An implementation of Unix dc and POSIX bc with GNU and BSD extensions. Finished, but well-maintained.
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/*
* *****************************************************************************
*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2018-2021 Gavin D. Howard and contributors.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* *****************************************************************************
*
* The lexer for dc.
*
*/
#if DC_ENABLED
#include <ctype.h>
#include <dc.h>
#include <vm.h>
bool dc_lex_negCommand(BcLex *l) {
char c = l->buf[l->i];
return !BC_LEX_NUM_CHAR(c, false, false);
}
static void dc_lex_register(BcLex *l) {
if (DC_X && isspace(l->buf[l->i - 1])) {
char c;
bc_lex_whitespace(l);
c = l->buf[l->i];
if (!isalnum(c) && c != '_')
bc_lex_verr(l, BC_ERR_PARSE_CHAR, c);
l->i += 1;
bc_lex_name(l);
}
else {
bc_vec_popAll(&l->str);
bc_vec_pushByte(&l->str, (uchar) l->buf[l->i - 1]);
bc_vec_pushByte(&l->str, '\0');
l->t = BC_LEX_NAME;
}
}
static void dc_lex_string(BcLex *l) {
size_t depth = 1, nls = 0, i = l->i;
char c;
l->t = BC_LEX_STR;
bc_vec_popAll(&l->str);
for (; (c = l->buf[i]) && depth; ++i) {
if (c == '\\') {
c = l->buf[++i];
if (!c) break;
}
else {
depth += (c == '[');
depth -= (c == ']');
}
nls += (c == '\n');
if (depth) bc_vec_push(&l->str, &c);
}
if (BC_ERR(c == '\0' && depth)) {
l->i = i;
bc_lex_err(l, BC_ERR_PARSE_STRING);
}
bc_vec_pushByte(&l->str, '\0');
l->i = i;
l->line += nls;
}
void dc_lex_token(BcLex *l) {
char c = l->buf[l->i++], c2;
size_t i;
for (i = 0; i < dc_lex_regs_len; ++i) {
if (l->last == dc_lex_regs[i]) {
dc_lex_register(l);
return;
}
}
if (c >= '"' && c <= '~' &&
(l->t = dc_lex_tokens[(c - '"')]) != BC_LEX_INVALID)
{
return;
}
// This is the workhorse of the lexer.
switch (c) {
case '\0':
case '\n':
case '\t':
case '\v':
case '\f':
case '\r':
case ' ':
{
bc_lex_commonTokens(l, c);
break;
}
case '!':
{
c2 = l->buf[l->i];
if (c2 == '=') l->t = BC_LEX_OP_REL_NE;
else if (c2 == '<') l->t = BC_LEX_OP_REL_LE;
else if (c2 == '>') l->t = BC_LEX_OP_REL_GE;
else bc_lex_invalidChar(l, c);
l->i += 1;
break;
}
case '#':
{
bc_lex_lineComment(l);
break;
}
case '.':
{
c2 = l->buf[l->i];
if (BC_NO_ERR(BC_LEX_NUM_CHAR(c2, true, false)))
bc_lex_number(l, c);
else bc_lex_invalidChar(l, c);
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
{
bc_lex_number(l, c);
break;
}
case '[':
{
dc_lex_string(l);
break;
}
default:
{
bc_lex_invalidChar(l, c);
}
}
}
#endif // DC_ENABLED