113 lines
2.5 KiB
C
113 lines
2.5 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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scm *
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string (scm *x) ///((arity . n))
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{
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return make_string (x);
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}
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scm *
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string_append (scm *x) ///((arity . n))
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{
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scm *p = &scm_nil;
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while (x != &scm_nil)
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{
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scm *s = car (x);
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assert (s->type == STRING);
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p = append2 (p, s->string);
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x = cdr (x);
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}
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return make_string (p);
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}
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scm *
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list_to_string (scm *x)
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{
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return make_string (x);
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}
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scm *
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string_length (scm *x)
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{
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assert (x->type == STRING);
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return make_number (length (x->string)->value);
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}
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scm *
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string_ref (scm *x, scm *k)
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{
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assert (x->type == STRING);
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assert (k->type == NUMBER);
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scm n = {NUMBER, .value=k->value};
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return make_char (list_ref (x->string, &n)->value);
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}
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scm *
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substring (scm *x) ///((arity . n))
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{
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assert (x->type == PAIR);
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assert (x->car->type == STRING);
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scm *s = x->car->string;
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assert (x->cdr->car->type == NUMBER);
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int start = x->cdr->car->value;
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int end = length (s)->value;
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if (x->cdr->cdr->type == PAIR) {
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assert (x->cdr->cdr->car->type == NUMBER);
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assert (x->cdr->cdr->car->value <= end);
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end = x->cdr->cdr->car->value;
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}
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int n = end - start;
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while (start--) s = s->cdr;
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scm *p = &scm_nil;
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while (n-- && s != &scm_nil) {
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p = append2 (p, cons (make_char (s->car->value), &scm_nil));
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s = s->cdr;
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}
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return make_string (p);
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}
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scm *
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number_to_string (scm *x)
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{
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assert (x->type == NUMBER);
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int n = x->value;
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scm *p = n < 0 ? cons (make_char ('-'), &scm_nil) : &scm_nil;
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do {
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p = cons (make_char (n % 10 + '0'), p);
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n = n / 10;
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} while (n);
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return make_string (p);
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}
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scm *
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string_to_symbol (scm *x)
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{
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assert (x->type == STRING);
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return make_symbol (x->string);
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}
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scm *
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symbol_to_string (scm *x)
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{
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assert (x->type == SYMBOL);
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return make_string (x->string);
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}
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