, args), SCM_EOL);
-}
-
-SCM
-scm_apply_2 (SCM proc, SCM arg1, SCM arg2, SCM args)
-{
- return scm_apply (proc, scm_cons2 (arg1, arg2, args), SCM_EOL);
-}
-
-SCM
-scm_apply_3 (SCM proc, SCM arg1, SCM arg2, SCM arg3, SCM args)
-{
- return scm_apply (proc, scm_cons (arg1, scm_cons2 (arg2, arg3, args)),
- SCM_EOL);
-}
-
-/* This code processes the arguments to apply:
-
- (apply PROC ARG1 ... ARGS)
-
- Given a list (ARG1 ... ARGS), this function conses the ARG1
- ... arguments onto the front of ARGS, and returns the resulting
- list. Note that ARGS is a list; thus, the argument to this
- function is a list whose last element is a list.
-
- Apply calls this function, and applies PROC to the elements of the
- result. apply:nconc2last takes care of building the list of
- arguments, given (ARG1 ... ARGS).
-
- Rather than do new consing, apply:nconc2last destroys its argument.
- On that topic, this code came into my care with the following
- beautifully cryptic comment on that topic: "This will only screw
- you if you do (scm_apply scm_apply '( ... ))" If you know what
- they're referring to, send me a patch to this comment. */
-
-SCM_DEFINE (scm_nconc2last, "apply:nconc2last", 1, 0, 0,
- (SCM lst),
- "Given a list (@var{arg1} @dots{} @var{args}), this function\n"
- "conses the @var{arg1} @dots{} arguments onto the front of\n"
- "@var{args}, and returns the resulting list. Note that\n"
- "@var{args} is a list; thus, the argument to this function is\n"
- "a list whose last element is a list.\n"
- "Note: Rather than do new consing, @code{apply:nconc2last}\n"
- "destroys its argument, so use with care.")
-#define FUNC_NAME s_scm_nconc2last
-{
- SCM *lloc;
- SCM_VALIDATE_NONEMPTYLIST (1, lst);
- lloc = &lst;
- while (!scm_is_null (SCM_CDR (*lloc))) /* Perhaps should be
- SCM_NULL_OR_NIL_P, but not
- needed in 99.99% of cases,
- and it could seriously hurt
- performance. - Neil */
- lloc = SCM_CDRLOC (*lloc);
- SCM_ASSERT (scm_ilength (SCM_CAR (*lloc)) >= 0, lst, SCM_ARG1, FUNC_NAME);
- *lloc = SCM_CAR (*lloc);
- return lst;
-}
-#undef FUNC_NAME
-
-
-
-/* SECTION: The rest of this file is only read once.
- */
-
-/* Trampolines
- *
- * Trampolines make it possible to move procedure application dispatch
- * outside inner loops. The motivation was clean implementation of
- * efficient replacements of R5RS primitives in SRFI-1.
- *
- * The semantics is clear: scm_trampoline_N returns an optimized
- * version of scm_call_N (or NULL if the procedure isn't applicable
- * on N args).
- *
- * Applying the optimization to map and for-each increased efficiency
- * noticeably. For example, (map abs ls) is now 8 times faster than
- * before.
- */
-
-static SCM
-call_subr0_0 (SCM proc)
-{
- return SCM_SUBRF (proc) ();
-}
-
-static SCM
-call_subr1o_0 (SCM proc)
-{
- return SCM_SUBRF (proc) (SCM_UNDEFINED);
-}
-
-static SCM
-call_lsubr_0 (SCM proc)
-{
- return SCM_SUBRF (proc) (SCM_EOL);
-}
-
-SCM
-scm_i_call_closure_0 (SCM proc)
-{
- const SCM env = SCM_EXTEND_ENV (SCM_CLOSURE_FORMALS (proc),
- SCM_EOL,
- SCM_ENV (proc));
- const SCM result = scm_eval_body (SCM_CLOSURE_BODY (proc), env);
- return result;
-}
-
-scm_t_trampoline_0
-scm_trampoline_0 (SCM proc)
-{
- scm_t_trampoline_0 trampoline;
-
- if (SCM_IMP (proc))
- return NULL;
-
- switch (SCM_TYP7 (proc))
- {
- case scm_tc7_subr_0:
- trampoline = call_subr0_0;
- break;
- case scm_tc7_subr_1o:
- trampoline = call_subr1o_0;
- break;
- case scm_tc7_lsubr:
- trampoline = call_lsubr_0;
- break;
- case scm_tcs_closures:
- {
- SCM formals = SCM_CLOSURE_FORMALS (proc);
- if (scm_is_null (formals) || !scm_is_pair (formals))
- trampoline = scm_i_call_closure_0;
- else
- return NULL;
- break;
- }
- case scm_tcs_struct:
- if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
- trampoline = scm_call_generic_0;
- else if (SCM_I_OPERATORP (proc))
- trampoline = scm_call_0;
- else
- return NULL;
- break;
- case scm_tc7_smob:
- if (SCM_SMOB_APPLICABLE_P (proc))
- trampoline = SCM_SMOB_DESCRIPTOR (proc).apply_0;
- else
- return NULL;
- break;
- case scm_tc7_asubr:
- case scm_tc7_rpsubr:
- case scm_tc7_cclo:
- case scm_tc7_pws:
- trampoline = scm_call_0;
- break;
- default:
- return NULL; /* not applicable on zero arguments */
- }
- /* We only reach this point if a valid trampoline was determined. */
-
- /* If debugging is enabled, we want to see all calls to proc on the stack.
- * Thus, we replace the trampoline shortcut with scm_call_0. */
- if (scm_debug_mode_p)
- return scm_call_0;
- else
- return trampoline;
-}
-
-static SCM
-call_subr1_1 (SCM proc, SCM arg1)
-{
- return SCM_SUBRF (proc) (arg1);
-}
-
-static SCM
-call_subr2o_1 (SCM proc, SCM arg1)
-{
- return SCM_SUBRF (proc) (arg1, SCM_UNDEFINED);
-}
-
-static SCM
-call_lsubr_1 (SCM proc, SCM arg1)
-{
- return SCM_SUBRF (proc) (scm_list_1 (arg1));
-}
-
-static SCM
-call_dsubr_1 (SCM proc, SCM arg1)
-{
- if (SCM_I_INUMP (arg1))
- {
- return (scm_from_double (SCM_DSUBRF (proc) ((double) SCM_I_INUM (arg1))));
- }
- else if (SCM_REALP (arg1))
- {
- return (scm_from_double (SCM_DSUBRF (proc) (SCM_REAL_VALUE (arg1))));
- }
- else if (SCM_BIGP (arg1))
- {
- return (scm_from_double (SCM_DSUBRF (proc) (scm_i_big2dbl (arg1))));
- }
- else if (SCM_FRACTIONP (arg1))
- {
- return (scm_from_double (SCM_DSUBRF (proc) (scm_i_fraction2double (arg1))));
- }
- SCM_WTA_DISPATCH_1 (*SCM_SUBR_GENERIC (proc), arg1,
- SCM_ARG1, scm_i_symbol_chars (SCM_SNAME (proc)));
-}
-
-static SCM
-call_cxr_1 (SCM proc, SCM arg1)
-{
- return scm_i_chase_pairs (arg1, (scm_t_bits) SCM_SUBRF (proc));
-}
-
-static SCM
-call_closure_1 (SCM proc, SCM arg1)
-{
- const SCM env = SCM_EXTEND_ENV (SCM_CLOSURE_FORMALS (proc),
- scm_list_1 (arg1),
- SCM_ENV (proc));
- const SCM result = scm_eval_body (SCM_CLOSURE_BODY (proc), env);
- return result;
-}
-
-scm_t_trampoline_1
-scm_trampoline_1 (SCM proc)
-{
- scm_t_trampoline_1 trampoline;
-
- if (SCM_IMP (proc))
- return NULL;
-
- switch (SCM_TYP7 (proc))
- {
- case scm_tc7_subr_1:
- case scm_tc7_subr_1o:
- trampoline = call_subr1_1;
- break;
- case scm_tc7_subr_2o:
- trampoline = call_subr2o_1;
- break;
- case scm_tc7_lsubr:
- trampoline = call_lsubr_1;
- break;
- case scm_tc7_dsubr:
- trampoline = call_dsubr_1;
- break;
- case scm_tc7_cxr:
- trampoline = call_cxr_1;
- break;
- case scm_tcs_closures:
- {
- SCM formals = SCM_CLOSURE_FORMALS (proc);
- if (!scm_is_null (formals)
- && (!scm_is_pair (formals) || !scm_is_pair (SCM_CDR (formals))))
- trampoline = call_closure_1;
- else
- return NULL;
- break;
- }
- case scm_tcs_struct:
- if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
- trampoline = scm_call_generic_1;
- else if (SCM_I_OPERATORP (proc))
- trampoline = scm_call_1;
- else
- return NULL;
- break;
- case scm_tc7_smob:
- if (SCM_SMOB_APPLICABLE_P (proc))
- trampoline = SCM_SMOB_DESCRIPTOR (proc).apply_1;
- else
- return NULL;
- break;
- case scm_tc7_asubr:
- case scm_tc7_rpsubr:
- case scm_tc7_cclo:
- case scm_tc7_pws:
- trampoline = scm_call_1;
- break;
- default:
- return NULL; /* not applicable on one arg */
- }
- /* We only reach this point if a valid trampoline was determined. */
-
- /* If debugging is enabled, we want to see all calls to proc on the stack.
- * Thus, we replace the trampoline shortcut with scm_call_1. */
- if (scm_debug_mode_p)
- return scm_call_1;
- else
- return trampoline;
-}
-
-static SCM
-call_subr2_2 (SCM proc, SCM arg1, SCM arg2)
-{
- return SCM_SUBRF (proc) (arg1, arg2);
-}
-
-static SCM
-call_lsubr2_2 (SCM proc, SCM arg1, SCM arg2)
-{
- return SCM_SUBRF (proc) (arg1, arg2, SCM_EOL);
-}
-
-static SCM
-call_lsubr_2 (SCM proc, SCM arg1, SCM arg2)
-{
- return SCM_SUBRF (proc) (scm_list_2 (arg1, arg2));
-}
-
-static SCM
-call_closure_2 (SCM proc, SCM arg1, SCM arg2)
-{
- const SCM env = SCM_EXTEND_ENV (SCM_CLOSURE_FORMALS (proc),
- scm_list_2 (arg1, arg2),
- SCM_ENV (proc));
- const SCM result = scm_eval_body (SCM_CLOSURE_BODY (proc), env);
- return result;
-}
-
-scm_t_trampoline_2
-scm_trampoline_2 (SCM proc)
-{
- scm_t_trampoline_2 trampoline;
-
- if (SCM_IMP (proc))
- return NULL;
-
- switch (SCM_TYP7 (proc))
- {
- case scm_tc7_subr_2:
- case scm_tc7_subr_2o:
- case scm_tc7_rpsubr:
- case scm_tc7_asubr:
- trampoline = call_subr2_2;
- break;
- case scm_tc7_lsubr_2:
- trampoline = call_lsubr2_2;
- break;
- case scm_tc7_lsubr:
- trampoline = call_lsubr_2;
- break;
- case scm_tcs_closures:
- {
- SCM formals = SCM_CLOSURE_FORMALS (proc);
- if (!scm_is_null (formals)
- && (!scm_is_pair (formals)
- || (!scm_is_null (SCM_CDR (formals))
- && (!scm_is_pair (SCM_CDR (formals))
- || !scm_is_pair (SCM_CDDR (formals))))))
- trampoline = call_closure_2;
- else
- return NULL;
- break;
- }
- case scm_tcs_struct:
- if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
- trampoline = scm_call_generic_2;
- else if (SCM_I_OPERATORP (proc))
- trampoline = scm_call_2;
- else
- return NULL;
- break;
- case scm_tc7_smob:
- if (SCM_SMOB_APPLICABLE_P (proc))
- trampoline = SCM_SMOB_DESCRIPTOR (proc).apply_2;
- else
- return NULL;
- break;
- case scm_tc7_cclo:
- case scm_tc7_pws:
- trampoline = scm_call_2;
- break;
- default:
- return NULL; /* not applicable on two args */
- }
- /* We only reach this point if a valid trampoline was determined. */
-
- /* If debugging is enabled, we want to see all calls to proc on the stack.
- * Thus, we replace the trampoline shortcut with scm_call_2. */
- if (scm_debug_mode_p)
- return scm_call_2;
- else
- return trampoline;
-}
-
-/* Typechecking for multi-argument MAP and FOR-EACH.
-
- Verify that each element of the vector ARGV, except for the first,
- is a proper list whose length is LEN. Attribute errors to WHO,
- and claim that the i'th element of ARGV is WHO's i+2'th argument. */
-static inline void
-check_map_args (SCM argv,
- long len,
- SCM gf,
- SCM proc,
- SCM args,
- const char *who)
-{
- long i;
-
- for (i = SCM_SIMPLE_VECTOR_LENGTH (argv) - 1; i >= 1; i--)
- {
- SCM elt = SCM_SIMPLE_VECTOR_REF (argv, i);
- long elt_len = scm_ilength (elt);
-
- if (elt_len < 0)
- {
- if (gf)
- scm_apply_generic (gf, scm_cons (proc, args));
- else
- scm_wrong_type_arg (who, i + 2, elt);
- }
-
- if (elt_len != len)
- scm_out_of_range_pos (who, elt, scm_from_long (i + 2));
- }
-}
-
-
-SCM_GPROC (s_map, "map", 2, 0, 1, scm_map, g_map);
-
-/* Note: Currently, scm_map applies PROC to the argument list(s)
- sequentially, starting with the first element(s). This is used in
- evalext.c where the Scheme procedure `map-in-order', which guarantees
- sequential behaviour, is implemented using scm_map. If the
- behaviour changes, we need to update `map-in-order'.
-*/
-
-SCM
-scm_map (SCM proc, SCM arg1, SCM args)
-#define FUNC_NAME s_map
-{
- long i, len;
- SCM res = SCM_EOL;
- SCM *pres = &res;
-
- len = scm_ilength (arg1);
- SCM_GASSERTn (len >= 0,
- g_map, scm_cons2 (proc, arg1, args), SCM_ARG2, s_map);
- SCM_VALIDATE_REST_ARGUMENT (args);
- if (scm_is_null (args))
- {
- scm_t_trampoline_1 call = scm_trampoline_1 (proc);
- SCM_GASSERT2 (call, g_map, proc, arg1, SCM_ARG1, s_map);
- while (SCM_NIMP (arg1))
- {
- *pres = scm_list_1 (call (proc, SCM_CAR (arg1)));
- pres = SCM_CDRLOC (*pres);
- arg1 = SCM_CDR (arg1);
- }
- return res;
- }
- if (scm_is_null (SCM_CDR (args)))
- {
- SCM arg2 = SCM_CAR (args);
- int len2 = scm_ilength (arg2);
- scm_t_trampoline_2 call = scm_trampoline_2 (proc);
- SCM_GASSERTn (call,
- g_map, scm_cons2 (proc, arg1, args), SCM_ARG1, s_map);
- SCM_GASSERTn (len2 >= 0,
- g_map, scm_cons2 (proc, arg1, args), SCM_ARG3, s_map);
- if (len2 != len)
- SCM_OUT_OF_RANGE (3, arg2);
- while (SCM_NIMP (arg1))
- {
- *pres = scm_list_1 (call (proc, SCM_CAR (arg1), SCM_CAR (arg2)));
- pres = SCM_CDRLOC (*pres);
- arg1 = SCM_CDR (arg1);
- arg2 = SCM_CDR (arg2);
- }
- return res;
- }
- arg1 = scm_cons (arg1, args);
- args = scm_vector (arg1);
- check_map_args (args, len, g_map, proc, arg1, s_map);
- while (1)
- {
- arg1 = SCM_EOL;
- for (i = SCM_SIMPLE_VECTOR_LENGTH (args) - 1; i >= 0; i--)
- {
- SCM elt = SCM_SIMPLE_VECTOR_REF (args, i);
- if (SCM_IMP (elt))
- return res;
- arg1 = scm_cons (SCM_CAR (elt), arg1);
- SCM_SIMPLE_VECTOR_SET (args, i, SCM_CDR (elt));
- }
- *pres = scm_list_1 (scm_apply (proc, arg1, SCM_EOL));
- pres = SCM_CDRLOC (*pres);
- }
-}
-#undef FUNC_NAME
-
-
-SCM_GPROC (s_for_each, "for-each", 2, 0, 1, scm_for_each, g_for_each);
-
-SCM
-scm_for_each (SCM proc, SCM arg1, SCM args)
-#define FUNC_NAME s_for_each
-{
- long i, len;
- len = scm_ilength (arg1);
- SCM_GASSERTn (len >= 0, g_for_each, scm_cons2 (proc, arg1, args),
- SCM_ARG2, s_for_each);
- SCM_VALIDATE_REST_ARGUMENT (args);
- if (scm_is_null (args))
- {
- scm_t_trampoline_1 call = scm_trampoline_1 (proc);
- SCM_GASSERT2 (call, g_for_each, proc, arg1, SCM_ARG1, s_for_each);
- while (SCM_NIMP (arg1))
- {
- call (proc, SCM_CAR (arg1));
- arg1 = SCM_CDR (arg1);
- }
- return SCM_UNSPECIFIED;
- }
- if (scm_is_null (SCM_CDR (args)))
- {
- SCM arg2 = SCM_CAR (args);
- int len2 = scm_ilength (arg2);
- scm_t_trampoline_2 call = scm_trampoline_2 (proc);
- SCM_GASSERTn (call, g_for_each,
- scm_cons2 (proc, arg1, args), SCM_ARG1, s_for_each);
- SCM_GASSERTn (len2 >= 0, g_for_each,
- scm_cons2 (proc, arg1, args), SCM_ARG3, s_for_each);
- if (len2 != len)
- SCM_OUT_OF_RANGE (3, arg2);
- while (SCM_NIMP (arg1))
- {
- call (proc, SCM_CAR (arg1), SCM_CAR (arg2));
- arg1 = SCM_CDR (arg1);
- arg2 = SCM_CDR (arg2);
- }
- return SCM_UNSPECIFIED;
- }
- arg1 = scm_cons (arg1, args);
- args = scm_vector (arg1);
- check_map_args (args, len, g_for_each, proc, arg1, s_for_each);
- while (1)
- {
- arg1 = SCM_EOL;
- for (i = SCM_SIMPLE_VECTOR_LENGTH (args) - 1; i >= 0; i--)
- {
- SCM elt = SCM_SIMPLE_VECTOR_REF (args, i);
- if (SCM_IMP (elt))
- return SCM_UNSPECIFIED;
- arg1 = scm_cons (SCM_CAR (elt), arg1);
- SCM_SIMPLE_VECTOR_SET (args, i, SCM_CDR (elt));
- }
- scm_apply (proc, arg1, SCM_EOL);
- }
-}
-#undef FUNC_NAME
-
-
-SCM
-scm_closure (SCM code, SCM env)
-{
- SCM z;
- SCM closcar = scm_cons (code, SCM_EOL);
- z = scm_cell (SCM_UNPACK (closcar) + scm_tc3_closure, (scm_t_bits) env);
- scm_remember_upto_here (closcar);
- return z;
-}
-
-
-scm_t_bits scm_tc16_promise;
-
-SCM
-scm_makprom (SCM code)
-{
- SCM_RETURN_NEWSMOB2 (scm_tc16_promise,
- SCM_UNPACK (code),
- scm_make_recursive_mutex ());
-}
-
-static SCM
-promise_mark (SCM promise)
-{
- scm_gc_mark (SCM_PROMISE_MUTEX (promise));
- return SCM_PROMISE_DATA (promise);
-}
-
-static size_t
-promise_free (SCM promise)
-{
- return 0;
-}
-
-static int
-promise_print (SCM exp, SCM port, scm_print_state *pstate)
-{
- int writingp = SCM_WRITINGP (pstate);
- scm_puts ("#<promise ", port);
- SCM_SET_WRITINGP (pstate, 1);
- scm_iprin1 (SCM_PROMISE_DATA (exp), port, pstate);
- SCM_SET_WRITINGP (pstate, writingp);
- scm_putc ('>', port);
- return !0;
-}
-
-SCM_DEFINE (scm_force, "force", 1, 0, 0,
- (SCM promise),
- "If the promise @var{x} has not been computed yet, compute and\n"
- "return @var{x}, otherwise just return the previously computed\n"
- "value.")
-#define FUNC_NAME s_scm_force
-{
- SCM_VALIDATE_SMOB (1, promise, promise);
- scm_lock_mutex (SCM_PROMISE_MUTEX (promise));
- if (!SCM_PROMISE_COMPUTED_P (promise))
- {
- SCM ans = scm_call_0 (SCM_PROMISE_DATA (promise));
- if (!SCM_PROMISE_COMPUTED_P (promise))
- {
- SCM_SET_PROMISE_DATA (promise, ans);
- SCM_SET_PROMISE_COMPUTED (promise);
- }
- }
- scm_unlock_mutex (SCM_PROMISE_MUTEX (promise));
- return SCM_PROMISE_DATA (promise);
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_promise_p, "promise?", 1, 0, 0,
- (SCM obj),
- "Return true if @var{obj} is a promise, i.e. a delayed computation\n"
- "(@pxref{Delayed evaluation,,,r5rs.info,The Revised^5 Report on Scheme}).")
-#define FUNC_NAME s_scm_promise_p
-{
- return scm_from_bool (SCM_TYP16_PREDICATE (scm_tc16_promise, obj));
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_cons_source, "cons-source", 3, 0, 0,
- (SCM xorig, SCM x, SCM y),
- "Create and return a new pair whose car and cdr are @var{x} and @var{y}.\n"
- "Any source properties associated with @var{xorig} are also associated\n"
- "with the new pair.")
-#define FUNC_NAME s_scm_cons_source
-{
- SCM p, z;
- z = scm_cons (x, y);
- /* Copy source properties possibly associated with xorig. */
- p = scm_whash_lookup (scm_source_whash, xorig);
- if (scm_is_true (p))
- scm_whash_insert (scm_source_whash, z, p);
- return z;
-}
-#undef FUNC_NAME
-
-
-/* The function scm_copy_tree is used to copy an expression tree to allow the
- * memoizer to modify the expression during memoization. scm_copy_tree
- * creates deep copies of pairs and vectors, but not of any other data types,
- * since only pairs and vectors will be parsed by the memoizer.
- *
- * To avoid infinite recursion due to cyclic structures, the hare-and-tortoise
- * pattern is used to detect cycles. In fact, the pattern is used in two
- * dimensions, vertical (indicated in the code by the variable names 'hare'
- * and 'tortoise') and horizontal ('rabbit' and 'turtle'). In both
- * dimensions, the hare/rabbit will take two steps when the tortoise/turtle
- * takes one.
- *
- * The vertical dimension corresponds to recursive calls to function
- * copy_tree: This happens when descending into vector elements, into cars of
- * lists and into the cdr of an improper list. In this dimension, the
- * tortoise follows the hare by using the processor stack: Every stack frame
- * will hold an instance of struct t_trace. These instances are connected in
- * a way that represents the trace of the hare, which thus can be followed by
- * the tortoise. The tortoise will always point to struct t_trace instances
- * relating to SCM objects that have already been copied. Thus, a cycle is
- * detected if the tortoise and the hare point to the same object,
- *
- * The horizontal dimension is within one execution of copy_tree, when the
- * function cdr's along the pairs of a list. This is the standard
- * hare-and-tortoise implementation, found several times in guile. */
-
-struct t_trace {
- struct t_trace *trace; /* These pointers form a trace along the stack. */
- SCM obj; /* The object handled at the respective stack frame.*/
-};
-
-static SCM
-copy_tree (
- struct t_trace *const hare,
- struct t_trace *tortoise,
- unsigned int tortoise_delay )
-{
- if (!scm_is_pair (hare->obj) && !scm_is_simple_vector (hare->obj))
- {
- return hare->obj;
- }
- else
- {
- /* Prepare the trace along the stack. */
- struct t_trace new_hare;
- hare->trace = &new_hare;
-
- /* The tortoise will make its step after the delay has elapsed. Note
- * that in contrast to the typical hare-and-tortoise pattern, the step
- * of the tortoise happens before the hare takes its steps. This is, in
- * principle, no problem, except for the start of the algorithm: Then,
- * it has to be made sure that the hare actually gets its advantage of
- * two steps. */
- if (tortoise_delay == 0)
- {
- tortoise_delay = 1;
- tortoise = tortoise->trace;
- ASSERT_SYNTAX (!scm_is_eq (hare->obj, tortoise->obj),
- s_bad_expression, hare->obj);
- }
- else
- {
- --tortoise_delay;
- }
-
- if (scm_is_simple_vector (hare->obj))
- {
- size_t length = SCM_SIMPLE_VECTOR_LENGTH (hare->obj);
- SCM new_vector = scm_c_make_vector (length, SCM_UNSPECIFIED);
-
- /* Each vector element is copied by recursing into copy_tree, having
- * the tortoise follow the hare into the depths of the stack. */
- unsigned long int i;
- for (i = 0; i < length; ++i)
- {
- SCM new_element;
- new_hare.obj = SCM_SIMPLE_VECTOR_REF (hare->obj, i);
- new_element = copy_tree (&new_hare, tortoise, tortoise_delay);
- SCM_SIMPLE_VECTOR_SET (new_vector, i, new_element);
- }
-
- return new_vector;
- }
- else /* scm_is_pair (hare->obj) */
- {
- SCM result;
- SCM tail;
-
- SCM rabbit = hare->obj;
- SCM turtle = hare->obj;
-
- SCM copy;
-
- /* The first pair of the list is treated specially, in order to
- * preserve a potential source code position. */
- result = tail = scm_cons_source (rabbit, SCM_EOL, SCM_EOL);
- new_hare.obj = SCM_CAR (rabbit);
- copy = copy_tree (&new_hare, tortoise, tortoise_delay);
- SCM_SETCAR (tail, copy);
-
- /* The remaining pairs of the list are copied by, horizontally,
- * having the turtle follow the rabbit, and, vertically, having the
- * tortoise follow the hare into the depths of the stack. */
- rabbit = SCM_CDR (rabbit);
- while (scm_is_pair (rabbit))
- {
- new_hare.obj = SCM_CAR (rabbit);
- copy = copy_tree (&new_hare, tortoise, tortoise_delay);
- SCM_SETCDR (tail, scm_cons (copy, SCM_UNDEFINED));
- tail = SCM_CDR (tail);
-
- rabbit = SCM_CDR (rabbit);
- if (scm_is_pair (rabbit))
- {
- new_hare.obj = SCM_CAR (rabbit);
- copy = copy_tree (&new_hare, tortoise, tortoise_delay);
- SCM_SETCDR (tail, scm_cons (copy, SCM_UNDEFINED));
- tail = SCM_CDR (tail);
- rabbit = SCM_CDR (rabbit);
-
- turtle = SCM_CDR (turtle);
- ASSERT_SYNTAX (!scm_is_eq (rabbit, turtle),
- s_bad_expression, rabbit);
- }
- }
-
- /* We have to recurse into copy_tree again for the last cdr, in
- * order to handle the situation that it holds a vector. */
- new_hare.obj = rabbit;
- copy = copy_tree (&new_hare, tortoise, tortoise_delay);
- SCM_SETCDR (tail, copy);
-
- return result;
- }
- }
-}
-
-SCM_DEFINE (scm_copy_tree, "copy-tree", 1, 0, 0,
- (SCM obj),
- "Recursively copy the data tree that is bound to @var{obj}, and return a\n"
- "the new data structure. @code{copy-tree} recurses down the\n"
- "contents of both pairs and vectors (since both cons cells and vector\n"
- "cells may point to arbitrary objects), and stops recursing when it hits\n"
- "any other object.")
-#define FUNC_NAME s_scm_copy_tree
-{
- /* Prepare the trace along the stack. */
- struct t_trace trace;
- trace.obj = obj;
-
- /* In function copy_tree, if the tortoise makes its step, it will do this
- * before the hare has the chance to move. Thus, we have to make sure that
- * the very first step of the tortoise will not happen after the hare has
- * really made two steps. This is achieved by passing '2' as the initial
- * delay for the tortoise. NOTE: Since cycles are unlikely, giving the hare
- * a bigger advantage may improve performance slightly. */
- return copy_tree (&trace, &trace, 2);
-}
-#undef FUNC_NAME
-
-
-/* We have three levels of EVAL here:
-
- - scm_i_eval (exp, env)
-
- evaluates EXP in environment ENV. ENV is a lexical environment
- structure as used by the actual tree code evaluator. When ENV is
- a top-level environment, then changes to the current module are
- tracked by updating ENV so that it continues to be in sync with
- the current module.
-
- - scm_primitive_eval (exp)
-
- evaluates EXP in the top-level environment as determined by the
- current module. This is done by constructing a suitable
- environment and calling scm_i_eval. Thus, changes to the
- top-level module are tracked normally.
-
- - scm_eval (exp, mod_or_state)
-
- evaluates EXP while MOD_OR_STATE is the current module or current
- dynamic state (as appropriate). This is done by setting the
- current module (or dynamic state) to MOD_OR_STATE, invoking
- scm_primitive_eval on EXP, and then restoring the current module
- (or dynamic state) to the value it had previously. That is,
- while EXP is evaluated, changes to the current module (or dynamic
- state) are tracked, but these changes do not persist when
- scm_eval returns.
-
- For each level of evals, there are two variants, distinguished by a
- _x suffix: the ordinary variant does not modify EXP while the _x
- variant can destructively modify EXP into something completely
- unintelligible. A Scheme data structure passed as EXP to one of the
- _x variants should not ever be used again for anything. So when in
- doubt, use the ordinary variant.
-
-*/
-
-SCM
-scm_i_eval_x (SCM exp, SCM env)
-{
- if (scm_is_symbol (exp))
- return *scm_lookupcar (scm_cons (exp, SCM_UNDEFINED), env, 1);
- else
- return SCM_I_XEVAL (exp, env, scm_debug_mode_p);
-}
-
-SCM
-scm_i_eval (SCM exp, SCM env)
-{
- exp = scm_copy_tree (exp);
- if (scm_is_symbol (exp))
- return *scm_lookupcar (scm_cons (exp, SCM_UNDEFINED), env, 1);
- else
- return SCM_I_XEVAL (exp, env, scm_debug_mode_p);
-}
-
-SCM
-scm_primitive_eval_x (SCM exp)
-{
- SCM env;
- SCM transformer = scm_current_module_transformer ();
- if (SCM_NIMP (transformer))
- exp = scm_call_1 (transformer, exp);
- env = scm_top_level_env (scm_current_module_lookup_closure ());
- return scm_i_eval_x (exp, env);
-}
-
-SCM_DEFINE (scm_primitive_eval, "primitive-eval", 1, 0, 0,
- (SCM exp),
- "Evaluate @var{exp} in the top-level environment specified by\n"
- "the current module.")
-#define FUNC_NAME s_scm_primitive_eval
-{
- SCM env;
- SCM transformer = scm_current_module_transformer ();
- if (scm_is_true (transformer))
- exp = scm_call_1 (transformer, exp);
- env = scm_top_level_env (scm_current_module_lookup_closure ());
- return scm_i_eval (exp, env);
-}
-#undef FUNC_NAME
-
-
-/* Eval does not take the second arg optionally. This is intentional
- * in order to be R5RS compatible, and to prepare for the new module
- * system, where we would like to make the choice of evaluation
- * environment explicit. */
-
-SCM
-scm_eval_x (SCM exp, SCM module_or_state)
-{
- SCM res;
-
- scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
- if (scm_is_dynamic_state (module_or_state))
- scm_dynwind_current_dynamic_state (module_or_state);
- else
- scm_dynwind_current_module (module_or_state);
-
- res = scm_primitive_eval_x (exp);
-
- scm_dynwind_end ();
- return res;
-}
-
-SCM_DEFINE (scm_eval, "eval", 2, 0, 0,
- (SCM exp, SCM module_or_state),
- "Evaluate @var{exp}, a list representing a Scheme expression,\n"
- "in the top-level environment specified by\n"
- "@var{module_or_state}.\n"
- "While @var{exp} is evaluated (using @code{primitive-eval}),\n"
- "@var{module_or_state} is made the current module when\n"
- "it is a module, or the current dynamic state when it is\n"
- "a dynamic state."
- "Example: (eval '(+ 1 2) (interaction-environment))")
-#define FUNC_NAME s_scm_eval
-{
- SCM res;
-
- scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
- if (scm_is_dynamic_state (module_or_state))
- scm_dynwind_current_dynamic_state (module_or_state);
- else
- {
- SCM_VALIDATE_MODULE (2, module_or_state);
- scm_dynwind_current_module (module_or_state);
- }
-
- res = scm_primitive_eval (exp);
-
- scm_dynwind_end ();
- return res;
-}
-#undef FUNC_NAME
-
-
-/* At this point, deval and scm_dapply are generated.
- */
-
-#define DEVAL
-#include "eval.i.c"
-#undef DEVAL
-#include "eval.i.c"
-
-
-void
-scm_init_eval ()
-{
- scm_i_pthread_mutex_init (&source_mutex,
- scm_i_pthread_mutexattr_recursive);
-
- scm_init_opts (scm_evaluator_traps,
- scm_evaluator_trap_table);
- scm_init_opts (scm_eval_options_interface,
- scm_eval_opts);
-
- scm_tc16_promise = scm_make_smob_type ("promise", 0);
- scm_set_smob_mark (scm_tc16_promise, promise_mark);
- scm_set_smob_free (scm_tc16_promise, promise_free);
- scm_set_smob_print (scm_tc16_promise, promise_print);
-
- undefineds = scm_list_1 (SCM_UNDEFINED);
- SCM_SETCDR (undefineds, undefineds);
- scm_permanent_object (undefineds);
-
- scm_listofnull = scm_list_1 (SCM_EOL);
-
- f_apply = scm_c_define_subr ("apply", scm_tc7_lsubr_2, scm_apply);
- scm_permanent_object (f_apply);
-
-#include "libguile/eval.x"
-
- scm_add_feature ("delay");
-}
-
-/*
- Local Variables:
- c-file-style: "gnu"
- End:
-*/
-
+/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009
+ * 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
+ */
+
+\f
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <alloca.h>
+
+#include "libguile/__scm.h"
+
+#include <assert.h>
+#include "libguile/_scm.h"
+#include "libguile/alist.h"
+#include "libguile/async.h"
+#include "libguile/continuations.h"
+#include "libguile/debug.h"
+#include "libguile/deprecation.h"
+#include "libguile/dynwind.h"
+#include "libguile/eq.h"
+#include "libguile/feature.h"
+#include "libguile/fluids.h"
+#include "libguile/goops.h"
+#include "libguile/hash.h"
+#include "libguile/hashtab.h"
+#include "libguile/lang.h"
+#include "libguile/list.h"
+#include "libguile/macros.h"
+#include "libguile/memoize.h"
+#include "libguile/modules.h"
+#include "libguile/ports.h"
+#include "libguile/print.h"
+#include "libguile/procprop.h"
+#include "libguile/programs.h"
+#include "libguile/root.h"
+#include "libguile/smob.h"
+#include "libguile/srcprop.h"
+#include "libguile/stackchk.h"
+#include "libguile/strings.h"
+#include "libguile/threads.h"
+#include "libguile/throw.h"
+#include "libguile/validate.h"
+#include "libguile/values.h"
+#include "libguile/vectors.h"
+#include "libguile/vm.h"
+
+#include "libguile/eval.h"
+#include "libguile/private-options.h"
+
+\f
+
+
+/* We have three levels of EVAL here:
+
+ - eval (exp, env)
+
+ evaluates EXP in environment ENV. ENV is a lexical environment
+ structure as used by the actual tree code evaluator. When ENV is
+ a top-level environment, then changes to the current module are
+ tracked by updating ENV so that it continues to be in sync with
+ the current module.
+
+ - scm_primitive_eval (exp)
+
+ evaluates EXP in the top-level environment as determined by the
+ current module. This is done by constructing a suitable
+ environment and calling eval. Thus, changes to the
+ top-level module are tracked normally.
+
+ - scm_eval (exp, mod)
+
+ evaluates EXP while MOD is the current module. This is done
+ by setting the current module to MOD_OR_STATE, invoking
+ scm_primitive_eval on EXP, and then restoring the current module
+ to the value it had previously. That is, while EXP is evaluated,
+ changes to the current module (or dynamic state) are tracked,
+ but these changes do not persist when scm_eval returns.
+
+*/
+
+
+#if 0
+#define CAR(x) SCM_CAR(x)
+#define CDR(x) SCM_CDR(x)
+#define CAAR(x) SCM_CAAR(x)
+#define CADR(x) SCM_CADR(x)
+#define CDAR(x) SCM_CDAR(x)
+#define CDDR(x) SCM_CDDR(x)
+#define CADDR(x) SCM_CADDR(x)
+#define CDDDR(x) SCM_CDDDR(x)
+#else
+#define CAR(x) scm_car(x)
+#define CDR(x) scm_cdr(x)
+#define CAAR(x) scm_caar(x)
+#define CADR(x) scm_cadr(x)
+#define CDAR(x) scm_cdar(x)
+#define CDDR(x) scm_cddr(x)
+#define CADDR(x) scm_caddr(x)
+#define CDDDR(x) scm_cdddr(x)
+#endif
+
+
+SCM_SYMBOL (scm_unbound_variable_key, "unbound-variable");
+
+static void error_used_before_defined (void)
+{
+ scm_error (scm_unbound_variable_key, NULL,
+ "Variable used before given a value", SCM_EOL, SCM_BOOL_F);
+}
+
+int
+scm_badargsp (SCM formals, SCM args)
+{
+ while (!scm_is_null (formals))
+ {
+ if (!scm_is_pair (formals))
+ return 0;
+ if (scm_is_null (args))
+ return 1;
+ formals = CDR (formals);
+ args = CDR (args);
+ }
+ return !scm_is_null (args) ? 1 : 0;
+}
+
+/* the environment:
+ (VAL ... . MOD)
+ If MOD is #f, it means the environment was captured before modules were
+ booted.
+ If MOD is the literal value '(), we are evaluating at the top level, and so
+ should track changes to the current module. You have to be careful in this
+ case, because further lexical contours should capture the current module.
+*/
+#define CAPTURE_ENV(env) \
+ ((env == SCM_EOL) ? scm_current_module () : \
+ ((env == SCM_BOOL_F) ? scm_the_root_module () : env))
+
+static SCM
+eval (SCM x, SCM env)
+{
+ SCM mx;
+ SCM proc = SCM_UNDEFINED, args = SCM_EOL;
+
+ loop:
+ SCM_TICK;
+ if (!SCM_MEMOIZED_P (x))
+ abort ();
+
+ mx = SCM_MEMOIZED_ARGS (x);
+ switch (SCM_MEMOIZED_TAG (x))
+ {
+ case SCM_M_BEGIN:
+ for (; !scm_is_null (CDR (mx)); mx = CDR (mx))
+ eval (CAR (mx), env);
+ x = CAR (mx);
+ goto loop;
+
+ case SCM_M_IF:
+ if (scm_is_true (eval (CAR (mx), env)))
+ x = CADR (mx);
+ else
+ x = CDDR (mx);
+ goto loop;
+
+ case SCM_M_LET:
+ {
+ SCM inits = CAR (mx);
+ SCM new_env = CAPTURE_ENV (env);
+ for (; scm_is_pair (inits); inits = CDR (inits))
+ new_env = scm_cons (eval (CAR (inits), env), new_env);
+ env = new_env;
+ x = CDR (mx);
+ goto loop;
+ }
+
+ case SCM_M_LAMBDA:
+ return scm_closure (mx, CAPTURE_ENV (env));
+
+ case SCM_M_QUOTE:
+ return mx;
+
+ case SCM_M_DEFINE:
+ scm_define (CAR (mx), eval (CDR (mx), env));
+ return SCM_UNSPECIFIED;
+
+ case SCM_M_APPLY:
+ /* Evaluate the procedure to be applied. */
+ proc = eval (CAR (mx), env);
+ /* Evaluate the argument holding the list of arguments */
+ args = eval (CADR (mx), env);
+
+ apply_proc:
+ /* Go here to tail-apply a procedure. PROC is the procedure and
+ * ARGS is the list of arguments. */
+ if (SCM_CLOSUREP (proc))
+ {
+ int nreq = SCM_CLOSURE_NUM_REQUIRED_ARGS (proc);
+ SCM new_env = SCM_ENV (proc);
+ if (SCM_CLOSURE_HAS_REST_ARGS (proc))
+ {
+ if (SCM_UNLIKELY (scm_ilength (args) < nreq))
+ scm_wrong_num_args (proc);
+ for (; nreq; nreq--, args = CDR (args))
+ new_env = scm_cons (CAR (args), new_env);
+ new_env = scm_cons (args, new_env);
+ }
+ else
+ {
+ if (SCM_UNLIKELY (scm_ilength (args) != nreq))
+ scm_wrong_num_args (proc);
+ for (; scm_is_pair (args); args = CDR (args))
+ new_env = scm_cons (CAR (args), new_env);
+ }
+ x = SCM_CLOSURE_BODY (proc);
+ env = new_env;
+ goto loop;
+ }
+ else
+ return scm_vm_apply (scm_the_vm (), proc, args);
+
+ case SCM_M_CALL:
+ /* Evaluate the procedure to be applied. */
+ proc = eval (CAR (mx), env);
+
+ mx = CDR (mx);
+
+ if (SCM_CLOSUREP (proc))
+ {
+ int nreq = SCM_CLOSURE_NUM_REQUIRED_ARGS (proc);
+ SCM new_env = SCM_ENV (proc);
+ if (SCM_CLOSURE_HAS_REST_ARGS (proc))
+ {
+ if (SCM_UNLIKELY (scm_ilength (mx) < nreq))
+ scm_wrong_num_args (proc);
+ for (; nreq; nreq--, mx = CDR (mx))
+ new_env = scm_cons (eval (CAR (mx), env), new_env);
+ {
+ SCM rest = SCM_EOL;
+ for (; scm_is_pair (mx); mx = CDR (mx))
+ rest = scm_cons (eval (CAR (mx), env), rest);
+ new_env = scm_cons (scm_reverse (rest),
+ new_env);
+ }
+ }
+ else
+ {
+ for (; scm_is_pair (mx); mx = CDR (mx), nreq--)
+ new_env = scm_cons (eval (CAR (mx), env), new_env);
+ if (SCM_UNLIKELY (nreq != 0))
+ scm_wrong_num_args (proc);
+ }
+ x = SCM_CLOSURE_BODY (proc);
+ env = new_env;
+ goto loop;
+ }
+ else
+ {
+ SCM rest = SCM_EOL;
+ for (; scm_is_pair (mx); mx = CDR (mx))
+ rest = scm_cons (eval (CAR (mx), env), rest);
+ return scm_vm_apply (scm_the_vm (), proc, scm_reverse (rest));
+ }
+
+ case SCM_M_CONT:
+ {
+ int first;
+ SCM val = scm_make_continuation (&first);
+
+ if (!first)
+ return val;
+ else
+ {
+ proc = eval (mx, env);
+ args = scm_list_1 (val);
+ goto apply_proc;
+ }
+ }
+
+ case SCM_M_CALL_WITH_VALUES:
+ {
+ SCM producer;
+ SCM v;
+
+ producer = eval (CAR (mx), env);
+ proc = eval (CDR (mx), env); /* proc is the consumer. */
+ v = scm_vm_apply (scm_the_vm (), producer, SCM_EOL);
+ if (SCM_VALUESP (v))
+ args = scm_struct_ref (v, SCM_INUM0);
+ else
+ args = scm_list_1 (v);
+ goto apply_proc;
+ }
+
+ case SCM_M_LEXICAL_REF:
+ {
+ int n;
+ SCM ret;
+ for (n = SCM_I_INUM (mx); n; n--)
+ env = CDR (env);
+ ret = CAR (env);
+ if (SCM_UNLIKELY (SCM_UNBNDP (ret)))
+ /* we don't know what variable, though, because we don't have its
+ name */
+ error_used_before_defined ();
+ return ret;
+ }
+
+ case SCM_M_LEXICAL_SET:
+ {
+ int n;
+ SCM val = eval (CDR (mx), env);
+ for (n = SCM_I_INUM (CAR (mx)); n; n--)
+ env = CDR (env);
+ SCM_SETCAR (env, val);
+ return SCM_UNSPECIFIED;
+ }
+
+ case SCM_M_TOPLEVEL_REF:
+ if (SCM_VARIABLEP (mx))
+ return SCM_VARIABLE_REF (mx);
+ else
+ {
+ while (scm_is_pair (env))
+ env = scm_cdr (env);
+ return SCM_VARIABLE_REF
+ (scm_memoize_variable_access_x (x, CAPTURE_ENV (env)));
+ }
+
+ case SCM_M_TOPLEVEL_SET:
+ {
+ SCM var = CAR (mx);
+ SCM val = eval (CDR (mx), env);
+ if (SCM_VARIABLEP (var))
+ {
+ SCM_VARIABLE_SET (var, val);
+ return SCM_UNSPECIFIED;
+ }
+ else
+ {
+ while (scm_is_pair (env))
+ env = scm_cdr (env);
+ SCM_VARIABLE_SET
+ (scm_memoize_variable_access_x (x, CAPTURE_ENV (env)),
+ val);
+ return SCM_UNSPECIFIED;
+ }
+ }
+
+ case SCM_M_MODULE_REF:
+ if (SCM_VARIABLEP (mx))
+ return SCM_VARIABLE_REF (mx);
+ else
+ return SCM_VARIABLE_REF
+ (scm_memoize_variable_access_x (x, SCM_BOOL_F));
+
+ case SCM_M_MODULE_SET:
+ if (SCM_VARIABLEP (CDR (mx)))
+ {
+ SCM_VARIABLE_SET (CDR (mx), eval (CAR (mx), env));
+ return SCM_UNSPECIFIED;
+ }
+ else
+ {
+ SCM_VARIABLE_SET
+ (scm_memoize_variable_access_x (x, SCM_BOOL_F),
+ eval (CAR (mx), env));
+ return SCM_UNSPECIFIED;
+ }
+
+ default:
+ abort ();
+ }
+}
+
+SCM
+scm_closure_apply (SCM proc, SCM args)
+{
+ unsigned int nargs;
+ int nreq;
+ SCM env;
+
+ /* Args contains a list of all args. */
+ {
+ int ilen = scm_ilength (args);
+ if (ilen < 0)
+ scm_wrong_num_args (proc);
+ nargs = ilen;
+ }
+
+ nreq = SCM_CLOSURE_NUM_REQUIRED_ARGS (proc);
+ env = SCM_ENV (proc);
+ if (SCM_CLOSURE_HAS_REST_ARGS (proc))
+ {
+ if (SCM_UNLIKELY (scm_ilength (args) < nreq))
+ scm_wrong_num_args (proc);
+ for (; nreq; nreq--, args = CDR (args))
+ env = scm_cons (CAR (args), env);
+ env = scm_cons (args, env);
+ }
+ else
+ {
+ for (; scm_is_pair (args); args = CDR (args), nreq--)
+ env = scm_cons (CAR (args), env);
+ if (SCM_UNLIKELY (nreq != 0))
+ scm_wrong_num_args (proc);
+ }
+ return eval (SCM_CLOSURE_BODY (proc), env);
+}
+
+
+scm_t_option scm_eval_opts[] = {
+ { SCM_OPTION_INTEGER, "stack", 22000, "Size of thread stacks (in machine words)." },
+ { 0 }
+};
+
+scm_t_option scm_debug_opts[] = {
+ { SCM_OPTION_BOOLEAN, "cheap", 1,
+ "*This option is now obsolete. Setting it has no effect." },
+ { SCM_OPTION_BOOLEAN, "breakpoints", 0, "*Check for breakpoints." },
+ { SCM_OPTION_BOOLEAN, "trace", 0, "*Trace mode." },
+ { SCM_OPTION_BOOLEAN, "procnames", 1,
+ "Record procedure names at definition." },
+ { SCM_OPTION_BOOLEAN, "backwards", 0,
+ "Display backtrace in anti-chronological order." },
+ { SCM_OPTION_INTEGER, "width", 79, "Maximal width of backtrace." },
+ { SCM_OPTION_INTEGER, "indent", 10, "Maximal indentation in backtrace." },
+ { SCM_OPTION_INTEGER, "frames", 3,
+ "Maximum number of tail-recursive frames in backtrace." },
+ { SCM_OPTION_INTEGER, "maxdepth", 1000,
+ "Maximal number of stored backtrace frames." },
+ { SCM_OPTION_INTEGER, "depth", 20, "Maximal length of printed backtrace." },
+ { SCM_OPTION_BOOLEAN, "backtrace", 0, "Show backtrace on error." },
+ { SCM_OPTION_BOOLEAN, "debug", 0, "Use the debugging evaluator." },
+ /* This default stack limit will be overridden by debug.c:init_stack_limit(),
+ if we have getrlimit() and the stack limit is not INFINITY. But it is still
+ important, as some systems have both the soft and the hard limits set to
+ INFINITY; in that case we fall back to this value.
+
+ The situation is aggravated by certain compilers, which can consume
+ "beaucoup de stack", as they say in France.
+
+ See http://thread.gmane.org/gmane.lisp.guile.devel/8599/focus=8662 for
+ more discussion. This setting is 640 KB on 32-bit arches (should be enough
+ for anyone!) or a whoppin' 1280 KB on 64-bit arches.
+ */
+ { SCM_OPTION_INTEGER, "stack", 160000, "Stack size limit (measured in words; 0 = no check)." },
+ { SCM_OPTION_SCM, "show-file-name", (unsigned long)SCM_BOOL_T,
+ "Show file names and line numbers "
+ "in backtraces when not `#f'. A value of `base' "
+ "displays only base names, while `#t' displays full names."},
+ { SCM_OPTION_BOOLEAN, "warn-deprecated", 0,
+ "Warn when deprecated features are used." },
+ { 0 },
+};
+
+
+/*
+ * this ordering is awkward and illogical, but we maintain it for
+ * compatibility. --hwn
+ */
+scm_t_option scm_evaluator_trap_table[] = {
+ { SCM_OPTION_BOOLEAN, "traps", 0, "Enable evaluator traps." },
+ { SCM_OPTION_BOOLEAN, "enter-frame", 0, "Trap when eval enters new frame." },
+ { SCM_OPTION_BOOLEAN, "apply-frame", 0, "Trap when entering apply." },
+ { SCM_OPTION_BOOLEAN, "exit-frame", 0, "Trap when exiting eval or apply." },
+ { SCM_OPTION_SCM, "enter-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for enter-frame traps." },
+ { SCM_OPTION_SCM, "apply-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for apply-frame traps." },
+ { SCM_OPTION_SCM, "exit-frame-handler", (unsigned long)SCM_BOOL_F, "Handler for exit-frame traps." },
+ { SCM_OPTION_BOOLEAN, "memoize-symbol", 0, "Trap when memoizing a symbol." },
+ { SCM_OPTION_SCM, "memoize-symbol-handler", (unsigned long)SCM_BOOL_F, "The handler for memoization." },
+ { 0 }
+};
+
+
+SCM_DEFINE (scm_eval_options_interface, "eval-options-interface", 0, 1, 0,
+ (SCM setting),
+ "Option interface for the evaluation options. Instead of using\n"
+ "this procedure directly, use the procedures @code{eval-enable},\n"
+ "@code{eval-disable}, @code{eval-set!} and @code{eval-options}.")
+#define FUNC_NAME s_scm_eval_options_interface
+{
+ SCM ans;
+
+ scm_dynwind_begin (0);
+ scm_dynwind_critical_section (SCM_BOOL_F);
+ ans = scm_options (setting,
+ scm_eval_opts,
+ FUNC_NAME);
+ scm_dynwind_end ();
+
+ return ans;
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_evaluator_traps, "evaluator-traps-interface", 0, 1, 0,
+ (SCM setting),
+ "Option interface for the evaluator trap options.")
+#define FUNC_NAME s_scm_evaluator_traps
+{
+ SCM ans;
+
+
+ scm_options_try (setting,
+ scm_evaluator_trap_table,
+ FUNC_NAME, 1);
+ SCM_CRITICAL_SECTION_START;
+ ans = scm_options (setting,
+ scm_evaluator_trap_table,
+ FUNC_NAME);
+
+ /* njrev: same again. */
+ SCM_CRITICAL_SECTION_END;
+ return ans;
+}
+#undef FUNC_NAME
+
+
+
+\f
+
+/* Simple procedure calls
+ */
+
+SCM
+scm_call_0 (SCM proc)
+{
+ if (SCM_PROGRAM_P (proc))
+ return scm_c_vm_run (scm_the_vm (), proc, NULL, 0);
+ else
+ return scm_apply (proc, SCM_EOL, SCM_EOL);
+}
+
+SCM
+scm_call_1 (SCM proc, SCM arg1)
+{
+ if (SCM_PROGRAM_P (proc))
+ return scm_c_vm_run (scm_the_vm (), proc, &arg1, 1);
+ else
+ return scm_apply (proc, arg1, scm_listofnull);
+}
+
+SCM
+scm_call_2 (SCM proc, SCM arg1, SCM arg2)
+{
+ if (SCM_PROGRAM_P (proc))
+ {
+ SCM args[] = { arg1, arg2 };
+ return scm_c_vm_run (scm_the_vm (), proc, args, 2);
+ }
+ else
+ return scm_apply (proc, arg1, scm_cons (arg2, scm_listofnull));
+}
+
+SCM
+scm_call_3 (SCM proc, SCM arg1, SCM arg2, SCM arg3)
+{
+ if (SCM_PROGRAM_P (proc))
+ {
+ SCM args[] = { arg1, arg2, arg3 };
+ return scm_c_vm_run (scm_the_vm (), proc, args, 3);
+ }
+ else
+ return scm_apply (proc, arg1, scm_cons2 (arg2, arg3, scm_listofnull));
+}
+
+SCM
+scm_call_4 (SCM proc, SCM arg1, SCM arg2, SCM arg3, SCM arg4)
+{
+ if (SCM_PROGRAM_P (proc))
+ {
+ SCM args[] = { arg1, arg2, arg3, arg4 };
+ return scm_c_vm_run (scm_the_vm (), proc, args, 4);
+ }
+ else
+ return scm_apply (proc, arg1, scm_cons2 (arg2, arg3,
+ scm_cons (arg4, scm_listofnull)));
+}
+
+/* Simple procedure applies
+ */
+
+SCM
+scm_apply_0 (SCM proc, SCM args)
+{
+ return scm_apply (proc, args, SCM_EOL);
+}
+
+SCM
+scm_apply_1 (SCM proc, SCM arg1, SCM args)
+{
+ return scm_apply (proc, scm_cons (arg1, args), SCM_EOL);
+}
+
+SCM
+scm_apply_2 (SCM proc, SCM arg1, SCM arg2, SCM args)
+{
+ return scm_apply (proc, scm_cons2 (arg1, arg2, args), SCM_EOL);
+}
+
+SCM
+scm_apply_3 (SCM proc, SCM arg1, SCM arg2, SCM arg3, SCM args)
+{
+ return scm_apply (proc, scm_cons (arg1, scm_cons2 (arg2, arg3, args)),
+ SCM_EOL);
+}
+
+/* This code processes the arguments to apply:
+
+ (apply PROC ARG1 ... ARGS)
+
+ Given a list (ARG1 ... ARGS), this function conses the ARG1
+ ... arguments onto the front of ARGS, and returns the resulting
+ list. Note that ARGS is a list; thus, the argument to this
+ function is a list whose last element is a list.
+
+ Apply calls this function, and applies PROC to the elements of the
+ result. apply:nconc2last takes care of building the list of
+ arguments, given (ARG1 ... ARGS).
+
+ Rather than do new consing, apply:nconc2last destroys its argument.
+ On that topic, this code came into my care with the following
+ beautifully cryptic comment on that topic: "This will only screw
+ you if you do (scm_apply scm_apply '( ... ))" If you know what
+ they're referring to, send me a patch to this comment. */
+
+SCM_DEFINE (scm_nconc2last, "apply:nconc2last", 1, 0, 0,
+ (SCM lst),
+ "Given a list (@var{arg1} @dots{} @var{args}), this function\n"
+ "conses the @var{arg1} @dots{} arguments onto the front of\n"
+ "@var{args}, and returns the resulting list. Note that\n"
+ "@var{args} is a list; thus, the argument to this function is\n"
+ "a list whose last element is a list.\n"
+ "Note: Rather than do new consing, @code{apply:nconc2last}\n"
+ "destroys its argument, so use with care.")
+#define FUNC_NAME s_scm_nconc2last
+{
+ SCM *lloc;
+ SCM_VALIDATE_NONEMPTYLIST (1, lst);
+ lloc = &lst;
+ while (!scm_is_null (SCM_CDR (*lloc))) /* Perhaps should be
+ SCM_NULL_OR_NIL_P, but not
+ needed in 99.99% of cases,
+ and it could seriously hurt
+ performance. - Neil */
+ lloc = SCM_CDRLOC (*lloc);
+ SCM_ASSERT (scm_ilength (SCM_CAR (*lloc)) >= 0, lst, SCM_ARG1, FUNC_NAME);
+ *lloc = SCM_CAR (*lloc);
+ return lst;
+}
+#undef FUNC_NAME
+
+
+
+/* Typechecking for multi-argument MAP and FOR-EACH.
+
+ Verify that each element of the vector ARGV, except for the first,
+ is a proper list whose length is LEN. Attribute errors to WHO,
+ and claim that the i'th element of ARGV is WHO's i+2'th argument. */
+static inline void
+check_map_args (SCM argv,
+ long len,
+ SCM gf,
+ SCM proc,
+ SCM args,
+ const char *who)
+{
+ long i;
+
+ for (i = SCM_SIMPLE_VECTOR_LENGTH (argv) - 1; i >= 1; i--)
+ {
+ SCM elt = SCM_SIMPLE_VECTOR_REF (argv, i);
+ long elt_len = scm_ilength (elt);
+
+ if (elt_len < 0)
+ {
+ if (gf)
+ scm_apply_generic (gf, scm_cons (proc, args));
+ else
+ scm_wrong_type_arg (who, i + 2, elt);
+ }
+
+ if (elt_len != len)
+ scm_out_of_range_pos (who, elt, scm_from_long (i + 2));
+ }
+}
+
+
+SCM_GPROC (s_map, "map", 2, 0, 1, scm_map, g_map);
+
+/* Note: Currently, scm_map applies PROC to the argument list(s)
+ sequentially, starting with the first element(s). This is used in
+ evalext.c where the Scheme procedure `map-in-order', which guarantees
+ sequential behaviour, is implemented using scm_map. If the
+ behaviour changes, we need to update `map-in-order'.
+*/
+
+SCM
+scm_map (SCM proc, SCM arg1, SCM args)
+#define FUNC_NAME s_map
+{
+ long i, len;
+ SCM res = SCM_EOL;
+ SCM *pres = &res;
+
+ len = scm_ilength (arg1);
+ SCM_GASSERTn (len >= 0,
+ g_map, scm_cons2 (proc, arg1, args), SCM_ARG2, s_map);
+ SCM_VALIDATE_REST_ARGUMENT (args);
+ if (scm_is_null (args))
+ {
+ SCM_GASSERT2 (scm_is_true (scm_procedure_p (proc)), g_map, proc, arg1, SCM_ARG1, s_map);
+ while (SCM_NIMP (arg1))
+ {
+ *pres = scm_list_1 (scm_call_1 (proc, SCM_CAR (arg1)));
+ pres = SCM_CDRLOC (*pres);
+ arg1 = SCM_CDR (arg1);
+ }
+ return res;
+ }
+ if (scm_is_null (SCM_CDR (args)))
+ {
+ SCM arg2 = SCM_CAR (args);
+ int len2 = scm_ilength (arg2);
+ SCM_GASSERTn (scm_is_true (scm_procedure_p (proc)), g_map,
+ scm_cons2 (proc, arg1, args), SCM_ARG1, s_map);
+ SCM_GASSERTn (len2 >= 0,
+ g_map, scm_cons2 (proc, arg1, args), SCM_ARG3, s_map);
+ if (len2 != len)
+ SCM_OUT_OF_RANGE (3, arg2);
+ while (SCM_NIMP (arg1))
+ {
+ *pres = scm_list_1 (scm_call_2 (proc, SCM_CAR (arg1), SCM_CAR (arg2)));
+ pres = SCM_CDRLOC (*pres);
+ arg1 = SCM_CDR (arg1);
+ arg2 = SCM_CDR (arg2);
+ }
+ return res;
+ }
+ arg1 = scm_cons (arg1, args);
+ args = scm_vector (arg1);
+ check_map_args (args, len, g_map, proc, arg1, s_map);
+ while (1)
+ {
+ arg1 = SCM_EOL;
+ for (i = SCM_SIMPLE_VECTOR_LENGTH (args) - 1; i >= 0; i--)
+ {
+ SCM elt = SCM_SIMPLE_VECTOR_REF (args, i);
+ if (SCM_IMP (elt))
+ return res;
+ arg1 = scm_cons (SCM_CAR (elt), arg1);
+ SCM_SIMPLE_VECTOR_SET (args, i, SCM_CDR (elt));
+ }
+ *pres = scm_list_1 (scm_apply (proc, arg1, SCM_EOL));
+ pres = SCM_CDRLOC (*pres);
+ }
+}
+#undef FUNC_NAME
+
+
+SCM_GPROC (s_for_each, "for-each", 2, 0, 1, scm_for_each, g_for_each);
+
+SCM
+scm_for_each (SCM proc, SCM arg1, SCM args)
+#define FUNC_NAME s_for_each
+{
+ long i, len;
+ len = scm_ilength (arg1);
+ SCM_GASSERTn (len >= 0, g_for_each, scm_cons2 (proc, arg1, args),
+ SCM_ARG2, s_for_each);
+ SCM_VALIDATE_REST_ARGUMENT (args);
+ if (scm_is_null (args))
+ {
+ SCM_GASSERT2 (scm_is_true (scm_procedure_p (proc)), g_for_each,
+ proc, arg1, SCM_ARG1, s_for_each);
+ while (SCM_NIMP (arg1))
+ {
+ scm_call_1 (proc, SCM_CAR (arg1));
+ arg1 = SCM_CDR (arg1);
+ }
+ return SCM_UNSPECIFIED;
+ }
+ if (scm_is_null (SCM_CDR (args)))
+ {
+ SCM arg2 = SCM_CAR (args);
+ int len2 = scm_ilength (arg2);
+ SCM_GASSERTn (scm_is_true (scm_procedure_p (proc)), g_for_each,
+ scm_cons2 (proc, arg1, args), SCM_ARG1, s_for_each);
+ SCM_GASSERTn (len2 >= 0, g_for_each,
+ scm_cons2 (proc, arg1, args), SCM_ARG3, s_for_each);
+ if (len2 != len)
+ SCM_OUT_OF_RANGE (3, arg2);
+ while (SCM_NIMP (arg1))
+ {
+ scm_call_2 (proc, SCM_CAR (arg1), SCM_CAR (arg2));
+ arg1 = SCM_CDR (arg1);
+ arg2 = SCM_CDR (arg2);
+ }
+ return SCM_UNSPECIFIED;
+ }
+ arg1 = scm_cons (arg1, args);
+ args = scm_vector (arg1);
+ check_map_args (args, len, g_for_each, proc, arg1, s_for_each);
+ while (1)
+ {
+ arg1 = SCM_EOL;
+ for (i = SCM_SIMPLE_VECTOR_LENGTH (args) - 1; i >= 0; i--)
+ {
+ SCM elt = SCM_SIMPLE_VECTOR_REF (args, i);
+ if (SCM_IMP (elt))
+ return SCM_UNSPECIFIED;
+ arg1 = scm_cons (SCM_CAR (elt), arg1);
+ SCM_SIMPLE_VECTOR_SET (args, i, SCM_CDR (elt));
+ }
+ scm_apply (proc, arg1, SCM_EOL);
+ }
+}
+#undef FUNC_NAME
+
+
+SCM
+scm_closure (SCM code, SCM env)
+{
+ SCM z;
+ SCM closcar = scm_cons (code, SCM_EOL);
+ z = scm_immutable_cell (SCM_UNPACK (closcar) + scm_tc3_closure,
+ (scm_t_bits) env);
+ scm_remember_upto_here (closcar);
+ return z;
+}
+
+
+static SCM
+scm_c_primitive_eval (SCM exp)
+{
+ SCM transformer = scm_current_module_transformer ();
+ if (scm_is_true (transformer))
+ exp = scm_call_1 (transformer, exp);
+ exp = scm_memoize_expression (exp);
+ return eval (exp, SCM_EOL);
+}
+
+static SCM var_primitive_eval;
+SCM
+scm_primitive_eval (SCM exp)
+{
+ return scm_c_vm_run (scm_the_vm (), scm_variable_ref (var_primitive_eval),
+ &exp, 1);
+}
+
+
+/* Eval does not take the second arg optionally. This is intentional
+ * in order to be R5RS compatible, and to prepare for the new module
+ * system, where we would like to make the choice of evaluation
+ * environment explicit. */
+
+SCM_DEFINE (scm_eval, "eval", 2, 0, 0,
+ (SCM exp, SCM module_or_state),
+ "Evaluate @var{exp}, a list representing a Scheme expression,\n"
+ "in the top-level environment specified by\n"
+ "@var{module_or_state}.\n"
+ "While @var{exp} is evaluated (using @code{primitive-eval}),\n"
+ "@var{module_or_state} is made the current module when\n"
+ "it is a module, or the current dynamic state when it is\n"
+ "a dynamic state."
+ "Example: (eval '(+ 1 2) (interaction-environment))")
+#define FUNC_NAME s_scm_eval
+{
+ SCM res;
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ if (scm_is_dynamic_state (module_or_state))
+ scm_dynwind_current_dynamic_state (module_or_state);
+ else if (scm_module_system_booted_p)
+ {
+ SCM_VALIDATE_MODULE (2, module_or_state);
+ scm_dynwind_current_module (module_or_state);
+ }
+ /* otherwise if the module system isn't booted, ignore the module arg */
+
+ res = scm_primitive_eval (exp);
+
+ scm_dynwind_end ();
+ return res;
+}
+#undef FUNC_NAME
+
+
+static SCM f_apply;
+
+/* Apply a function to a list of arguments.
+
+ This function is exported to the Scheme level as taking two
+ required arguments and a tail argument, as if it were:
+ (lambda (proc arg1 . args) ...)
+ Thus, if you just have a list of arguments to pass to a procedure,
+ pass the list as ARG1, and '() for ARGS. If you have some fixed
+ args, pass the first as ARG1, then cons any remaining fixed args
+ onto the front of your argument list, and pass that as ARGS. */
+
+SCM
+scm_apply (SCM proc, SCM arg1, SCM args)
+{
+ /* Fix things up so that args contains all args. */
+ if (scm_is_null (args))
+ args = arg1;
+ else
+ args = scm_cons_star (arg1, args);
+
+ return scm_vm_apply (scm_the_vm (), proc, args);
+}
+
+
+void
+scm_init_eval ()
+{
+ SCM primitive_eval;
+
+ scm_init_opts (scm_evaluator_traps,
+ scm_evaluator_trap_table);
+ scm_init_opts (scm_eval_options_interface,
+ scm_eval_opts);
+
+ scm_listofnull = scm_list_1 (SCM_EOL);
+
+ f_apply = scm_c_define_subr ("apply", scm_tc7_lsubr_2, scm_apply);
+ scm_permanent_object (f_apply);
+
+ primitive_eval = scm_c_make_gsubr ("primitive-eval", 1, 0, 0,
+ scm_c_primitive_eval);
+ var_primitive_eval = scm_define (SCM_SUBR_NAME (primitive_eval),
+ primitive_eval);
+
+#include "libguile/eval.x"
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
+
HCoop / bpt / guile.git / blobdiff