--- /dev/null
+/* 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
+
+/* This file is read twice in order to produce debugging versions of ceval and
+ * scm_apply. These functions, deval and scm_dapply, are produced when we
+ * define the preprocessor macro DEVAL. The file is divided into sections
+ * which are treated differently with respect to DEVAL. The heads of these
+ * sections are marked with the string "SECTION:". */
+
+/* SECTION: This code is compiled once.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/__scm.h"
+
+#ifndef DEVAL
+
+/* This blob per the Autoconf manual (under "Particular Functions"), updated
+ to match that of Gnulib. */
+#ifndef alloca
+# if HAVE_ALLOCA_H
+# include <alloca.h>
+# elif defined __GNUC__
+# define alloca __builtin_alloca
+# elif defined _AIX
+# define alloca __alloca
+# elif defined _MSC_VER
+# include <malloc.h>
+# define alloca _alloca
+# else
+# include <stddef.h>
+# ifdef __cplusplus
+extern "C"
+# endif
+void *alloca (size_t);
+# endif
+#endif
+
+#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"
+
+\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 eval_letrec_inits (SCM env, SCM init_forms, SCM **init_values_eol);
+
+\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_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. This is an attempt at
+ * explanation.
+ *
+ * The following macros should be used in code which is read twice (where the
+ * choice of evaluator is hard soldered):
+ *
+ * CEVAL is the symbol used within one evaluator to call itself.
+ * Originally, it is defined to ceval, but is redefined to deval during the
+ * second pass.
+ *
+ * SCM_I_EVALIM is used when it is known that the expression is an
+ * immediate. (This macro never calls an evaluator.)
+ *
+ * EVAL 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.
+ *
+ * EVALCAR 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.
+ *
+ * The following macros should be used in code which is read once
+ * (where the choice of evaluator is dynamic):
+ *
+ * SCM_I_XEVAL corresponds to EVAL, but uses ceval *or* deval depending on the
+ * debugging mode.
+ *
+ * SCM_I_XEVALCAR corresponds to EVALCAR, but uses ceval *or* deval depending
+ * on the debugging mode.
+ *
+ * The main motivation for keeping this plethora is efficiency
+ * together with maintainability (=> locality of code).
+ */
+
+static SCM ceval (SCM x, SCM env);
+static SCM deval (SCM x, SCM env);
+#define CEVAL ceval
+
+
+#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) \
+ (SCM_IMP (x) \
+ ? SCM_I_EVALIM2 (x) \
+ : (SCM_VARIABLEP (x) \
+ ? SCM_VARIABLE_REF (x) \
+ : (scm_is_pair (x) \
+ ? (scm_debug_mode_p \
+ ? deval ((x), (env)) \
+ : ceval ((x), (env))) \
+ : (x))))
+
+#define SCM_I_XEVALCAR(x, env) \
+ (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)) \
+ ? (scm_debug_mode_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)))))
+
+#define EVAL(x, env) \
+ (SCM_IMP (x) \
+ ? SCM_I_EVALIM ((x), (env)) \
+ : (SCM_VARIABLEP (x) \
+ ? SCM_VARIABLE_REF (x) \
+ : (scm_is_pair (x) \
+ ? CEVAL ((x), (env)) \
+ : (x))))
+
+#define EVALCAR(x, env) \
+ (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)) \
+ ? 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
+scm_eval_args (SCM l, SCM env, SCM proc)
+{
+ SCM results = SCM_EOL, *lloc = &results, res;
+ while (scm_is_pair (l))
+ {
+ res = EVALCAR (l, env);
+
+ *lloc = scm_list_1 (res);
+ lloc = SCM_CDRLOC (*lloc);
+ l = SCM_CDR (l);
+ }
+ if (!scm_is_null (l))
+ scm_wrong_num_args (proc);
+ return results;
+}
+
+
+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);
+ code = next;
+ next = SCM_CDR (code);
+ }
+ return SCM_I_XEVALCAR (code, env);
+}
+
+#endif /* !DEVAL */
+
+
+/* SECTION: This code is specific for the debugging support. One
+ * branch is read when DEVAL isn't defined, the other when DEVAL is
+ * defined.
+ */
+
+#ifndef DEVAL
+
+#define SCM_APPLY scm_apply
+#define PREP_APPLY(proc, args)
+#define ENTER_APPLY
+#define RETURN(x) do { return x; } while (0)
+#ifdef STACK_CHECKING
+#ifndef NO_CEVAL_STACK_CHECKING
+#define EVAL_STACK_CHECKING
+#endif
+#endif
+
+#else /* !DEVAL */
+
+#undef CEVAL
+#define CEVAL deval /* Substitute all uses of ceval */
+
+#undef SCM_APPLY
+#define SCM_APPLY scm_dapply
+
+#undef PREP_APPLY
+#define PREP_APPLY(p, l) \
+{ ++debug.info; debug.info->a.proc = p; debug.info->a.args = l; }
+
+#undef ENTER_APPLY
+#define ENTER_APPLY \
+do { \
+ SCM_SET_ARGSREADY (debug);\
+ if (scm_check_apply_p && SCM_TRAPS_P)\
+ if (SCM_APPLY_FRAME_P || (SCM_TRACE_P && SCM_PROCTRACEP (proc)))\
+ {\
+ SCM tmp, tail = scm_from_bool(SCM_TRACED_FRAME_P (debug)); \
+ SCM_SET_TRACED_FRAME (debug); \
+ SCM_TRAPS_P = 0;\
+ tmp = scm_make_debugobj (&debug);\
+ scm_call_3 (SCM_APPLY_FRAME_HDLR, scm_sym_apply_frame, tmp, tail);\
+ SCM_TRAPS_P = 1;\
+ }\
+} while (0)
+
+#undef RETURN
+#define RETURN(e) do { proc = (e); goto exit; } while (0)
+
+#ifdef STACK_CHECKING
+#ifndef EVAL_STACK_CHECKING
+#define EVAL_STACK_CHECKING
+#endif
+#endif
+
+
+/* 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;
+
+long scm_eval_stack;
+
+scm_t_option scm_eval_opts[] = {
+ { SCM_OPTION_INTEGER, "stack", 22000, "Size of thread stacks (in machine words)." }
+};
+
+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." }
+};
+
+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_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,
+ SCM_N_EVAL_OPTIONS,
+ 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_CRITICAL_SECTION_START;
+ ans = scm_options (setting,
+ scm_evaluator_trap_table,
+ SCM_N_EVALUATOR_TRAPS,
+ FUNC_NAME);
+ /* njrev: same again. */
+ SCM_RESET_DEBUG_MODE;
+ SCM_CRITICAL_SECTION_END;
+ return ans;
+}
+#undef FUNC_NAME
+
+
+static SCM
+deval_args (SCM l, SCM env, SCM proc, SCM *lloc)
+{
+ SCM *results = lloc;
+ while (scm_is_pair (l))
+ {
+ const SCM res = EVALCAR (l, env);
+
+ *lloc = scm_list_1 (res);
+ lloc = SCM_CDRLOC (*lloc);
+ l = SCM_CDR (l);
+ }
+ if (!scm_is_null (l))
+ scm_wrong_num_args (proc);
+ return *results;
+}
+
+static void
+eval_letrec_inits (SCM env, SCM init_forms, SCM **init_values_eol)
+{
+ SCM argv[10];
+ int i = 0, imax = sizeof (argv) / sizeof (SCM);
+
+ while (!scm_is_null (init_forms))
+ {
+ if (imax == i)
+ {
+ eval_letrec_inits (env, init_forms, init_values_eol);
+ break;
+ }
+ argv[i++] = EVALCAR (init_forms, env);
+ init_forms = SCM_CDR (init_forms);
+ }
+
+ for (i--; i >= 0; i--)
+ {
+ **init_values_eol = scm_list_1 (argv[i]);
+ *init_values_eol = SCM_CDRLOC (**init_values_eol);
+ }
+}
+
+#endif /* !DEVAL */
+
+
+/* SECTION: This code is compiled twice.
+ */
+
+
+/* Update the toplevel environment frame ENV so that it refers to the
+ * current module. */
+#define UPDATE_TOPLEVEL_ENV(env) \
+ do { \
+ SCM p = scm_current_module_lookup_closure (); \
+ if (p != SCM_CAR (env)) \
+ env = scm_top_level_env (p); \
+ } while (0)
+
+
+#define SCM_VALIDATE_NON_EMPTY_COMBINATION(x) \
+ ASSERT_SYNTAX (!scm_is_eq ((x), SCM_EOL), s_empty_combination, x)
+
+
+/* This is the evaluator. Like any real monster, it has three heads:
+ *
+ * ceval is the non-debugging evaluator, deval is the debugging version. Both
+ * are implemented using a common code base, using the following mechanism:
+ * CEVAL is a macro, which is either defined to ceval or deval. Thus, there
+ * is no function CEVAL, but the code for CEVAL actually compiles to either
+ * ceval or deval. When CEVAL is defined to ceval, it is known that the macro
+ * DEVAL is not defined. When CEVAL is defined to deval, then the macro DEVAL
+ * is known to be defined. Thus, in CEVAL parts for the debugging evaluator
+ * are enclosed within #ifdef DEVAL ... #endif.
+ *
+ * All three (ceval, deval and their common implementation CEVAL) take two
+ * input parameters, x and env: x is a single expression to be evalutated.
+ * env is the environment in which bindings are searched.
+ *
+ * x is known to be a pair. Since x is a single expression, it is necessarily
+ * in a tail position. If x is just a call to another function like in the
+ * expression (foo exp1 exp2 ...), the realization of that call therefore
+ * _must_not_ increase stack usage (the evaluation of exp1, exp2 etc.,
+ * however, may do so). This is realized by making extensive use of 'goto'
+ * statements within the evaluator: The gotos replace recursive calls to
+ * CEVAL, thus re-using the same stack frame that CEVAL was already using.
+ * If, however, x represents some form that requires to evaluate a sequence of
+ * expressions like (begin exp1 exp2 ...), then recursive calls to CEVAL are
+ * performed for all but the last expression of that sequence. */
+
+static SCM
+CEVAL (SCM x, SCM env)
+{
+ SCM proc, arg1;
+#ifdef DEVAL
+ scm_t_debug_frame debug;
+ scm_t_debug_info *debug_info_end;
+ debug.prev = scm_i_last_debug_frame ();
+ debug.status = 0;
+ /*
+ * The debug.vect contains twice as much scm_t_debug_info frames as the
+ * user has specified with (debug-set! frames <n>).
+ *
+ * Even frames are eval frames, odd frames are apply frames.
+ */
+ debug.vect = (scm_t_debug_info *) alloca (scm_debug_eframe_size
+ * sizeof (scm_t_debug_info));
+ debug.info = debug.vect;
+ debug_info_end = debug.vect + scm_debug_eframe_size;
+ scm_i_set_last_debug_frame (&debug);
+#endif
+#ifdef EVAL_STACK_CHECKING
+ if (scm_stack_checking_enabled_p && SCM_STACK_OVERFLOW_P (&proc))
+ {
+#ifdef DEVAL
+ debug.info->e.exp = x;
+ debug.info->e.env = env;
+#endif
+ scm_report_stack_overflow ();
+ }
+#endif
+
+#ifdef DEVAL
+ goto start;
+#endif
+
+loop:
+#ifdef DEVAL
+ SCM_CLEAR_ARGSREADY (debug);
+ if (SCM_OVERFLOWP (debug))
+ --debug.info;
+ /*
+ * In theory, this should be the only place where it is necessary to
+ * check for space in debug.vect since both eval frames and
+ * available space are even.
+ *
+ * For this to be the case, however, it is necessary that primitive
+ * special forms which jump back to `loop', `begin' or some similar
+ * label call PREP_APPLY.
+ */
+ else if (++debug.info >= debug_info_end)
+ {
+ SCM_SET_OVERFLOW (debug);
+ debug.info -= 2;
+ }
+
+start:
+ debug.info->e.exp = x;
+ debug.info->e.env = env;
+ if (scm_check_entry_p && SCM_TRAPS_P)
+ {
+ if (SCM_ENTER_FRAME_P
+ || (SCM_BREAKPOINTS_P && scm_c_source_property_breakpoint_p (x)))
+ {
+ SCM stackrep;
+ SCM tail = scm_from_bool (SCM_TAILRECP (debug));
+ SCM_SET_TAILREC (debug);
+ stackrep = scm_make_debugobj (&debug);
+ SCM_TRAPS_P = 0;
+ stackrep = scm_call_4 (SCM_ENTER_FRAME_HDLR,
+ scm_sym_enter_frame,
+ stackrep,
+ tail,
+ unmemoize_expression (x, env));
+ SCM_TRAPS_P = 1;
+ if (scm_is_pair (stackrep) &&
+ scm_is_eq (SCM_CAR (stackrep), sym_instead))
+ {
+ /* This gives the possibility for the debugger to modify
+ the source expression before evaluation. */
+ x = SCM_CDR (stackrep);
+ if (SCM_IMP (x))
+ RETURN (x);
+ }
+ }
+ }
+#endif
+dispatch:
+ SCM_TICK;
+ if (SCM_ISYMP (SCM_CAR (x)))
+ {
+ switch (ISYMNUM (SCM_CAR (x)))
+ {
+ case (ISYMNUM (SCM_IM_AND)):
+ x = SCM_CDR (x);
+ while (!scm_is_null (SCM_CDR (x)))
+ {
+ SCM test_result = EVALCAR (x, env);
+ if (scm_is_false (test_result) || SCM_NILP (test_result))
+ RETURN (SCM_BOOL_F);
+ else
+ x = SCM_CDR (x);
+ }
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto carloop;
+
+ case (ISYMNUM (SCM_IM_BEGIN)):
+ x = SCM_CDR (x);
+ if (scm_is_null (x))
+ RETURN (SCM_UNSPECIFIED);
+
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+
+ begin:
+ /* If we are on toplevel with a lookup closure, we need to sync
+ with the current module. */
+ if (scm_is_pair (env) && !scm_is_pair (SCM_CAR (env)))
+ {
+ UPDATE_TOPLEVEL_ENV (env);
+ while (!scm_is_null (SCM_CDR (x)))
+ {
+ EVALCAR (x, env);
+ UPDATE_TOPLEVEL_ENV (env);
+ x = SCM_CDR (x);
+ }
+ goto carloop;
+ }
+ else
+ goto nontoplevel_begin;
+
+ nontoplevel_begin:
+ while (!scm_is_null (SCM_CDR (x)))
+ {
+ const SCM form = SCM_CAR (x);
+ if (SCM_IMP (form))
+ {
+ if (SCM_ISYMP (form))
+ {
+ scm_dynwind_begin (0);
+ scm_i_dynwind_pthread_mutex_lock (&source_mutex);
+ /* check for race condition */
+ if (SCM_ISYMP (SCM_CAR (x)))
+ m_expand_body (x, env);
+ scm_dynwind_end ();
+ goto nontoplevel_begin;
+ }
+ else
+ SCM_VALIDATE_NON_EMPTY_COMBINATION (form);
+ }
+ else
+ (void) EVAL (form, env);
+ x = SCM_CDR (x);
+ }
+
+ carloop:
+ {
+ /* scm_eval last form in list */
+ const SCM last_form = SCM_CAR (x);
+
+ if (scm_is_pair (last_form))
+ {
+ /* This is by far the most frequent case. */
+ x = last_form;
+ goto loop; /* tail recurse */
+ }
+ else if (SCM_IMP (last_form))
+ RETURN (SCM_I_EVALIM (last_form, env));
+ else if (SCM_VARIABLEP (last_form))
+ RETURN (SCM_VARIABLE_REF (last_form));
+ else if (scm_is_symbol (last_form))
+ RETURN (*scm_lookupcar (x, env, 1));
+ else
+ RETURN (last_form);
+ }
+
+
+ case (ISYMNUM (SCM_IM_CASE)):
+ x = SCM_CDR (x);
+ {
+ const SCM key = EVALCAR (x, env);
+ x = SCM_CDR (x);
+ while (!scm_is_null (x))
+ {
+ const SCM clause = SCM_CAR (x);
+ SCM labels = SCM_CAR (clause);
+ if (scm_is_eq (labels, SCM_IM_ELSE))
+ {
+ x = SCM_CDR (clause);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto begin;
+ }
+ while (!scm_is_null (labels))
+ {
+ const SCM label = SCM_CAR (labels);
+ if (scm_is_eq (label, key)
+ || scm_is_true (scm_eqv_p (label, key)))
+ {
+ x = SCM_CDR (clause);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto begin;
+ }
+ labels = SCM_CDR (labels);
+ }
+ x = SCM_CDR (x);
+ }
+ }
+ RETURN (SCM_UNSPECIFIED);
+
+
+ case (ISYMNUM (SCM_IM_COND)):
+ x = SCM_CDR (x);
+ while (!scm_is_null (x))
+ {
+ const SCM clause = SCM_CAR (x);
+ if (scm_is_eq (SCM_CAR (clause), SCM_IM_ELSE))
+ {
+ x = SCM_CDR (clause);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto begin;
+ }
+ else
+ {
+ arg1 = EVALCAR (clause, env);
+ /* SRFI 61 extended cond */
+ if (!scm_is_null (SCM_CDR (clause))
+ && !scm_is_null (SCM_CDDR (clause))
+ && scm_is_eq (SCM_CADDR (clause), SCM_IM_ARROW))
+ {
+ SCM xx, guard_result;
+ if (SCM_VALUESP (arg1))
+ arg1 = scm_struct_ref (arg1, SCM_INUM0);
+ else
+ arg1 = scm_list_1 (arg1);
+ xx = SCM_CDR (clause);
+ proc = EVALCAR (xx, env);
+ guard_result = SCM_APPLY (proc, arg1, SCM_EOL);
+ if (scm_is_true (guard_result)
+ && !SCM_NILP (guard_result))
+ {
+ proc = SCM_CDDR (xx);
+ proc = EVALCAR (proc, env);
+ PREP_APPLY (proc, arg1);
+ goto apply_proc;
+ }
+ }
+ else if (scm_is_true (arg1) && !SCM_NILP (arg1))
+ {
+ x = SCM_CDR (clause);
+ if (scm_is_null (x))
+ RETURN (arg1);
+ else if (!scm_is_eq (SCM_CAR (x), SCM_IM_ARROW))
+ {
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto begin;
+ }
+ else
+ {
+ proc = SCM_CDR (x);
+ proc = EVALCAR (proc, env);
+ PREP_APPLY (proc, scm_list_1 (arg1));
+ ENTER_APPLY;
+ goto evap1;
+ }
+ }
+ x = SCM_CDR (x);
+ }
+ }
+ RETURN (SCM_UNSPECIFIED);
+
+
+ case (ISYMNUM (SCM_IM_DO)):
+ x = SCM_CDR (x);
+ {
+ /* Compute the initialization values and the initial environment. */
+ SCM init_forms = SCM_CAR (x);
+ SCM init_values = SCM_EOL;
+ while (!scm_is_null (init_forms))
+ {
+ init_values = scm_cons (EVALCAR (init_forms, env), init_values);
+ init_forms = SCM_CDR (init_forms);
+ }
+ x = SCM_CDR (x);
+ env = SCM_EXTEND_ENV (SCM_CAR (x), init_values, env);
+ }
+ x = SCM_CDR (x);
+ {
+ SCM test_form = SCM_CAR (x);
+ SCM body_forms = SCM_CADR (x);
+ SCM step_forms = SCM_CDDR (x);
+
+ SCM test_result = EVALCAR (test_form, env);
+
+ while (scm_is_false (test_result) || SCM_NILP (test_result))
+ {
+ {
+ /* Evaluate body forms. */
+ SCM temp_forms;
+ for (temp_forms = body_forms;
+ !scm_is_null (temp_forms);
+ temp_forms = SCM_CDR (temp_forms))
+ {
+ SCM form = SCM_CAR (temp_forms);
+ /* Dirk:FIXME: We only need to eval forms that may have
+ * a side effect here. This is only true for forms that
+ * start with a pair. All others are just constants.
+ * Since with the current memoizer 'form' may hold a
+ * constant, we call EVAL here to handle the constant
+ * cases. In the long run it would make sense to have
+ * the macro transformer of 'do' eliminate all forms
+ * that have no sideeffect. Then instead of EVAL we
+ * could call CEVAL directly here. */
+ (void) EVAL (form, env);
+ }
+ }
+
+ {
+ /* Evaluate the step expressions. */
+ SCM temp_forms;
+ SCM step_values = SCM_EOL;
+ for (temp_forms = step_forms;
+ !scm_is_null (temp_forms);
+ temp_forms = SCM_CDR (temp_forms))
+ {
+ const SCM value = EVALCAR (temp_forms, env);
+ step_values = scm_cons (value, step_values);
+ }
+ env = SCM_EXTEND_ENV (SCM_CAAR (env),
+ step_values,
+ SCM_CDR (env));
+ }
+
+ test_result = EVALCAR (test_form, env);
+ }
+ }
+ x = SCM_CDAR (x);
+ if (scm_is_null (x))
+ RETURN (SCM_UNSPECIFIED);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto nontoplevel_begin;
+
+
+ case (ISYMNUM (SCM_IM_IF)):
+ x = SCM_CDR (x);
+ {
+ SCM test_result = EVALCAR (x, env);
+ x = SCM_CDR (x); /* then expression */
+ if (scm_is_false (test_result) || SCM_NILP (test_result))
+ {
+ x = SCM_CDR (x); /* else expression */
+ if (scm_is_null (x))
+ RETURN (SCM_UNSPECIFIED);
+ }
+ }
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto carloop;
+
+
+ case (ISYMNUM (SCM_IM_LET)):
+ x = SCM_CDR (x);
+ {
+ SCM init_forms = SCM_CADR (x);
+ SCM init_values = SCM_EOL;
+ do
+ {
+ init_values = scm_cons (EVALCAR (init_forms, env), init_values);
+ init_forms = SCM_CDR (init_forms);
+ }
+ while (!scm_is_null (init_forms));
+ env = SCM_EXTEND_ENV (SCM_CAR (x), init_values, env);
+ }
+ x = SCM_CDDR (x);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto nontoplevel_begin;
+
+
+ case (ISYMNUM (SCM_IM_LETREC)):
+ x = SCM_CDR (x);
+ env = SCM_EXTEND_ENV (SCM_CAR (x), undefineds, env);
+ x = SCM_CDR (x);
+ {
+ SCM init_forms = SCM_CAR (x);
+ SCM init_values = scm_list_1 (SCM_BOOL_T);
+ SCM *init_values_eol = SCM_CDRLOC (init_values);
+ eval_letrec_inits (env, init_forms, &init_values_eol);
+ SCM_SETCDR (SCM_CAR (env), SCM_CDR (init_values));
+ }
+ x = SCM_CDR (x);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto nontoplevel_begin;
+
+
+ case (ISYMNUM (SCM_IM_LETSTAR)):
+ x = SCM_CDR (x);
+ {
+ SCM bindings = SCM_CAR (x);
+ if (!scm_is_null (bindings))
+ {
+ do
+ {
+ SCM name = SCM_CAR (bindings);
+ SCM init = SCM_CDR (bindings);
+ env = SCM_EXTEND_ENV (name, EVALCAR (init, env), env);
+ bindings = SCM_CDR (init);
+ }
+ while (!scm_is_null (bindings));
+ }
+ }
+ x = SCM_CDR (x);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto nontoplevel_begin;
+
+
+ case (ISYMNUM (SCM_IM_OR)):
+ x = SCM_CDR (x);
+ while (!scm_is_null (SCM_CDR (x)))
+ {
+ SCM val = EVALCAR (x, env);
+ if (scm_is_true (val) && !SCM_NILP (val))
+ RETURN (val);
+ else
+ x = SCM_CDR (x);
+ }
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto carloop;
+
+
+ case (ISYMNUM (SCM_IM_LAMBDA)):
+ RETURN (scm_closure (SCM_CDR (x), env));
+
+
+ case (ISYMNUM (SCM_IM_QUOTE)):
+ RETURN (SCM_CDR (x));
+
+
+ case (ISYMNUM (SCM_IM_SET_X)):
+ x = SCM_CDR (x);
+ {
+ SCM *location;
+ SCM variable = SCM_CAR (x);
+ if (SCM_ILOCP (variable))
+ location = scm_ilookup (variable, env);
+ else if (SCM_VARIABLEP (variable))
+ location = SCM_VARIABLE_LOC (variable);
+ else
+ {
+ /* (scm_is_symbol (variable)) is known to be true */
+ variable = lazy_memoize_variable (variable, env);
+ SCM_SETCAR (x, variable);
+ location = SCM_VARIABLE_LOC (variable);
+ }
+ x = SCM_CDR (x);
+ *location = EVALCAR (x, env);
+ }
+ RETURN (SCM_UNSPECIFIED);
+
+
+ case (ISYMNUM (SCM_IM_APPLY)):
+ /* Evaluate the procedure to be applied. */
+ x = SCM_CDR (x);
+ proc = EVALCAR (x, env);
+ PREP_APPLY (proc, SCM_EOL);
+
+ /* Evaluate the argument holding the list of arguments */
+ x = SCM_CDR (x);
+ arg1 = EVALCAR (x, env);
+
+ apply_proc:
+ /* Go here to tail-apply a procedure. PROC is the procedure and
+ * ARG1 is the list of arguments. PREP_APPLY must have been called
+ * before jumping to apply_proc. */
+ if (SCM_CLOSUREP (proc))
+ {
+ SCM formals = SCM_CLOSURE_FORMALS (proc);
+#ifdef DEVAL
+ debug.info->a.args = arg1;
+#endif
+ if (SCM_UNLIKELY (scm_badargsp (formals, arg1)))
+ scm_wrong_num_args (proc);
+ ENTER_APPLY;
+ /* Copy argument list */
+ if (SCM_NULL_OR_NIL_P (arg1))
+ env = SCM_EXTEND_ENV (formals, SCM_EOL, SCM_ENV (proc));
+ else
+ {
+ SCM args = scm_list_1 (SCM_CAR (arg1));
+ SCM tail = args;
+ arg1 = SCM_CDR (arg1);
+ while (!SCM_NULL_OR_NIL_P (arg1))
+ {
+ SCM new_tail = scm_list_1 (SCM_CAR (arg1));
+ SCM_SETCDR (tail, new_tail);
+ tail = new_tail;
+ arg1 = SCM_CDR (arg1);
+ }
+ env = SCM_EXTEND_ENV (formals, args, SCM_ENV (proc));
+ }
+
+ x = SCM_CLOSURE_BODY (proc);
+ goto nontoplevel_begin;
+ }
+ else
+ {
+ ENTER_APPLY;
+ RETURN (SCM_APPLY (proc, arg1, SCM_EOL));
+ }
+
+
+ case (ISYMNUM (SCM_IM_CONT)):
+ {
+ int first;
+ SCM val = scm_make_continuation (&first);
+
+ if (!first)
+ RETURN (val);
+ else
+ {
+ arg1 = val;
+ proc = SCM_CDR (x);
+ proc = EVALCAR (proc, env);
+ PREP_APPLY (proc, scm_list_1 (arg1));
+ ENTER_APPLY;
+ goto evap1;
+ }
+ }
+
+
+ case (ISYMNUM (SCM_IM_DELAY)):
+ RETURN (scm_makprom (scm_closure (SCM_CDR (x), env)));
+
+#if 0
+ /* See futures.h for a comment why futures are not enabled.
+ */
+ case (ISYMNUM (SCM_IM_FUTURE)):
+ RETURN (scm_i_make_future (scm_closure (SCM_CDR (x), env)));
+#endif
+
+ /* PLACEHOLDER for case (ISYMNUM (SCM_IM_DISPATCH)): The following
+ code (type_dispatch) is intended to be the tail of the case
+ clause for the internal macro SCM_IM_DISPATCH. Please don't
+ remove it from this location without discussing it with Mikael
+ <djurfeldt@nada.kth.se> */
+
+ /* The type dispatch code is duplicated below
+ * (c.f. objects.c:scm_mcache_compute_cmethod) since that
+ * cuts down execution time for type dispatch to 50%. */
+ type_dispatch: /* inputs: x, arg1 */
+ /* Type dispatch means to determine from the types of the function
+ * arguments (i. e. the 'signature' of the call), which method from
+ * a generic function is to be called. This process of selecting
+ * the right method takes some time. To speed it up, guile uses
+ * caching: Together with the macro call to dispatch the signatures
+ * of some previous calls to that generic function from the same
+ * place are stored (in the code!) in a cache that we call the
+ * 'method cache'. This is done since it is likely, that
+ * consecutive calls to dispatch from that position in the code will
+ * have the same signature. Thus, the type dispatch works as
+ * follows: First, determine a hash value from the signature of the
+ * actual arguments. Second, use this hash value as an index to
+ * find that same signature in the method cache stored at this
+ * position in the code. If found, you have also found the
+ * corresponding method that belongs to that signature. If the
+ * signature is not found in the method cache, you have to perform a
+ * full search over all signatures stored with the generic
+ * function. */
+ {
+ unsigned long int specializers;
+ unsigned long int hash_value;
+ unsigned long int cache_end_pos;
+ unsigned long int mask;
+ SCM method_cache;
+
+ {
+ SCM z = SCM_CDDR (x);
+ SCM tmp = SCM_CADR (z);
+ specializers = scm_to_ulong (SCM_CAR (z));
+
+ /* Compute a hash value for searching the method cache. There
+ * are two variants for computing the hash value, a (rather)
+ * complicated one, and a simple one. For the complicated one
+ * explained below, tmp holds a number that is used in the
+ * computation. */
+ if (scm_is_simple_vector (tmp))
+ {
+ /* This method of determining the hash value is much
+ * simpler: Set the hash value to zero and just perform a
+ * linear search through the method cache. */
+ method_cache = tmp;
+ mask = (unsigned long int) ((long) -1);
+ hash_value = 0;
+ cache_end_pos = SCM_SIMPLE_VECTOR_LENGTH (method_cache);
+ }
+ else
+ {
+ /* Use the signature of the actual arguments to determine
+ * the hash value. This is done as follows: Each class has
+ * an array of random numbers, that are determined when the
+ * class is created. The integer 'hashset' is an index into
+ * that array of random numbers. Now, from all classes that
+ * are part of the signature of the actual arguments, the
+ * random numbers at index 'hashset' are taken and summed
+ * up, giving the hash value. The value of 'hashset' is
+ * stored at the call to dispatch. This allows to have
+ * different 'formulas' for calculating the hash value at
+ * different places where dispatch is called. This allows
+ * to optimize the hash formula at every individual place
+ * where dispatch is called, such that hopefully the hash
+ * value that is computed will directly point to the right
+ * method in the method cache. */
+ unsigned long int hashset = scm_to_ulong (tmp);
+ unsigned long int counter = specializers + 1;
+ SCM tmp_arg = arg1;
+ hash_value = 0;
+ while (!scm_is_null (tmp_arg) && counter != 0)
+ {
+ SCM class = scm_class_of (SCM_CAR (tmp_arg));
+ hash_value += SCM_INSTANCE_HASH (class, hashset);
+ tmp_arg = SCM_CDR (tmp_arg);
+ counter--;
+ }
+ z = SCM_CDDR (z);
+ method_cache = SCM_CADR (z);
+ mask = scm_to_ulong (SCM_CAR (z));
+ hash_value &= mask;
+ cache_end_pos = hash_value;
+ }
+ }
+
+ {
+ /* Search the method cache for a method with a matching
+ * signature. Start the search at position 'hash_value'. The
+ * hashing implementation uses linear probing for conflict
+ * resolution, that is, if the signature in question is not
+ * found at the starting index in the hash table, the next table
+ * entry is tried, and so on, until in the worst case the whole
+ * cache has been searched, but still the signature has not been
+ * found. */
+ SCM z;
+ do
+ {
+ SCM args = arg1; /* list of arguments */
+ z = SCM_SIMPLE_VECTOR_REF (method_cache, hash_value);
+ while (!scm_is_null (args))
+ {
+ /* More arguments than specifiers => CLASS != ENV */
+ SCM class_of_arg = scm_class_of (SCM_CAR (args));
+ if (!scm_is_eq (class_of_arg, SCM_CAR (z)))
+ goto next_method;
+ args = SCM_CDR (args);
+ z = SCM_CDR (z);
+ }
+ /* Fewer arguments than specifiers => CAR != ENV */
+ if (scm_is_null (SCM_CAR (z)) || scm_is_pair (SCM_CAR (z)))
+ goto apply_cmethod;
+ next_method:
+ hash_value = (hash_value + 1) & mask;
+ } while (hash_value != cache_end_pos);
+
+ /* No appropriate method was found in the cache. */
+ z = scm_memoize_method (x, arg1);
+
+ apply_cmethod: /* inputs: z, arg1 */
+ {
+ SCM formals = SCM_CMETHOD_FORMALS (z);
+ env = SCM_EXTEND_ENV (formals, arg1, SCM_CMETHOD_ENV (z));
+ x = SCM_CMETHOD_BODY (z);
+ goto nontoplevel_begin;
+ }
+ }
+ }
+
+
+ case (ISYMNUM (SCM_IM_SLOT_REF)):
+ x = SCM_CDR (x);
+ {
+ SCM instance = EVALCAR (x, env);
+ unsigned long int slot = SCM_I_INUM (SCM_CDR (x));
+ RETURN (SCM_PACK (SCM_STRUCT_DATA (instance) [slot]));
+ }
+
+
+ case (ISYMNUM (SCM_IM_SLOT_SET_X)):
+ x = SCM_CDR (x);
+ {
+ SCM instance = EVALCAR (x, env);
+ unsigned long int slot = SCM_I_INUM (SCM_CADR (x));
+ SCM value = EVALCAR (SCM_CDDR (x), env);
+ SCM_STRUCT_DATA (instance) [slot] = SCM_UNPACK (value);
+ RETURN (SCM_UNSPECIFIED);
+ }
+
+
+#if SCM_ENABLE_ELISP
+
+ case (ISYMNUM (SCM_IM_NIL_COND)):
+ {
+ SCM test_form = SCM_CDR (x);
+ x = SCM_CDR (test_form);
+ while (!SCM_NULL_OR_NIL_P (x))
+ {
+ SCM test_result = EVALCAR (test_form, env);
+ if (!(scm_is_false (test_result)
+ || SCM_NULL_OR_NIL_P (test_result)))
+ {
+ if (scm_is_eq (SCM_CAR (x), SCM_UNSPECIFIED))
+ RETURN (test_result);
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto carloop;
+ }
+ else
+ {
+ test_form = SCM_CDR (x);
+ x = SCM_CDR (test_form);
+ }
+ }
+ x = test_form;
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto carloop;
+ }
+
+#endif /* SCM_ENABLE_ELISP */
+
+ case (ISYMNUM (SCM_IM_BIND)):
+ {
+ SCM vars, exps, vals;
+
+ x = SCM_CDR (x);
+ vars = SCM_CAAR (x);
+ exps = SCM_CDAR (x);
+ vals = SCM_EOL;
+ while (!scm_is_null (exps))
+ {
+ vals = scm_cons (EVALCAR (exps, env), vals);
+ exps = SCM_CDR (exps);
+ }
+
+ scm_swap_bindings (vars, vals);
+ scm_i_set_dynwinds (scm_acons (vars, vals, scm_i_dynwinds ()));
+
+ /* Ignore all but the last evaluation result. */
+ for (x = SCM_CDR (x); !scm_is_null (SCM_CDR (x)); x = SCM_CDR (x))
+ {
+ if (scm_is_pair (SCM_CAR (x)))
+ CEVAL (SCM_CAR (x), env);
+ }
+ proc = EVALCAR (x, env);
+
+ scm_i_set_dynwinds (SCM_CDR (scm_i_dynwinds ()));
+ scm_swap_bindings (vars, vals);
+
+ RETURN (proc);
+ }
+
+
+ case (ISYMNUM (SCM_IM_CALL_WITH_VALUES)):
+ {
+ SCM producer;
+
+ x = SCM_CDR (x);
+ producer = EVALCAR (x, env);
+ x = SCM_CDR (x);
+ proc = EVALCAR (x, env); /* proc is the consumer. */
+ arg1 = SCM_APPLY (producer, SCM_EOL, SCM_EOL);
+ if (SCM_VALUESP (arg1))
+ {
+ /* The list of arguments is not copied. Rather, it is assumed
+ * that this has been done by the 'values' procedure. */
+ arg1 = scm_struct_ref (arg1, SCM_INUM0);
+ }
+ else
+ {
+ arg1 = scm_list_1 (arg1);
+ }
+ PREP_APPLY (proc, arg1);
+ goto apply_proc;
+ }
+
+
+ default:
+ break;
+ }
+ }
+ else
+ {
+ if (SCM_VARIABLEP (SCM_CAR (x)))
+ proc = SCM_VARIABLE_REF (SCM_CAR (x));
+ else if (SCM_ILOCP (SCM_CAR (x)))
+ proc = *scm_ilookup (SCM_CAR (x), env);
+ else if (scm_is_pair (SCM_CAR (x)))
+ proc = CEVAL (SCM_CAR (x), env);
+ else if (scm_is_symbol (SCM_CAR (x)))
+ {
+ SCM orig_sym = SCM_CAR (x);
+ {
+ SCM *location = scm_lookupcar1 (x, env, 1);
+ if (location == NULL)
+ {
+ /* we have lost the race, start again. */
+ goto dispatch;
+ }
+ proc = *location;
+ }
+
+ if (SCM_MACROP (proc))
+ {
+ SCM_SETCAR (x, orig_sym); /* Undo memoizing effect of
+ lookupcar */
+ handle_a_macro: /* inputs: x, env, proc */
+#ifdef DEVAL
+ /* Set a flag during macro expansion so that macro
+ application frames can be deleted from the backtrace. */
+ SCM_SET_MACROEXP (debug);
+#endif
+ arg1 = SCM_APPLY (SCM_MACRO_CODE (proc), x,
+ scm_cons (env, scm_listofnull));
+#ifdef DEVAL
+ SCM_CLEAR_MACROEXP (debug);
+#endif
+ switch (SCM_MACRO_TYPE (proc))
+ {
+ case 3:
+ case 2:
+ if (!scm_is_pair (arg1))
+ arg1 = scm_list_2 (SCM_IM_BEGIN, arg1);
+
+ assert (!scm_is_eq (x, SCM_CAR (arg1))
+ && !scm_is_eq (x, SCM_CDR (arg1)));
+
+#ifdef DEVAL
+ if (!SCM_CLOSUREP (SCM_MACRO_CODE (proc)))
+ {
+ SCM_CRITICAL_SECTION_START;
+ SCM_SETCAR (x, SCM_CAR (arg1));
+ SCM_SETCDR (x, SCM_CDR (arg1));
+ SCM_CRITICAL_SECTION_END;
+ goto dispatch;
+ }
+ /* Prevent memoizing of debug info expression. */
+ debug.info->e.exp = scm_cons_source (debug.info->e.exp,
+ SCM_CAR (x),
+ SCM_CDR (x));
+#endif
+ SCM_CRITICAL_SECTION_START;
+ SCM_SETCAR (x, SCM_CAR (arg1));
+ SCM_SETCDR (x, SCM_CDR (arg1));
+ SCM_CRITICAL_SECTION_END;
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto loop;
+#if SCM_ENABLE_DEPRECATED == 1
+ case 1:
+ x = arg1;
+ if (SCM_NIMP (x))
+ {
+ PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
+ goto loop;
+ }
+ else
+ RETURN (arg1);
+#endif
+ case 0:
+ RETURN (arg1);
+ }
+ }
+ }
+ else
+ proc = SCM_CAR (x);
+
+ if (SCM_MACROP (proc))
+ goto handle_a_macro;
+ }
+
+
+ /* When reaching this part of the code, the following is granted: Variable x
+ * holds the first pair of an expression of the form (<function> arg ...).
+ * Variable proc holds the object that resulted from the evaluation of
+ * <function>. In the following, the arguments (if any) will be evaluated,
+ * and proc will be applied to them. If proc does not really hold a
+ * function object, this will be signalled as an error on the scheme
+ * level. If the number of arguments does not match the number of arguments
+ * that are allowed to be passed to proc, also an error on the scheme level
+ * will be signalled. */
+ PREP_APPLY (proc, SCM_EOL);
+ if (scm_is_null (SCM_CDR (x))) {
+ ENTER_APPLY;
+ evap0:
+ SCM_ASRTGO (!SCM_IMP (proc), badfun);
+ switch (SCM_TYP7 (proc))
+ { /* no arguments given */
+ case scm_tc7_subr_0:
+ RETURN (SCM_SUBRF (proc) ());
+ case scm_tc7_subr_1o:
+ RETURN (SCM_SUBRF (proc) (SCM_UNDEFINED));
+ case scm_tc7_lsubr:
+ RETURN (SCM_SUBRF (proc) (SCM_EOL));
+ case scm_tc7_rpsubr:
+ RETURN (SCM_BOOL_T);
+ case scm_tc7_asubr:
+ RETURN (SCM_SUBRF (proc) (SCM_UNDEFINED, SCM_UNDEFINED));
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badfun;
+ RETURN (SCM_SMOB_APPLY_0 (proc));
+ case scm_tc7_cclo:
+ arg1 = proc;
+ proc = SCM_CCLO_SUBR (proc);
+#ifdef DEVAL
+ debug.info->a.proc = proc;
+ debug.info->a.args = scm_list_1 (arg1);
+#endif
+ goto evap1;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+#ifdef DEVAL
+ debug.info->a.proc = proc;
+#endif
+ if (!SCM_CLOSUREP (proc))
+ goto evap0;
+ /* fallthrough */
+ case scm_tcs_closures:
+ {
+ const SCM formals = SCM_CLOSURE_FORMALS (proc);
+ if (SCM_UNLIKELY (scm_is_pair (formals)))
+ goto wrongnumargs;
+ x = SCM_CLOSURE_BODY (proc);
+ env = SCM_EXTEND_ENV (formals, SCM_EOL, SCM_ENV (proc));
+ goto nontoplevel_begin;
+ }
+ case scm_tcs_struct:
+ if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
+ {
+ x = SCM_ENTITY_PROCEDURE (proc);
+ arg1 = SCM_EOL;
+ goto type_dispatch;
+ }
+ else if (SCM_I_OPERATORP (proc))
+ {
+ arg1 = proc;
+ proc = (SCM_I_ENTITYP (proc)
+ ? SCM_ENTITY_PROCEDURE (proc)
+ : SCM_OPERATOR_PROCEDURE (proc));
+#ifdef DEVAL
+ debug.info->a.proc = proc;
+ debug.info->a.args = scm_list_1 (arg1);
+#endif
+ goto evap1;
+ }
+ else
+ goto badfun;
+ case scm_tc7_subr_1:
+ case scm_tc7_subr_2:
+ case scm_tc7_subr_2o:
+ case scm_tc7_dsubr:
+ case scm_tc7_cxr:
+ case scm_tc7_subr_3:
+ case scm_tc7_lsubr_2:
+ wrongnumargs:
+ scm_wrong_num_args (proc);
+ default:
+ badfun:
+ scm_misc_error (NULL, "Wrong type to apply: ~S", scm_list_1 (proc));
+ }
+ }
+
+ /* must handle macros by here */
+ x = SCM_CDR (x);
+ if (SCM_LIKELY (scm_is_pair (x)))
+ arg1 = EVALCAR (x, env);
+ else
+ scm_wrong_num_args (proc);
+#ifdef DEVAL
+ debug.info->a.args = scm_list_1 (arg1);
+#endif
+ x = SCM_CDR (x);
+ {
+ SCM arg2;
+ if (scm_is_null (x))
+ {
+ ENTER_APPLY;
+ evap1: /* inputs: proc, arg1 */
+ SCM_ASRTGO (!SCM_IMP (proc), badfun);
+ switch (SCM_TYP7 (proc))
+ { /* have one argument in arg1 */
+ case scm_tc7_subr_2o:
+ RETURN (SCM_SUBRF (proc) (arg1, SCM_UNDEFINED));
+ case scm_tc7_subr_1:
+ case scm_tc7_subr_1o:
+ RETURN (SCM_SUBRF (proc) (arg1));
+ case scm_tc7_dsubr:
+ 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)));
+ case scm_tc7_cxr:
+ RETURN (scm_i_chase_pairs (arg1, (scm_t_bits) SCM_SUBRF (proc)));
+ case scm_tc7_rpsubr:
+ RETURN (SCM_BOOL_T);
+ case scm_tc7_asubr:
+ RETURN (SCM_SUBRF (proc) (arg1, SCM_UNDEFINED));
+ case scm_tc7_lsubr:
+#ifdef DEVAL
+ RETURN (SCM_SUBRF (proc) (debug.info->a.args));
+#else
+ RETURN (SCM_SUBRF (proc) (scm_list_1 (arg1)));
+#endif
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badfun;
+ RETURN (SCM_SMOB_APPLY_1 (proc, arg1));
+ case scm_tc7_cclo:
+ arg2 = arg1;
+ arg1 = proc;
+ proc = SCM_CCLO_SUBR (proc);
+#ifdef DEVAL
+ debug.info->a.args = scm_cons (arg1, debug.info->a.args);
+ debug.info->a.proc = proc;
+#endif
+ goto evap2;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+#ifdef DEVAL
+ debug.info->a.proc = proc;
+#endif
+ if (!SCM_CLOSUREP (proc))
+ goto evap1;
+ /* fallthrough */
+ case scm_tcs_closures:
+ {
+ /* clos1: */
+ const SCM formals = SCM_CLOSURE_FORMALS (proc);
+ if (SCM_UNLIKELY (scm_is_null (formals)
+ || (scm_is_pair (formals) &&
+ scm_is_pair (SCM_CDR (formals)))))
+ goto wrongnumargs;
+ x = SCM_CLOSURE_BODY (proc);
+#ifdef DEVAL
+ env = SCM_EXTEND_ENV (formals,
+ debug.info->a.args,
+ SCM_ENV (proc));
+#else
+ env = SCM_EXTEND_ENV (formals,
+ scm_list_1 (arg1),
+ SCM_ENV (proc));
+#endif
+ goto nontoplevel_begin;
+ }
+ case scm_tcs_struct:
+ if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
+ {
+ x = SCM_ENTITY_PROCEDURE (proc);
+#ifdef DEVAL
+ arg1 = debug.info->a.args;
+#else
+ arg1 = scm_list_1 (arg1);
+#endif
+ goto type_dispatch;
+ }
+ else if (SCM_I_OPERATORP (proc))
+ {
+ arg2 = arg1;
+ arg1 = proc;
+ proc = (SCM_I_ENTITYP (proc)
+ ? SCM_ENTITY_PROCEDURE (proc)
+ : SCM_OPERATOR_PROCEDURE (proc));
+#ifdef DEVAL
+ debug.info->a.args = scm_cons (arg1, debug.info->a.args);
+ debug.info->a.proc = proc;
+#endif
+ goto evap2;
+ }
+ else
+ goto badfun;
+ case scm_tc7_subr_2:
+ case scm_tc7_subr_0:
+ case scm_tc7_subr_3:
+ case scm_tc7_lsubr_2:
+ scm_wrong_num_args (proc);
+ default:
+ goto badfun;
+ }
+ }
+ if (SCM_LIKELY (scm_is_pair (x)))
+ arg2 = EVALCAR (x, env);
+ else
+ scm_wrong_num_args (proc);
+
+ { /* have two or more arguments */
+#ifdef DEVAL
+ debug.info->a.args = scm_list_2 (arg1, arg2);
+#endif
+ x = SCM_CDR (x);
+ if (scm_is_null (x)) {
+ ENTER_APPLY;
+ evap2:
+ SCM_ASRTGO (!SCM_IMP (proc), badfun);
+ switch (SCM_TYP7 (proc))
+ { /* have two arguments */
+ case scm_tc7_subr_2:
+ case scm_tc7_subr_2o:
+ RETURN (SCM_SUBRF (proc) (arg1, arg2));
+ case scm_tc7_lsubr:
+#ifdef DEVAL
+ RETURN (SCM_SUBRF (proc) (debug.info->a.args));
+#else
+ RETURN (SCM_SUBRF (proc) (scm_list_2 (arg1, arg2)));
+#endif
+ case scm_tc7_lsubr_2:
+ RETURN (SCM_SUBRF (proc) (arg1, arg2, SCM_EOL));
+ case scm_tc7_rpsubr:
+ case scm_tc7_asubr:
+ RETURN (SCM_SUBRF (proc) (arg1, arg2));
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badfun;
+ RETURN (SCM_SMOB_APPLY_2 (proc, arg1, arg2));
+ cclon:
+ case scm_tc7_cclo:
+#ifdef DEVAL
+ RETURN (SCM_APPLY (SCM_CCLO_SUBR (proc),
+ scm_cons (proc, debug.info->a.args),
+ SCM_EOL));
+#else
+ RETURN (SCM_APPLY (SCM_CCLO_SUBR (proc),
+ scm_cons2 (proc, arg1,
+ scm_cons (arg2,
+ scm_eval_args (x,
+ env,
+ proc))),
+ SCM_EOL));
+#endif
+ case scm_tcs_struct:
+ if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
+ {
+ x = SCM_ENTITY_PROCEDURE (proc);
+#ifdef DEVAL
+ arg1 = debug.info->a.args;
+#else
+ arg1 = scm_list_2 (arg1, arg2);
+#endif
+ goto type_dispatch;
+ }
+ else if (SCM_I_OPERATORP (proc))
+ {
+ operatorn:
+#ifdef DEVAL
+ RETURN (SCM_APPLY (SCM_I_ENTITYP (proc)
+ ? SCM_ENTITY_PROCEDURE (proc)
+ : SCM_OPERATOR_PROCEDURE (proc),
+ scm_cons (proc, debug.info->a.args),
+ SCM_EOL));
+#else
+ RETURN (SCM_APPLY (SCM_I_ENTITYP (proc)
+ ? SCM_ENTITY_PROCEDURE (proc)
+ : SCM_OPERATOR_PROCEDURE (proc),
+ scm_cons2 (proc, arg1,
+ scm_cons (arg2,
+ scm_eval_args (x,
+ env,
+ proc))),
+ SCM_EOL));
+#endif
+ }
+ else
+ goto badfun;
+ case scm_tc7_subr_0:
+ case scm_tc7_dsubr:
+ case scm_tc7_cxr:
+ case scm_tc7_subr_1o:
+ case scm_tc7_subr_1:
+ case scm_tc7_subr_3:
+ scm_wrong_num_args (proc);
+ default:
+ goto badfun;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+#ifdef DEVAL
+ debug.info->a.proc = proc;
+#endif
+ if (!SCM_CLOSUREP (proc))
+ goto evap2;
+ /* fallthrough */
+ case scm_tcs_closures:
+ {
+ /* clos2: */
+ const SCM formals = SCM_CLOSURE_FORMALS (proc);
+ if (SCM_UNLIKELY
+ (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)))))))
+ goto wrongnumargs;
+#ifdef DEVAL
+ env = SCM_EXTEND_ENV (formals,
+ debug.info->a.args,
+ SCM_ENV (proc));
+#else
+ env = SCM_EXTEND_ENV (formals,
+ scm_list_2 (arg1, arg2),
+ SCM_ENV (proc));
+#endif
+ x = SCM_CLOSURE_BODY (proc);
+ goto nontoplevel_begin;
+ }
+ }
+ }
+ if (SCM_UNLIKELY (!scm_is_pair (x)))
+ scm_wrong_num_args (proc);
+#ifdef DEVAL
+ debug.info->a.args = scm_cons2 (arg1, arg2,
+ deval_args (x, env, proc,
+ SCM_CDRLOC (SCM_CDR (debug.info->a.args))));
+#endif
+ ENTER_APPLY;
+ evap3:
+ SCM_ASRTGO (!SCM_IMP (proc), badfun);
+ switch (SCM_TYP7 (proc))
+ { /* have 3 or more arguments */
+#ifdef DEVAL
+ case scm_tc7_subr_3:
+ if (SCM_UNLIKELY (!scm_is_null (SCM_CDR (x))))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) (arg1, arg2,
+ SCM_CADDR (debug.info->a.args)));
+ case scm_tc7_asubr:
+ arg1 = SCM_SUBRF(proc)(arg1, arg2);
+ arg2 = SCM_CDDR (debug.info->a.args);
+ do
+ {
+ arg1 = SCM_SUBRF(proc)(arg1, SCM_CAR (arg2));
+ arg2 = SCM_CDR (arg2);
+ }
+ while (SCM_NIMP (arg2));
+ RETURN (arg1);
+ case scm_tc7_rpsubr:
+ if (scm_is_false (SCM_SUBRF (proc) (arg1, arg2)))
+ RETURN (SCM_BOOL_F);
+ arg1 = SCM_CDDR (debug.info->a.args);
+ do
+ {
+ if (scm_is_false (SCM_SUBRF (proc) (arg2, SCM_CAR (arg1))))
+ RETURN (SCM_BOOL_F);
+ arg2 = SCM_CAR (arg1);
+ arg1 = SCM_CDR (arg1);
+ }
+ while (SCM_NIMP (arg1));
+ RETURN (SCM_BOOL_T);
+ case scm_tc7_lsubr_2:
+ RETURN (SCM_SUBRF (proc) (arg1, arg2,
+ SCM_CDDR (debug.info->a.args)));
+ case scm_tc7_lsubr:
+ RETURN (SCM_SUBRF (proc) (debug.info->a.args));
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badfun;
+ RETURN (SCM_SMOB_APPLY_3 (proc, arg1, arg2,
+ SCM_CDDR (debug.info->a.args)));
+ case scm_tc7_cclo:
+ goto cclon;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+ debug.info->a.proc = proc;
+ if (!SCM_CLOSUREP (proc))
+ goto evap3;
+ /* fallthrough */
+ case scm_tcs_closures:
+ {
+ const 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_badargsp (SCM_CDDR (formals), x)))))
+ goto wrongnumargs;
+ SCM_SET_ARGSREADY (debug);
+ env = SCM_EXTEND_ENV (formals,
+ debug.info->a.args,
+ SCM_ENV (proc));
+ x = SCM_CLOSURE_BODY (proc);
+ goto nontoplevel_begin;
+ }
+#else /* DEVAL */
+ case scm_tc7_subr_3:
+ if (SCM_UNLIKELY (!scm_is_null (SCM_CDR (x))))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) (arg1, arg2, EVALCAR (x, env)));
+ case scm_tc7_asubr:
+ arg1 = SCM_SUBRF (proc) (arg1, arg2);
+ do
+ {
+ arg1 = SCM_SUBRF(proc)(arg1, EVALCAR(x, env));
+ x = SCM_CDR(x);
+ }
+ while (!scm_is_null (x));
+ RETURN (arg1);
+ case scm_tc7_rpsubr:
+ if (scm_is_false (SCM_SUBRF (proc) (arg1, arg2)))
+ RETURN (SCM_BOOL_F);
+ do
+ {
+ arg1 = EVALCAR (x, env);
+ if (scm_is_false (SCM_SUBRF (proc) (arg2, arg1)))
+ RETURN (SCM_BOOL_F);
+ arg2 = arg1;
+ x = SCM_CDR (x);
+ }
+ while (!scm_is_null (x));
+ RETURN (SCM_BOOL_T);
+ case scm_tc7_lsubr_2:
+ RETURN (SCM_SUBRF (proc) (arg1, arg2, scm_eval_args (x, env, proc)));
+ case scm_tc7_lsubr:
+ RETURN (SCM_SUBRF (proc) (scm_cons2 (arg1,
+ arg2,
+ scm_eval_args (x, env, proc))));
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badfun;
+ RETURN (SCM_SMOB_APPLY_3 (proc, arg1, arg2,
+ scm_eval_args (x, env, proc)));
+ case scm_tc7_cclo:
+ goto cclon;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+ if (!SCM_CLOSUREP (proc))
+ goto evap3;
+ /* fallthrough */
+ case scm_tcs_closures:
+ {
+ const 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_badargsp (SCM_CDDR (formals), x)))))
+ goto wrongnumargs;
+ env = SCM_EXTEND_ENV (formals,
+ scm_cons2 (arg1,
+ arg2,
+ scm_eval_args (x, env, proc)),
+ SCM_ENV (proc));
+ x = SCM_CLOSURE_BODY (proc);
+ goto nontoplevel_begin;
+ }
+#endif /* DEVAL */
+ case scm_tcs_struct:
+ if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
+ {
+#ifdef DEVAL
+ arg1 = debug.info->a.args;
+#else
+ arg1 = scm_cons2 (arg1, arg2, scm_eval_args (x, env, proc));
+#endif
+ x = SCM_ENTITY_PROCEDURE (proc);
+ goto type_dispatch;
+ }
+ else if (SCM_I_OPERATORP (proc))
+ goto operatorn;
+ else
+ goto badfun;
+ case scm_tc7_subr_2:
+ case scm_tc7_subr_1o:
+ case scm_tc7_subr_2o:
+ case scm_tc7_subr_0:
+ case scm_tc7_dsubr:
+ case scm_tc7_cxr:
+ case scm_tc7_subr_1:
+ scm_wrong_num_args (proc);
+ default:
+ goto badfun;
+ }
+ }
+ }
+#ifdef DEVAL
+exit:
+ if (scm_check_exit_p && SCM_TRAPS_P)
+ if (SCM_EXIT_FRAME_P || (SCM_TRACE_P && SCM_TRACED_FRAME_P (debug)))
+ {
+ SCM_CLEAR_TRACED_FRAME (debug);
+ arg1 = scm_make_debugobj (&debug);
+ SCM_TRAPS_P = 0;
+ arg1 = scm_call_3 (SCM_EXIT_FRAME_HDLR, scm_sym_exit_frame, arg1, proc);
+ SCM_TRAPS_P = 1;
+ if (scm_is_pair (arg1) && scm_is_eq (SCM_CAR (arg1), sym_instead))
+ proc = SCM_CDR (arg1);
+ }
+ scm_i_set_last_debug_frame (debug.prev);
+ return proc;
+#endif
+}
+
+
+/* SECTION: This code is compiled once.
+ */
+
+#ifndef DEVAL
+
+\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
+
+#endif /* !DEVAL */
+
+
+/* SECTION: When DEVAL is defined this code yields scm_dapply.
+ * It is compiled twice.
+ */
+
+#if 0
+SCM
+scm_apply (SCM proc, SCM arg1, SCM args)
+{}
+#endif
+
+#if 0
+SCM
+scm_dapply (SCM proc, SCM arg1, SCM args)
+{}
+#endif
+
+
+/* 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)
+{
+#ifdef DEVAL
+ scm_t_debug_frame debug;
+ scm_t_debug_info debug_vect_body;
+ debug.prev = scm_i_last_debug_frame ();
+ debug.status = SCM_APPLYFRAME;
+ debug.vect = &debug_vect_body;
+ debug.vect[0].a.proc = proc;
+ debug.vect[0].a.args = SCM_EOL;
+ scm_i_set_last_debug_frame (&debug);
+#else
+ if (scm_debug_mode_p)
+ return scm_dapply (proc, arg1, args);
+#endif
+
+ SCM_ASRTGO (SCM_NIMP (proc), badproc);
+
+ /* If ARGS is the empty list, then we're calling apply with only two
+ arguments --- ARG1 is the list of arguments for PROC. Whatever
+ the case, futz with things so that ARG1 is the first argument to
+ give to PROC (or SCM_UNDEFINED if no args), and ARGS contains the
+ rest.
+
+ Setting the debug apply frame args this way is pretty messy.
+ Perhaps we should store arg1 and args directly in the frame as
+ received, and let scm_frame_arguments unpack them, because that's
+ a relatively rare operation. This works for now; if the Guile
+ developer archives are still around, see Mikael's post of
+ 11-Apr-97. */
+ if (scm_is_null (args))
+ {
+ if (scm_is_null (arg1))
+ {
+ arg1 = SCM_UNDEFINED;
+#ifdef DEVAL
+ debug.vect[0].a.args = SCM_EOL;
+#endif
+ }
+ else
+ {
+#ifdef DEVAL
+ debug.vect[0].a.args = arg1;
+#endif
+ args = SCM_CDR (arg1);
+ arg1 = SCM_CAR (arg1);
+ }
+ }
+ else
+ {
+ args = scm_nconc2last (args);
+#ifdef DEVAL
+ debug.vect[0].a.args = scm_cons (arg1, args);
+#endif
+ }
+#ifdef DEVAL
+ if (SCM_ENTER_FRAME_P && SCM_TRAPS_P)
+ {
+ SCM tmp = scm_make_debugobj (&debug);
+ SCM_TRAPS_P = 0;
+ scm_call_2 (SCM_ENTER_FRAME_HDLR, scm_sym_enter_frame, tmp);
+ SCM_TRAPS_P = 1;
+ }
+ ENTER_APPLY;
+#endif
+tail:
+ switch (SCM_TYP7 (proc))
+ {
+ case scm_tc7_subr_2o:
+ if (SCM_UNLIKELY (SCM_UNBNDP (arg1)))
+ scm_wrong_num_args (proc);
+ if (scm_is_null (args))
+ args = SCM_UNDEFINED;
+ else
+ {
+ if (SCM_UNLIKELY (!scm_is_null (SCM_CDR (args))))
+ scm_wrong_num_args (proc);
+ args = SCM_CAR (args);
+ }
+ RETURN (SCM_SUBRF (proc) (arg1, args));
+ case scm_tc7_subr_2:
+ if (SCM_UNLIKELY (scm_is_null (args) || !scm_is_null (SCM_CDR (args))))
+ scm_wrong_num_args (proc);
+ args = SCM_CAR (args);
+ RETURN (SCM_SUBRF (proc) (arg1, args));
+ case scm_tc7_subr_0:
+ if (SCM_UNLIKELY (!SCM_UNBNDP (arg1)))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) ());
+ case scm_tc7_subr_1:
+ if (SCM_UNLIKELY (SCM_UNBNDP (arg1)))
+ scm_wrong_num_args (proc);
+ case scm_tc7_subr_1o:
+ if (SCM_UNLIKELY (!scm_is_null (args)))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) (arg1));
+ case scm_tc7_dsubr:
+ if (SCM_UNLIKELY (SCM_UNBNDP (arg1) || !scm_is_null (args)))
+ scm_wrong_num_args (proc);
+ 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)));
+ case scm_tc7_cxr:
+ if (SCM_UNLIKELY (SCM_UNBNDP (arg1) || !scm_is_null (args)))
+ scm_wrong_num_args (proc);
+ RETURN (scm_i_chase_pairs (arg1, (scm_t_bits) SCM_SUBRF (proc)));
+ case scm_tc7_subr_3:
+ if (SCM_UNLIKELY (scm_is_null (args)
+ || scm_is_null (SCM_CDR (args))
+ || !scm_is_null (SCM_CDDR (args))))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) (arg1, SCM_CAR (args), SCM_CADR (args)));
+ case scm_tc7_lsubr:
+#ifdef DEVAL
+ RETURN (SCM_SUBRF (proc) (SCM_UNBNDP (arg1) ? SCM_EOL : debug.vect[0].a.args));
+#else
+ RETURN (SCM_SUBRF (proc) (SCM_UNBNDP (arg1) ? SCM_EOL : scm_cons (arg1, args)));
+#endif
+ case scm_tc7_lsubr_2:
+ if (SCM_UNLIKELY (!scm_is_pair (args)))
+ scm_wrong_num_args (proc);
+ else
+ RETURN (SCM_SUBRF (proc) (arg1, SCM_CAR (args), SCM_CDR (args)));
+ case scm_tc7_asubr:
+ if (scm_is_null (args))
+ RETURN (SCM_SUBRF (proc) (arg1, SCM_UNDEFINED));
+ while (SCM_NIMP (args))
+ {
+ SCM_ASSERT (scm_is_pair (args), args, SCM_ARG2, "apply");
+ arg1 = SCM_SUBRF (proc) (arg1, SCM_CAR (args));
+ args = SCM_CDR (args);
+ }
+ RETURN (arg1);
+ case scm_tc7_rpsubr:
+ if (scm_is_null (args))
+ RETURN (SCM_BOOL_T);
+ while (SCM_NIMP (args))
+ {
+ SCM_ASSERT (scm_is_pair (args), args, SCM_ARG2, "apply");
+ if (scm_is_false (SCM_SUBRF (proc) (arg1, SCM_CAR (args))))
+ RETURN (SCM_BOOL_F);
+ arg1 = SCM_CAR (args);
+ args = SCM_CDR (args);
+ }
+ RETURN (SCM_BOOL_T);
+ case scm_tcs_closures:
+#ifdef DEVAL
+ arg1 = (SCM_UNBNDP (arg1) ? SCM_EOL : debug.vect[0].a.args);
+#else
+ arg1 = (SCM_UNBNDP (arg1) ? SCM_EOL : scm_cons (arg1, args));
+#endif
+ if (SCM_UNLIKELY (scm_badargsp (SCM_CLOSURE_FORMALS (proc), arg1)))
+ scm_wrong_num_args (proc);
+
+ /* Copy argument list */
+ if (SCM_IMP (arg1))
+ args = arg1;
+ else
+ {
+ SCM tl = args = scm_cons (SCM_CAR (arg1), SCM_UNSPECIFIED);
+ for (arg1 = SCM_CDR (arg1); scm_is_pair (arg1); arg1 = SCM_CDR (arg1))
+ {
+ SCM_SETCDR (tl, scm_cons (SCM_CAR (arg1), SCM_UNSPECIFIED));
+ tl = SCM_CDR (tl);
+ }
+ SCM_SETCDR (tl, arg1);
+ }
+
+ args = SCM_EXTEND_ENV (SCM_CLOSURE_FORMALS (proc),
+ args,
+ SCM_ENV (proc));
+ proc = SCM_CLOSURE_BODY (proc);
+ again:
+ arg1 = SCM_CDR (proc);
+ while (!scm_is_null (arg1))
+ {
+ if (SCM_IMP (SCM_CAR (proc)))
+ {
+ if (SCM_ISYMP (SCM_CAR (proc)))
+ {
+ scm_dynwind_begin (0);
+ scm_i_dynwind_pthread_mutex_lock (&source_mutex);
+ /* check for race condition */
+ if (SCM_ISYMP (SCM_CAR (proc)))
+ m_expand_body (proc, args);
+ scm_dynwind_end ();
+ goto again;
+ }
+ else
+ SCM_VALIDATE_NON_EMPTY_COMBINATION (SCM_CAR (proc));
+ }
+ else
+ (void) EVAL (SCM_CAR (proc), args);
+ proc = arg1;
+ arg1 = SCM_CDR (proc);
+ }
+ RETURN (EVALCAR (proc, args));
+ case scm_tc7_smob:
+ if (!SCM_SMOB_APPLICABLE_P (proc))
+ goto badproc;
+ if (SCM_UNBNDP (arg1))
+ RETURN (SCM_SMOB_APPLY_0 (proc));
+ else if (scm_is_null (args))
+ RETURN (SCM_SMOB_APPLY_1 (proc, arg1));
+ else if (scm_is_null (SCM_CDR (args)))
+ RETURN (SCM_SMOB_APPLY_2 (proc, arg1, SCM_CAR (args)));
+ else
+ RETURN (SCM_SMOB_APPLY_3 (proc, arg1, SCM_CAR (args), SCM_CDR (args)));
+ case scm_tc7_cclo:
+#ifdef DEVAL
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : debug.vect[0].a.args);
+ arg1 = proc;
+ proc = SCM_CCLO_SUBR (proc);
+ debug.vect[0].a.proc = proc;
+ debug.vect[0].a.args = scm_cons (arg1, args);
+#else
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : scm_cons (arg1, args));
+ arg1 = proc;
+ proc = SCM_CCLO_SUBR (proc);
+#endif
+ goto tail;
+ case scm_tc7_pws:
+ proc = SCM_PROCEDURE (proc);
+#ifdef DEVAL
+ debug.vect[0].a.proc = proc;
+#endif
+ goto tail;
+ case scm_tcs_struct:
+ if (SCM_OBJ_CLASS_FLAGS (proc) & SCM_CLASSF_PURE_GENERIC)
+ {
+#ifdef DEVAL
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : debug.vect[0].a.args);
+#else
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : scm_cons (arg1, args));
+#endif
+ RETURN (scm_apply_generic (proc, args));
+ }
+ else if (SCM_I_OPERATORP (proc))
+ {
+ /* operator */
+#ifdef DEVAL
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : debug.vect[0].a.args);
+#else
+ args = (SCM_UNBNDP(arg1) ? SCM_EOL : scm_cons (arg1, args));
+#endif
+ arg1 = proc;
+ proc = (SCM_I_ENTITYP (proc)
+ ? SCM_ENTITY_PROCEDURE (proc)
+ : SCM_OPERATOR_PROCEDURE (proc));
+#ifdef DEVAL
+ debug.vect[0].a.proc = proc;
+ debug.vect[0].a.args = scm_cons (arg1, args);
+#endif
+ if (SCM_NIMP (proc))
+ goto tail;
+ else
+ goto badproc;
+ }
+ else
+ goto badproc;
+ default:
+ badproc:
+ scm_wrong_type_arg ("apply", SCM_ARG1, proc);
+ }
+#ifdef DEVAL
+exit:
+ if (scm_check_exit_p && SCM_TRAPS_P)
+ if (SCM_EXIT_FRAME_P || (SCM_TRACE_P && SCM_TRACED_FRAME_P (debug)))
+ {
+ SCM_CLEAR_TRACED_FRAME (debug);
+ arg1 = scm_make_debugobj (&debug);
+ SCM_TRAPS_P = 0;
+ arg1 = scm_call_3 (SCM_EXIT_FRAME_HDLR, scm_sym_exit_frame, arg1, proc);
+ SCM_TRAPS_P = 1;
+ if (scm_is_pair (arg1) && scm_is_eq (SCM_CAR (arg1), sym_instead))
+ proc = SCM_CDR (arg1);
+ }
+ scm_i_set_last_debug_frame (debug.prev);
+ return proc;
+#endif
+}
+
+
+/* SECTION: The rest of this file is only read once.
+ */
+
+#ifndef DEVAL
+
+/* 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
+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
+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.c"
+
+
+#if (SCM_ENABLE_DEPRECATED == 1)
+
+/* Deprecated in guile 1.7.0 on 2004-03-29. */
+SCM scm_ceval (SCM x, SCM env)
+{
+ if (scm_is_pair (x))
+ return ceval (x, env);
+ else if (scm_is_symbol (x))
+ return *scm_lookupcar (scm_cons (x, SCM_UNDEFINED), env, 1);
+ else
+ return SCM_I_XEVAL (x, env);
+}
+
+/* Deprecated in guile 1.7.0 on 2004-03-29. */
+SCM scm_deval (SCM x, SCM env)
+{
+ if (scm_is_pair (x))
+ return deval (x, env);
+ else if (scm_is_symbol (x))
+ return *scm_lookupcar (scm_cons (x, SCM_UNDEFINED), env, 1);
+ else
+ return SCM_I_XEVAL (x, env);
+}
+
+static SCM
+dispatching_eval (SCM x, SCM env)
+{
+ if (scm_debug_mode_p)
+ return scm_deval (x, env);
+ else
+ return scm_ceval (x, env);
+}
+
+/* Deprecated in guile 1.7.0 on 2004-03-29. */
+SCM (*scm_ceval_ptr) (SCM x, SCM env) = dispatching_eval;
+
+#endif
+
+
+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_N_EVALUATOR_TRAPS);
+ scm_init_opts (scm_eval_options_interface,
+ scm_eval_opts,
+ SCM_N_EVAL_OPTIONS);
+
+ 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");
+}
+
+#endif /* !DEVAL */
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
projects / lilypond.git / blobdiff