118 lines
2.6 KiB
C
118 lines
2.6 KiB
C
/* reader.c: Stream reader implementation
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* Created: 2026-02-04
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* Author: Aryadev Chavali
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* License: See end of file
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* Commentary:
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*/
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#include <ctype.h>
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#include <string.h>
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#include <alisp/reader.h>
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const char *read_err_to_cstr(read_err_t err)
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{
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switch (err)
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{
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case READ_ERR_OK:
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return "OK";
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case READ_ERR_EOF:
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return "EOF";
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case READ_ERR_UNKNOWN_CHAR:
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return "UNKNOWN_CHAR";
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default:
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FAIL("Unreachable");
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}
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}
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// Accepted characters for symbols.
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static const char *SYMBOL_CHARS =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!$%&*+,-./"
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":<=>?@\\^_`{|}~0123456789";
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// Little predicate using SYMBOL_CHARS
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bool is_sym(char c)
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{
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return strchr(SYMBOL_CHARS, c) != NULL;
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}
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void skip_comments_and_whitespace(stream_t *stream)
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{
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for (char c = stream_peek(stream); c != '\0' && (isspace(c) || c == ';');
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c = stream_peek(stream))
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{
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stream_while(stream, " \t\n\0");
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if (stream_peek(stream) == ';')
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{
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// Skip till newline
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stream_till(stream, "\n");
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}
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}
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}
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read_err_t read_int(sys_t *, stream_t *, lisp_t **)
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{
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TODO("read_int: not implemented");
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}
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read_err_t read_sym(sys_t *, stream_t *, lisp_t **)
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{
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TODO("read_sym: not implemented");
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}
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read_err_t read_list(sys_t *, stream_t *, lisp_t **)
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{
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TODO("read_list: not implemented");
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}
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read_err_t read_vec(sys_t *, stream_t *, lisp_t **)
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{
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TODO("read_vec: not implemented");
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}
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read_err_t read_all(sys_t *sys, stream_t *stream, vec_t *out)
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{
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while (!stream_eoc(stream))
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{
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lisp_t *item = NIL;
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read_err_t err = read(sys, stream, &item);
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if (err)
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return err;
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else
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vec_append(out, &item, sizeof(item));
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}
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return READ_ERR_OK;
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}
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read_err_t read(sys_t *sys, stream_t *stream, lisp_t **ret)
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{
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skip_comments_and_whitespace(stream);
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if (stream_eoc(stream))
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return READ_ERR_EOF;
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char c = stream_peek(stream);
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if (isdigit(c))
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return read_int(sys, stream, ret);
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else if (is_sym(c))
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return read_sym(sys, stream, ret);
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else if (c == '(')
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return read_list(sys, stream, ret);
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else if (c == '[')
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return read_vec(sys, stream, ret);
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else
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return READ_ERR_UNKNOWN_CHAR;
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}
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/* Copyright (C) 2026 Aryadev Chavali
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License Version 2 for
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* details.
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* You may distribute and modify this code under the terms of the GNU General
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* Public License Version 2, which you should have received a copy of along with
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* this program. If not, please go to <https://www.gnu.org/licenses/>.
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*/
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