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Diffstat (limited to 'libguile/expand.c')
-rw-r--r-- | libguile/expand.c | 1253 |
1 files changed, 1253 insertions, 0 deletions
diff --git a/libguile/expand.c b/libguile/expand.c new file mode 100644 index 000000000..e122496c8 --- /dev/null +++ b/libguile/expand.c @@ -0,0 +1,1253 @@ +/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010 + * Free Software Foundation, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 3 of + * the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301 USA + */ + + + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include "libguile/__scm.h" +#include "libguile/_scm.h" +#include "libguile/continuations.h" +#include "libguile/eq.h" +#include "libguile/list.h" +#include "libguile/macros.h" +#include "libguile/expand.h" +#include "libguile/modules.h" +#include "libguile/srcprop.h" +#include "libguile/ports.h" +#include "libguile/print.h" +#include "libguile/strings.h" +#include "libguile/throw.h" +#include "libguile/validate.h" + + + + + +SCM scm_exp_vtable_vtable; +static SCM exp_vtables[SCM_NUM_EXPANDED_TYPES]; +static size_t exp_nfields[SCM_NUM_EXPANDED_TYPES]; +static const char* exp_names[SCM_NUM_EXPANDED_TYPES]; +static const char** exp_field_names[SCM_NUM_EXPANDED_TYPES]; + + +#define VOID(src) \ + SCM_MAKE_EXPANDED_VOID(src) +#define CONST(src, exp) \ + SCM_MAKE_EXPANDED_CONST(src, exp) +#define PRIMITIVE_REF_TYPE(src, name) \ + SCM_MAKE_EXPANDED_PRIMITIVE_REF_TYPE(src, name) +#define LEXICAL_REF(src, name, gensym) \ + SCM_MAKE_EXPANDED_LEXICAL_REF(src, name, gensym) +#define LEXICAL_SET(src, name, gensym, exp) \ + SCM_MAKE_EXPANDED_LEXICAL_SET(src, name, gensym, exp) +#define MODULE_REF(src, mod, name, public) \ + SCM_MAKE_EXPANDED_MODULE_REF(src, mod, name, public) +#define MODULE_SET(src, mod, name, public, exp) \ + SCM_MAKE_EXPANDED_MODULE_SET(src, mod, name, public, exp) +#define TOPLEVEL_REF(src, name) \ + SCM_MAKE_EXPANDED_TOPLEVEL_REF(src, name) +#define TOPLEVEL_SET(src, name, exp) \ + SCM_MAKE_EXPANDED_TOPLEVEL_SET(src, name, exp) +#define TOPLEVEL_DEFINE(src, name, exp) \ + SCM_MAKE_EXPANDED_TOPLEVEL_DEFINE(src, name, exp) +#define CONDITIONAL(src, test, consequent, alternate) \ + SCM_MAKE_EXPANDED_CONDITIONAL(src, test, consequent, alternate) +#define APPLICATION(src, proc, exps) \ + SCM_MAKE_EXPANDED_APPLICATION(src, proc, exps) +#define SEQUENCE(src, exps) \ + SCM_MAKE_EXPANDED_SEQUENCE(src, exps) +#define LAMBDA(src, meta, body) \ + SCM_MAKE_EXPANDED_LAMBDA(src, meta, body) +#define LAMBDA_CASE(src, req, opt, rest, kw, inits, gensyms, body, alternate) \ + SCM_MAKE_EXPANDED_LAMBDA_CASE(src, req, opt, rest, kw, inits, gensyms, body, alternate) +#define LET(src, names, gensyms, vals, body) \ + SCM_MAKE_EXPANDED_LET(src, names, gensyms, vals, body) +#define LETREC(src, names, gensyms, vals, body) \ + SCM_MAKE_EXPANDED_LETREC(src, names, gensyms, vals, body) +#define DYNLET(src, fluids, vals, body) \ + SCM_MAKE_EXPANDED_DYNLET(src, fluids, vals, body) + +#define CAR(x) SCM_CAR(x) +#define CDR(x) SCM_CDR(x) +#define CAAR(x) SCM_CAAR(x) +#define CADR(x) SCM_CADR(x) +#define CDAR(x) SCM_CDAR(x) +#define CDDR(x) SCM_CDDR(x) +#define CADDR(x) SCM_CADDR(x) +#define CDDDR(x) SCM_CDDDR(x) +#define CADDDR(x) SCM_CADDDR(x) + + +static const char s_bad_expression[] = "Bad expression"; +static const char s_expression[] = "Missing or extra expression in"; +static const char s_missing_expression[] = "Missing expression in"; +static const char s_extra_expression[] = "Extra expression in"; +static const char s_empty_combination[] = "Illegal empty combination"; +static const char s_missing_body_expression[] = "Missing body expression in"; +static const char s_mixed_body_forms[] = "Mixed definitions and expressions in"; +static const char s_bad_define[] = "Bad define placement"; +static const char s_missing_clauses[] = "Missing clauses"; +static const char s_misplaced_else_clause[] = "Misplaced else clause"; +static const char s_bad_case_clause[] = "Bad case clause"; +static const char s_bad_case_labels[] = "Bad case labels"; +static const char s_duplicate_case_label[] = "Duplicate case label"; +static const char s_bad_cond_clause[] = "Bad cond clause"; +static const char s_missing_recipient[] = "Missing recipient in"; +static const char s_bad_variable[] = "Bad variable"; +static const char s_bad_bindings[] = "Bad bindings"; +static const char s_bad_binding[] = "Bad binding"; +static const char s_duplicate_binding[] = "Duplicate binding"; +static const char s_bad_exit_clause[] = "Bad exit clause"; +static const char s_bad_formals[] = "Bad formals"; +static const char s_bad_formal[] = "Bad formal"; +static const char s_duplicate_formal[] = "Duplicate formal"; +static const char s_splicing[] = "Non-list result for unquote-splicing"; +static const char s_bad_slot_number[] = "Bad slot number"; + +static void syntax_error (const char* const, const SCM, const SCM) SCM_NORETURN; + +SCM_SYMBOL (syntax_error_key, "syntax-error"); + +/* 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); } + + + + +/* Primitive syntax. */ + +#define SCM_SYNTAX(STR, CFN) \ +SCM_SNARF_HERE(static SCM CFN (SCM xorig, SCM env)) \ +SCM_SNARF_INIT(scm_c_define (STR, scm_i_make_primitive_macro (STR, CFN))) + + +/* True primitive syntax */ +SCM_SYNTAX ("@", expand_at); +SCM_SYNTAX ("@@", expand_atat); +SCM_SYNTAX ("begin", expand_begin); +SCM_SYNTAX ("define", expand_define); +SCM_SYNTAX ("with-fluids", expand_with_fluids); +SCM_SYNTAX ("eval-when", expand_eval_when); +SCM_SYNTAX ("if", expand_if); +SCM_SYNTAX ("lambda", expand_lambda); +SCM_SYNTAX ("let", expand_let); +SCM_SYNTAX ("quote", expand_quote); +SCM_SYNTAX ("set!", expand_set_x); + +/* Convenient syntax during boot, expands to primitive syntax. Replaced after + psyntax boots. */ +SCM_SYNTAX ("and", expand_and); +SCM_SYNTAX ("cond", expand_cond); +SCM_SYNTAX ("letrec", expand_letrec); +SCM_SYNTAX ("let*", expand_letstar); +SCM_SYNTAX ("or", expand_or); +SCM_SYNTAX ("lambda*", expand_lambda_star); +SCM_SYNTAX ("case-lambda", expand_case_lambda); +SCM_SYNTAX ("case-lambda*", expand_case_lambda_star); + + +SCM_GLOBAL_SYMBOL (scm_sym_apply, "apply"); +SCM_GLOBAL_SYMBOL (scm_sym_arrow, "=>"); +SCM_GLOBAL_SYMBOL (scm_sym_at, "@"); +SCM_GLOBAL_SYMBOL (scm_sym_atat, "@@"); +SCM_GLOBAL_SYMBOL (scm_sym_at_call_with_values, "@call-with-values"); +SCM_GLOBAL_SYMBOL (scm_sym_atapply, "@apply"); +SCM_GLOBAL_SYMBOL (scm_sym_atcall_cc, "@call-with-current-continuation"); +SCM_GLOBAL_SYMBOL (scm_sym_begin, "begin"); +SCM_GLOBAL_SYMBOL (scm_sym_case, "case"); +SCM_GLOBAL_SYMBOL (scm_sym_cond, "cond"); +SCM_GLOBAL_SYMBOL (scm_sym_define, "define"); +SCM_GLOBAL_SYMBOL (scm_sym_at_dynamic_wind, "@dynamic-wind"); +SCM_GLOBAL_SYMBOL (scm_sym_with_fluids, "with-fluids"); +SCM_GLOBAL_SYMBOL (scm_sym_else, "else"); +SCM_GLOBAL_SYMBOL (scm_sym_eval_when, "eval-when"); +SCM_GLOBAL_SYMBOL (scm_sym_if, "if"); +SCM_GLOBAL_SYMBOL (scm_sym_lambda, "lambda"); +SCM_GLOBAL_SYMBOL (scm_sym_let, "let"); +SCM_GLOBAL_SYMBOL (scm_sym_letrec, "letrec"); +SCM_GLOBAL_SYMBOL (scm_sym_letstar, "let*"); +SCM_GLOBAL_SYMBOL (scm_sym_or, "or"); +SCM_GLOBAL_SYMBOL (scm_sym_at_prompt, "@prompt"); +SCM_GLOBAL_SYMBOL (scm_sym_quote, "quote"); +SCM_GLOBAL_SYMBOL (scm_sym_set_x, "set!"); +SCM_SYMBOL (sym_lambda_star, "lambda*"); +SCM_SYMBOL (sym_eval, "eval"); +SCM_SYMBOL (sym_load, "load"); + +SCM_GLOBAL_SYMBOL (scm_sym_unquote, "unquote"); +SCM_GLOBAL_SYMBOL (scm_sym_quasiquote, "quasiquote"); +SCM_GLOBAL_SYMBOL (scm_sym_uq_splicing, "unquote-splicing"); + +SCM_KEYWORD (kw_allow_other_keys, "allow-other-keys"); +SCM_KEYWORD (kw_optional, "optional"); +SCM_KEYWORD (kw_key, "key"); +SCM_KEYWORD (kw_rest, "rest"); + + + + + +/* 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>. */ + +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); +} + + + + + +static int +expand_env_var_is_free (SCM env, SCM x) +{ + for (; scm_is_pair (env); env = CDR (env)) + if (scm_is_eq (x, CAAR (env))) + return 0; /* bound */ + return 1; /* free */ +} + +static SCM +expand_env_ref_macro (SCM env, SCM x) +{ + SCM var; + if (!expand_env_var_is_free (env, x)) + return SCM_BOOL_F; /* lexical */ + + var = scm_module_variable (scm_current_module (), x); + if (scm_is_true (var) && scm_is_true (scm_variable_bound_p (var)) + && scm_is_true (scm_macro_p (scm_variable_ref (var)))) + return scm_variable_ref (var); + else + return SCM_BOOL_F; /* anything else */ +} + +static SCM +expand_env_lexical_gensym (SCM env, SCM name) +{ + for (; scm_is_pair (env); env = CDR (env)) + if (scm_is_eq (name, CAAR (env))) + return CDAR (env); /* bound */ + return SCM_BOOL_F; /* free */ +} + +static SCM +expand_env_extend (SCM env, SCM names, SCM vars) +{ + while (scm_is_pair (names)) + { + env = scm_acons (CAR (names), CAR (vars), env); + names = CDR (names); + vars = CDR (vars); + } + return env; +} + +static SCM +expand (SCM exp, SCM env) +{ + if (scm_is_pair (exp)) + { + SCM car; + scm_t_macro_primitive trans = NULL; + SCM macro = SCM_BOOL_F; + + car = CAR (exp); + if (scm_is_symbol (car)) + macro = expand_env_ref_macro (env, car); + + if (scm_is_true (macro)) + trans = scm_i_macro_primitive (macro); + + if (trans) + return trans (exp, env); + else + { + SCM arg_exps = SCM_EOL; + SCM args = SCM_EOL; + SCM proc = CAR (exp); + + for (arg_exps = CDR (exp); scm_is_pair (arg_exps); + arg_exps = CDR (arg_exps)) + args = scm_cons (expand (CAR (arg_exps), env), args); + if (scm_is_null (arg_exps)) + return APPLICATION (scm_source_properties (exp), + expand (proc, env), + scm_reverse_x (args, SCM_UNDEFINED)); + else + syntax_error ("expected a proper list", exp, SCM_UNDEFINED); + } + } + else if (scm_is_symbol (exp)) + { + SCM gensym = expand_env_lexical_gensym (env, exp); + if (scm_is_true (gensym)) + return LEXICAL_REF (SCM_BOOL_F, exp, gensym); + else + return TOPLEVEL_REF (SCM_BOOL_F, exp); + } + else + return CONST (SCM_BOOL_F, exp); +} + +static SCM +expand_exprs (SCM forms, const SCM env) +{ + SCM ret = SCM_EOL; + + for (; !scm_is_null (forms); forms = CDR (forms)) + ret = scm_cons (expand (CAR (forms), env), ret); + return scm_reverse_x (ret, SCM_UNDEFINED); +} + +static SCM +expand_sequence (const SCM forms, const SCM env) +{ + ASSERT_SYNTAX (scm_ilength (forms) >= 1, s_bad_expression, + scm_cons (scm_sym_begin, forms)); + if (scm_is_null (CDR (forms))) + return expand (CAR (forms), env); + else + return SEQUENCE (SCM_BOOL_F, expand_exprs (forms, env)); +} + + + + + +static SCM +expand_at (SCM expr, SCM env SCM_UNUSED) +{ + ASSERT_SYNTAX (scm_ilength (expr) == 3, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (CADR (expr)) > 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_is_symbol (CADDR (expr)), s_bad_expression, expr); + + return MODULE_REF (scm_source_properties (expr), + CADR (expr), CADDR (expr), SCM_BOOL_T); +} + +static SCM +expand_atat (SCM expr, SCM env SCM_UNUSED) +{ + ASSERT_SYNTAX (scm_ilength (expr) == 3, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (CADR (expr)) > 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_is_symbol (CADDR (expr)), s_bad_expression, expr); + + return MODULE_REF (scm_source_properties (expr), + CADR (expr), CADDR (expr), SCM_BOOL_F); +} + +static SCM +expand_and (SCM expr, SCM env) +{ + const SCM cdr_expr = CDR (expr); + + if (scm_is_null (cdr_expr)) + return CONST (SCM_BOOL_F, SCM_BOOL_T); + + ASSERT_SYNTAX (scm_is_pair (cdr_expr), s_bad_expression, expr); + + if (scm_is_null (CDR (cdr_expr))) + return expand (CAR (cdr_expr), env); + else + return CONDITIONAL (scm_source_properties (expr), + expand (CAR (cdr_expr), env), + expand_and (cdr_expr, env), + CONST (SCM_BOOL_F, SCM_BOOL_F)); +} + +static SCM +expand_begin (SCM expr, SCM env) +{ + const SCM cdr_expr = CDR (expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 1, s_bad_expression, expr); + return expand_sequence (cdr_expr, env); +} + +static SCM +expand_cond_clauses (SCM clause, SCM rest, int elp, int alp, SCM env) +{ + SCM test; + const long length = scm_ilength (clause); + ASSERT_SYNTAX (length >= 1, s_bad_cond_clause, clause); + + test = CAR (clause); + if (scm_is_eq (test, scm_sym_else) && elp) + { + const int last_clause_p = scm_is_null (rest); + ASSERT_SYNTAX (length >= 2, s_bad_cond_clause, clause); + ASSERT_SYNTAX (last_clause_p, s_misplaced_else_clause, clause); + return expand_sequence (CDR (clause), env); + } + + if (scm_is_null (rest)) + rest = VOID (SCM_BOOL_F); + else + rest = expand_cond_clauses (CAR (rest), CDR (rest), elp, alp, env); + + if (length >= 2 + && scm_is_eq (CADR (clause), scm_sym_arrow) + && alp) + { + SCM tmp = scm_gensym (scm_from_locale_string ("cond ")); + SCM new_env = scm_acons (tmp, tmp, env); + ASSERT_SYNTAX (length > 2, s_missing_recipient, clause); + ASSERT_SYNTAX (length == 3, s_extra_expression, clause); + return LET (SCM_BOOL_F, + scm_list_1 (tmp), + scm_list_1 (tmp), + scm_list_1 (expand (test, env)), + CONDITIONAL (SCM_BOOL_F, + LEXICAL_REF (SCM_BOOL_F, tmp, tmp), + APPLICATION (SCM_BOOL_F, + expand (CADDR (clause), new_env), + scm_list_1 (LEXICAL_REF (SCM_BOOL_F, + tmp, tmp))), + rest)); + } + /* FIXME length == 1 case */ + else + return CONDITIONAL (SCM_BOOL_F, + expand (test, env), + expand_sequence (CDR (clause), env), + rest); +} + +static SCM +expand_cond (SCM expr, SCM env) +{ + const int else_literal_p = expand_env_var_is_free (env, scm_sym_else); + const int arrow_literal_p = expand_env_var_is_free (env, scm_sym_arrow); + const SCM clauses = CDR (expr); + + ASSERT_SYNTAX (scm_ilength (clauses) >= 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (clauses) >= 1, s_missing_clauses, expr); + + return expand_cond_clauses (CAR (clauses), CDR (clauses), + else_literal_p, arrow_literal_p, env); +} + +/* lone forward decl */ +static SCM expand_lambda (SCM expr, SCM env); + +/* 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)))'. */ +static SCM +expand_define (SCM expr, SCM env) +{ + const SCM cdr_expr = CDR (expr); + SCM body; + SCM variable; + + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr); + ASSERT_SYNTAX (!scm_is_pair (env), s_bad_define, expr); + + body = CDR (cdr_expr); + variable = CAR (cdr_expr); + + if (scm_is_pair (variable)) + { + ASSERT_SYNTAX_2 (scm_is_symbol (CAR (variable)), s_bad_variable, variable, expr); + return TOPLEVEL_DEFINE + (scm_source_properties (expr), + CAR (variable), + expand_lambda (scm_cons (scm_sym_lambda, scm_cons (CDR (variable), body)), + env)); + } + ASSERT_SYNTAX_2 (scm_is_symbol (variable), s_bad_variable, variable, expr); + ASSERT_SYNTAX (scm_ilength (body) == 1, s_expression, expr); + return TOPLEVEL_DEFINE (scm_source_properties (expr), variable, + expand (CAR (body), env)); +} + +static SCM +expand_with_fluids (SCM expr, SCM env) +{ + SCM binds, fluids, vals; + ASSERT_SYNTAX (scm_ilength (expr) >= 3, s_bad_expression, expr); + binds = CADR (expr); + ASSERT_SYNTAX_2 (scm_ilength (binds) >= 0, s_bad_bindings, binds, expr); + for (fluids = SCM_EOL, vals = SCM_EOL; + scm_is_pair (binds); + binds = CDR (binds)) + { + SCM binding = CAR (binds); + ASSERT_SYNTAX_2 (scm_ilength (CAR (binds)) == 2, s_bad_binding, + binding, expr); + fluids = scm_cons (expand (CAR (binding), env), fluids); + vals = scm_cons (expand (CADR (binding), env), vals); + } + + return DYNLET (scm_source_properties (expr), + scm_reverse_x (fluids, SCM_UNDEFINED), + scm_reverse_x (vals, SCM_UNDEFINED), + expand_sequence (CDDR (expr), env)); +} + +static SCM +expand_eval_when (SCM expr, SCM env) +{ + ASSERT_SYNTAX (scm_ilength (expr) >= 3, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (CADR (expr)) > 0, s_bad_expression, expr); + + if (scm_is_true (scm_memq (sym_eval, CADR (expr))) + || scm_is_true (scm_memq (sym_load, CADR (expr)))) + return expand_sequence (CDDR (expr), env); + else + return VOID (scm_source_properties (expr)); +} + +static SCM +expand_if (SCM expr, SCM env SCM_UNUSED) +{ + const SCM cdr_expr = CDR (expr); + const long length = scm_ilength (cdr_expr); + ASSERT_SYNTAX (length == 2 || length == 3, s_expression, expr); + return CONDITIONAL (scm_source_properties (expr), + expand (CADR (expr), env), + expand (CADDR (expr), env), + ((length == 3) + ? expand (CADDDR (expr), env) + : VOID (SCM_BOOL_F))); +} + +/* A helper function for expand_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 = CDR (list)) + { + if (scm_is_eq (CAR (list), obj)) + return 1; + } + return scm_is_eq (list, obj); +} + +static SCM +expand_lambda_case (SCM clause, SCM alternate, SCM env) +{ + SCM formals; + SCM rest; + SCM req = SCM_EOL; + SCM vars = SCM_EOL; + SCM body; + int nreq = 0; + + ASSERT_SYNTAX (scm_is_pair (clause) && scm_is_pair (CDR (clause)), + s_bad_expression, scm_cons (scm_sym_lambda, clause)); + + /* Before iterating the list of formal arguments, make sure the formals + * actually are given as either a symbol or a non-cyclic list. */ + formals = CAR (clause); + 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, scm_cons (scm_sym_lambda, clause)); + + /* Now iterate the list of formal arguments to check if all formals are + * symbols, and that there are no duplicates. */ + while (scm_is_pair (formals)) + { + const SCM formal = CAR (formals); + formals = CDR (formals); + ASSERT_SYNTAX_2 (scm_is_symbol (formal), s_bad_formal, formal, + scm_cons (scm_sym_lambda, clause)); + ASSERT_SYNTAX_2 (!c_improper_memq (formal, formals), s_duplicate_formal, + formal, scm_cons (scm_sym_lambda, clause)); + nreq++; + req = scm_cons (formal, req); + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (formal, CAR (vars), env); + } + + ASSERT_SYNTAX_2 (scm_is_null (formals) || scm_is_symbol (formals), + s_bad_formal, formals, scm_cons (scm_sym_lambda, clause)); + if (scm_is_symbol (formals)) + { + rest = formals; + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (rest, CAR (vars), env); + } + else + rest = SCM_BOOL_F; + + body = expand_sequence (CDR (clause), env); + req = scm_reverse_x (req, SCM_UNDEFINED); + vars = scm_reverse_x (vars, SCM_UNDEFINED); + + if (scm_is_true (alternate) && !(SCM_EXPANDED_P (alternate) && SCM_EXPANDED_TYPE (alternate) == SCM_EXPANDED_LAMBDA_CASE)) + abort (); + + return LAMBDA_CASE (SCM_BOOL_F, req, SCM_BOOL_F, rest, SCM_BOOL_F, + SCM_EOL, vars, body, alternate); +} + +static SCM +expand_lambda (SCM expr, SCM env) +{ + return LAMBDA (scm_source_properties (expr), + SCM_EOL, + expand_lambda_case (CDR (expr), SCM_BOOL_F, env)); +} + +static SCM +expand_lambda_star_case (SCM clause, SCM alternate, SCM env) +{ + SCM req, opt, kw, allow_other_keys, rest, formals, vars, body, tmp; + SCM inits, kw_indices; + int nreq, nopt; + + const long length = scm_ilength (clause); + ASSERT_SYNTAX (length >= 1, s_bad_expression, + scm_cons (sym_lambda_star, clause)); + ASSERT_SYNTAX (length >= 2, s_missing_expression, + scm_cons (sym_lambda_star, clause)); + + formals = CAR (clause); + body = CDR (clause); + + nreq = nopt = 0; + req = opt = kw = SCM_EOL; + rest = allow_other_keys = SCM_BOOL_F; + + while (scm_is_pair (formals) && scm_is_symbol (CAR (formals))) + { + nreq++; + req = scm_cons (CAR (formals), req); + formals = scm_cdr (formals); + } + + if (scm_is_pair (formals) && scm_is_eq (CAR (formals), kw_optional)) + { + formals = CDR (formals); + while (scm_is_pair (formals) + && (scm_is_symbol (CAR (formals)) || scm_is_pair (CAR (formals)))) + { + nopt++; + opt = scm_cons (CAR (formals), opt); + formals = scm_cdr (formals); + } + } + + if (scm_is_pair (formals) && scm_is_eq (CAR (formals), kw_key)) + { + formals = CDR (formals); + while (scm_is_pair (formals) + && (scm_is_symbol (CAR (formals)) || scm_is_pair (CAR (formals)))) + { + kw = scm_cons (CAR (formals), kw); + formals = scm_cdr (formals); + } + } + + if (scm_is_pair (formals) && scm_is_eq (CAR (formals), kw_allow_other_keys)) + { + formals = CDR (formals); + allow_other_keys = SCM_BOOL_T; + } + + if (scm_is_pair (formals) && scm_is_eq (CAR (formals), kw_rest)) + { + ASSERT_SYNTAX (scm_ilength (formals) == 2, s_bad_formals, + CAR (clause)); + rest = CADR (formals); + } + else if (scm_is_symbol (formals)) + rest = formals; + else + { + ASSERT_SYNTAX (scm_is_null (formals), s_bad_formals, CAR (clause)); + rest = SCM_BOOL_F; + } + + /* Now, iterate through them a second time, building up an expansion-time + environment, checking, expanding and canonicalizing the opt/kw init forms, + and eventually memoizing the body as well. Note that the rest argument, if + any, is expanded before keyword args, thus necessitating the second + pass. + + Also note that the specific environment during expansion of init + expressions here needs to coincide with the environment when psyntax + expands. A lot of effort for something that is only used in the bootstrap + expandr, you say? Yes. Yes it is. + */ + + vars = SCM_EOL; + req = scm_reverse_x (req, SCM_EOL); + for (tmp = req; scm_is_pair (tmp); tmp = scm_cdr (tmp)) + { + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (CAR (tmp), CAR (vars), env); + } + + /* Build up opt inits and env */ + inits = SCM_EOL; + opt = scm_reverse_x (opt, SCM_EOL); + for (tmp = opt; scm_is_pair (tmp); tmp = scm_cdr (tmp)) + { + SCM x = CAR (tmp); + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (x, CAR (vars), env); + if (scm_is_symbol (x)) + inits = scm_cons (CONST (SCM_BOOL_F, SCM_BOOL_F), inits); + else + { + ASSERT_SYNTAX (scm_ilength (x) == 2 && scm_is_symbol (CAR (x)), + s_bad_formals, CAR (clause)); + inits = scm_cons (expand (CADR (x), env), inits); + } + env = scm_acons (scm_is_symbol (x) ? x : CAR (x), CAR (vars), env); + } + if (scm_is_null (opt)) + opt = SCM_BOOL_F; + + /* Process rest before keyword args */ + if (scm_is_true (rest)) + { + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (rest, CAR (vars), env); + } + + /* Build up kw inits, env, and kw-indices alist */ + if (scm_is_null (kw)) + kw = SCM_BOOL_F; + else + { + int idx = nreq + nopt + (scm_is_true (rest) ? 1 : 0); + + kw_indices = SCM_EOL; + kw = scm_reverse_x (kw, SCM_UNDEFINED); + for (tmp = kw; scm_is_pair (tmp); tmp = scm_cdr (tmp)) + { + SCM x, sym, k, init; + x = CAR (tmp); + if (scm_is_symbol (x)) + { + sym = x; + init = SCM_BOOL_F; + k = scm_symbol_to_keyword (sym); + } + else if (scm_ilength (x) == 2 && scm_is_symbol (CAR (x))) + { + sym = CAR (x); + init = CADR (x); + k = scm_symbol_to_keyword (sym); + } + else if (scm_ilength (x) == 3 && scm_is_symbol (CAR (x)) + && scm_is_keyword (CADDR (x))) + { + sym = CAR (x); + init = CADR (x); + k = CADDR (x); + } + else + syntax_error (s_bad_formals, CAR (clause), SCM_UNDEFINED); + + kw_indices = scm_acons (k, SCM_I_MAKINUM (idx++), kw_indices); + inits = scm_cons (expand (init, env), inits); + vars = scm_cons (scm_gensym (SCM_UNDEFINED), vars); + env = scm_acons (sym, CAR (vars), env); + } + kw_indices = scm_reverse_x (kw_indices, SCM_UNDEFINED); + kw = scm_cons (allow_other_keys, kw_indices); + } + + /* We should check for no duplicates, but given that psyntax does this + already, we can punt on it here... */ + + vars = scm_reverse_x (vars, SCM_UNDEFINED); + inits = scm_reverse_x (inits, SCM_UNDEFINED); + body = expand_sequence (body, env); + + return LAMBDA_CASE (SCM_BOOL_F, req, opt, rest, kw, inits, vars, body, + alternate); +} + +static SCM +expand_lambda_star (SCM expr, SCM env) +{ + return LAMBDA (scm_source_properties (expr), + SCM_EOL, + expand_lambda_star_case (CDR (expr), SCM_BOOL_F, env)); +} + +static SCM +expand_case_lambda_clauses (SCM expr, SCM rest, SCM env) +{ + SCM alt; + + if (scm_is_pair (rest)) + alt = expand_case_lambda_clauses (CAR (rest), CDR (rest), env); + else + alt = SCM_BOOL_F; + + return expand_lambda_case (expr, alt, env); +} + +static SCM +expand_case_lambda (SCM expr, SCM env) +{ + ASSERT_SYNTAX (scm_is_pair (CDR (expr)), s_missing_expression, expr); + + return LAMBDA (scm_source_properties (expr), + SCM_EOL, + expand_case_lambda_clauses (CADR (expr), CDDR (expr), env)); +} + +static SCM +expand_case_lambda_star_clauses (SCM expr, SCM rest, SCM env) +{ + SCM alt; + + if (scm_is_pair (rest)) + alt = expand_case_lambda_star_clauses (CAR (rest), CDR (rest), env); + else + alt = SCM_BOOL_F; + + return expand_lambda_star_case (expr, alt, env); +} + +static SCM +expand_case_lambda_star (SCM expr, SCM env) +{ + ASSERT_SYNTAX (scm_is_pair (CDR (expr)), s_missing_expression, expr); + + return LAMBDA (scm_source_properties (expr), + SCM_EOL, + expand_case_lambda_star_clauses (CADR (expr), CDDR (expr), env)); +} + +/* 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 = CDR (binding_idx)) + { + SCM name; /* const */ + + const SCM binding = CAR (binding_idx); + ASSERT_SYNTAX_2 (scm_ilength (binding) == 2, + s_bad_binding, binding, expr); + + name = 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). If a duplicate + * variable name is detected, an error is signalled. */ +static void +transform_bindings (const SCM bindings, const SCM expr, + SCM *const names, SCM *const vars, SCM *const initptr) +{ + SCM rnames = SCM_EOL; + SCM rvars = SCM_EOL; + SCM rinits = SCM_EOL; + SCM binding_idx = bindings; + for (; !scm_is_null (binding_idx); binding_idx = CDR (binding_idx)) + { + const SCM binding = CAR (binding_idx); + const SCM CDR_binding = CDR (binding); + const SCM name = CAR (binding); + ASSERT_SYNTAX_2 (scm_is_false (scm_c_memq (name, rnames)), + s_duplicate_binding, name, expr); + rnames = scm_cons (name, rnames); + rvars = scm_cons (scm_gensym (SCM_UNDEFINED), rvars); + rinits = scm_cons (CAR (CDR_binding), rinits); + } + *names = scm_reverse_x (rnames, SCM_UNDEFINED); + *vars = scm_reverse_x (rvars, SCM_UNDEFINED); + *initptr = scm_reverse_x (rinits, SCM_UNDEFINED); +} + +/* FIXME: Remove named let in this boot expander. */ +static SCM +expand_named_let (const SCM expr, SCM env) +{ + SCM var_names, var_syms, inits; + SCM inner_env; + SCM name_sym; + + const SCM cdr_expr = CDR (expr); + const SCM name = CAR (cdr_expr); + const SCM cddr_expr = CDR (cdr_expr); + const SCM bindings = CAR (cddr_expr); + check_bindings (bindings, expr); + + transform_bindings (bindings, expr, &var_names, &var_syms, &inits); + name_sym = scm_gensym (SCM_UNDEFINED); + inner_env = scm_acons (name, name_sym, env); + inner_env = expand_env_extend (inner_env, var_names, var_syms); + + return LETREC + (scm_source_properties (expr), + scm_list_1 (name), scm_list_1 (name_sym), + scm_list_1 (LAMBDA (SCM_BOOL_F, + SCM_EOL, + LAMBDA_CASE (SCM_BOOL_F, var_names, SCM_BOOL_F, SCM_BOOL_F, + SCM_BOOL_F, SCM_BOOL_F, var_syms, + expand_sequence (CDDDR (expr), inner_env), + SCM_BOOL_F))), + APPLICATION (SCM_BOOL_F, + LEXICAL_REF (SCM_BOOL_F, name, name_sym), + expand_exprs (inits, env))); +} + +static SCM +expand_let (SCM expr, SCM env) +{ + SCM bindings; + + const SCM cdr_expr = 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 = CAR (cdr_expr); + if (scm_is_symbol (bindings)) + { + ASSERT_SYNTAX (length >= 3, s_missing_expression, expr); + return expand_named_let (expr, env); + } + + check_bindings (bindings, expr); + if (scm_is_null (bindings)) + return expand_sequence (CDDR (expr), env); + else + { + SCM var_names, var_syms, inits; + transform_bindings (bindings, expr, &var_names, &var_syms, &inits); + return LET (SCM_BOOL_F, + var_names, var_syms, expand_exprs (inits, env), + expand_sequence (CDDR (expr), + expand_env_extend (env, var_names, + var_syms))); + } +} + +static SCM +expand_letrec (SCM expr, SCM env) +{ + SCM bindings; + + const SCM cdr_expr = 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 = CAR (cdr_expr); + check_bindings (bindings, expr); + if (scm_is_null (bindings)) + return expand_sequence (CDDR (expr), env); + else + { + SCM var_names, var_syms, inits; + transform_bindings (bindings, expr, &var_names, &var_syms, &inits); + env = expand_env_extend (env, var_names, var_syms); + return LETREC (SCM_BOOL_F, + var_names, var_syms, expand_exprs (inits, env), + expand_sequence (CDDR (expr), env)); + } +} + +static SCM +expand_letstar_clause (SCM bindings, SCM body, SCM env SCM_UNUSED) +{ + if (scm_is_null (bindings)) + return expand_sequence (body, env); + else + { + SCM bind, name, sym, init; + + ASSERT_SYNTAX (scm_is_pair (bindings), s_bad_expression, bindings); + bind = CAR (bindings); + ASSERT_SYNTAX (scm_ilength (bind) == 2, s_bad_binding, bind); + name = CAR (bind); + sym = scm_gensym (SCM_UNDEFINED); + init = CADR (bind); + + return LET (SCM_BOOL_F, scm_list_1 (name), scm_list_1 (sym), + scm_list_1 (expand (init, env)), + expand_letstar_clause (CDR (bindings), body, + scm_acons (name, sym, env))); + } +} + +static SCM +expand_letstar (SCM expr, SCM env SCM_UNUSED) +{ + const SCM cdr_expr = CDR (expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 2, s_missing_expression, expr); + + return expand_letstar_clause (CADR (expr), CDDR (expr), env); +} + +static SCM +expand_or (SCM expr, SCM env SCM_UNUSED) +{ + SCM tail = CDR (expr); + const long length = scm_ilength (tail); + + ASSERT_SYNTAX (length >= 0, s_bad_expression, expr); + + if (scm_is_null (CDR (expr))) + return CONST (SCM_BOOL_F, SCM_BOOL_F); + else + { + SCM tmp = scm_gensym (SCM_UNDEFINED); + return LET (SCM_BOOL_F, + scm_list_1 (tmp), scm_list_1 (tmp), + scm_list_1 (expand (CADR (expr), env)), + CONDITIONAL (SCM_BOOL_F, + LEXICAL_REF (SCM_BOOL_F, tmp, tmp), + LEXICAL_REF (SCM_BOOL_F, tmp, tmp), + expand_or (CDR (expr), + scm_acons (tmp, tmp, env)))); + } +} + +static SCM +expand_quote (SCM expr, SCM env SCM_UNUSED) +{ + SCM quotee; + + const SCM cdr_expr = CDR (expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) == 1, s_expression, expr); + quotee = CAR (cdr_expr); + return CONST (scm_source_properties (expr), quotee); +} + +static SCM +expand_set_x (SCM expr, SCM env) +{ + SCM variable; + SCM vmem; + + const SCM cdr_expr = CDR (expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) >= 0, s_bad_expression, expr); + ASSERT_SYNTAX (scm_ilength (cdr_expr) == 2, s_expression, expr); + variable = CAR (cdr_expr); + vmem = expand (variable, env); + + switch (SCM_EXPANDED_TYPE (vmem)) + { + case SCM_EXPANDED_LEXICAL_REF: + return LEXICAL_SET (scm_source_properties (expr), + SCM_EXPANDED_REF (vmem, LEXICAL_REF, NAME), + SCM_EXPANDED_REF (vmem, LEXICAL_REF, GENSYM), + expand (CADDR (expr), env)); + case SCM_EXPANDED_TOPLEVEL_REF: + return TOPLEVEL_SET (scm_source_properties (expr), + SCM_EXPANDED_REF (vmem, TOPLEVEL_REF, NAME), + expand (CADDR (expr), env)); + case SCM_EXPANDED_MODULE_REF: + return MODULE_SET (scm_source_properties (expr), + SCM_EXPANDED_REF (vmem, MODULE_REF, MOD), + SCM_EXPANDED_REF (vmem, MODULE_REF, NAME), + SCM_EXPANDED_REF (vmem, MODULE_REF, PUBLIC), + expand (CADDR (expr), env)); + default: + syntax_error (s_bad_variable, variable, expr); + } +} + + + + +SCM_DEFINE (scm_macroexpand, "macroexpand*", 1, 0, 0, + (SCM exp), + "Expand the expression @var{exp}.") +#define FUNC_NAME s_scm_macroexpand +{ + return expand (exp, scm_current_module ()); +} +#undef FUNC_NAME + + + + +#define DEFINE_NAMES(type) \ + { \ + static const char *fields[] = SCM_EXPANDED_##type##_FIELD_NAMES; \ + exp_field_names[SCM_EXPANDED_##type] = fields; \ + exp_names[SCM_EXPANDED_##type] = SCM_EXPANDED_##type##_TYPE_NAME; \ + exp_nfields[SCM_EXPANDED_##type] = SCM_NUM_EXPANDED_##type##_FIELDS; \ + } + +static SCM +make_exp_vtable (size_t n) +{ + SCM layout, printer, name, code, fields; + + layout = scm_string_to_symbol + (scm_string_append (scm_make_list (scm_from_size_t (exp_nfields[n]), + scm_from_locale_string ("pw")))); + printer = SCM_BOOL_F; + name = scm_from_locale_symbol (exp_names[n]); + code = scm_from_size_t (n); + fields = SCM_EOL; + { + size_t m = exp_nfields[n]; + while (m--) + fields = scm_cons (scm_from_locale_symbol (exp_field_names[n][m]), fields); + } + + return scm_c_make_struct (scm_exp_vtable_vtable, 0, 5, + SCM_UNPACK (layout), SCM_UNPACK (printer), SCM_UNPACK (name), + SCM_UNPACK (code), SCM_UNPACK (fields)); +} + +void +scm_init_expand () +{ + size_t n; + SCM exp_vtable_list = SCM_EOL; + + DEFINE_NAMES (VOID); + DEFINE_NAMES (CONST); + DEFINE_NAMES (PRIMITIVE_REF); + DEFINE_NAMES (LEXICAL_REF); + DEFINE_NAMES (LEXICAL_SET); + DEFINE_NAMES (MODULE_REF); + DEFINE_NAMES (MODULE_SET); + DEFINE_NAMES (TOPLEVEL_REF); + DEFINE_NAMES (TOPLEVEL_SET); + DEFINE_NAMES (TOPLEVEL_DEFINE); + DEFINE_NAMES (CONDITIONAL); + DEFINE_NAMES (APPLICATION); + DEFINE_NAMES (SEQUENCE); + DEFINE_NAMES (LAMBDA); + DEFINE_NAMES (LAMBDA_CASE); + DEFINE_NAMES (LET); + DEFINE_NAMES (LETREC); + DEFINE_NAMES (DYNLET); + + scm_exp_vtable_vtable = + scm_make_vtable (scm_from_locale_string (SCM_VTABLE_BASE_LAYOUT "pwuwpw"), + SCM_BOOL_F); + + for (n = 0; n < SCM_NUM_EXPANDED_TYPES; n++) + exp_vtables[n] = make_exp_vtable (n); + + /* Now walk back down, consing in reverse. */ + while (n--) + exp_vtable_list = scm_cons (exp_vtables[n], exp_vtable_list); + + scm_c_define ("%expanded-vtables", exp_vtable_list); + +#include "libguile/expand.x" +} + +/* + Local Variables: + c-file-style: "gnu" + End: +*/ |