d34dba24f2
* mes.c [QUASISYNTAX]: New switch. Default off. (builtin_eval) [QUASISYNTAX]: Handle syntax, unsyntax, quasisyntax. * quasiquote.c (syntax, unsyntax, unsyntax_splicing, eval_quasisyntax, add_unsyntaxers) [QUASISYNTAX]: Available only.
117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
/* -*-comment-start: "//";comment-end:""-*-
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* Mes --- Maxwell Equations of Software
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* Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
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*
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* This file is part of Mes.
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*
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* Mes is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* Mes is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Mes. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if QUASIQUOTE
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scm *add_environment (scm *a, char const *name, scm *x);
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scm *
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unquote (scm *x) ///((no-environment))
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{
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return cons (&symbol_unquote, x);
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}
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scm *
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unquote_splicing (scm *x) ///((no-environment))
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{
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return cons (&symbol_unquote_splicing, x);
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}
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scm *
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eval_quasiquote (scm *e, scm *a)
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{
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if (e == &scm_nil) return e;
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else if (atom_p (e) == &scm_t) return e;
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else if (eq_p (car (e), &symbol_unquote) == &scm_t)
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return builtin_eval (cadr (e), a);
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else if (e->type == PAIR && e->car->type == PAIR
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&& eq_p (caar (e), &symbol_unquote_splicing) == &scm_t)
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return append2 (builtin_eval (cadar (e), a), eval_quasiquote (cdr (e), a));
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return cons (eval_quasiquote (car (e), a), eval_quasiquote (cdr (e), a));
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}
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scm *
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the_unquoters = &scm_nil;
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scm *
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add_unquoters (scm *a)
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{
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if (the_unquoters == &scm_nil)
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the_unquoters = cons (cons (&symbol_unquote, &scm_unquote),
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cons (cons (&symbol_unquote_splicing, &scm_unquote_splicing),
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&scm_nil));
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return append2 (the_unquoters, a);
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}
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#else // !QUASIQUOTE
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scm*add_unquoters (scm *a){}
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scm*eval_quasiquote (scm *e, scm *a){}
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#endif // QUASIQUOTE
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#if QUASISYNTAX
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scm *
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syntax (scm *x)
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{
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return cons (&symbol_syntax, x);
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}
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scm *
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unsyntax (scm *x) ///((no-environment))
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{
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return cons (&symbol_unsyntax, x);
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}
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scm *
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unsyntax_splicing (scm *x) ///((no-environment))
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{
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return cons (&symbol_unsyntax_splicing, x);
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}
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scm *
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eval_quasisyntax (scm *e, scm *a)
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{
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if (e == &scm_nil) return e;
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else if (atom_p (e) == &scm_t) return e;
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else if (eq_p (car (e), &symbol_unsyntax) == &scm_t)
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return builtin_eval (cadr (e), a);
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else if (e->type == PAIR && e->car->type == PAIR
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&& eq_p (caar (e), &symbol_unsyntax_splicing) == &scm_t)
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return append2 (builtin_eval (cadar (e), a), eval_quasisyntax (cdr (e), a));
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return cons (eval_quasisyntax (car (e), a), eval_quasisyntax (cdr (e), a));
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}
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scm *
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add_unsyntaxers (scm *a)
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{
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a = cons (cons (&symbol_unsyntax, &scm_unsyntax), a);
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a = cons (cons (&symbol_unsyntax_splicing, &scm_unsyntax_splicing), a);
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return a;
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}
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#else // !QUASISYNTAX
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scm*syntax (scm *x){}
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scm*unsyntax (scm *x){}
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scm*unsyntax_splicing (scm *x){}
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scm*add_unsyntaxers (scm *a){}
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scm*eval_unsyntax (scm *e, scm *a){}
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scm*eval_quasisyntax (scm *e, scm *a){}
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#endif // !QUASISYNTAX
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