view lwlib/lw_cmdline.h @ 434:052c5f335a92

Fix bug in like terms collection in expression simplification Like term collection would lose the actual "variable" part of the term if the second term collected happened to have no coefficient. This would cause the expression to take the value of the calculated coefficient which is obviously wrong. Thanks to hider <stego@satx.rr.com> for reporting the bug and providing a proper test case. Observation: this bug has been present since the first pre-release of lwtools 3.0 when the algebraic expression system was introduced. Apparently people tend not to create expressions that trigger the like terms handler. The specific conditions require the symbol to be undefined and the second operand to the addition has to have no coefficient so it's likely a fairly rare scenario. Still, it is somewhat surprising that nobody tripped on it before now.
author William Astle <lost@l-w.ca>
date Mon, 23 Jan 2017 22:58:36 -0700
parents 8e25147c2aa8
children
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/*
lw_cmdline.h

Copyright © 2010 William Astle

This file is part of LWTOOLS.

LWTOOLS is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.

This program 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 General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
*/

/*

This argument parser is patterned after argp from the gnu C library but
has much of the functionality removed. It is provided here because not
every system has glibc.

Most notably, it does not support option groups or i18n.

*/

#ifndef ___lw_cmdline_h_seen___
#define ___lw_cmdline_h_seen___

struct lw_cmdline_options
{
	char *name;
	int key;
	char *arg;
	int flags;
	char *doc;
};

enum
{
	lw_cmdline_opt_optional = 1,
	lw_cmdline_opt_hidden = 2,
/*	lw_cmdline_opt_alias = 4,*/
/*	lw_cmdline_opt_nousage = 0x10,*/
	lw_cmdline_opt_doc = 0x80
};

enum
{
	lw_cmdline_err_unknown = -1
};

enum
{
	lw_cmdline_key_arg = -1,
	lw_cmdline_key_end = 0
};

struct lw_cmdline_parser
{
	struct lw_cmdline_options *options;
	int (*parser)(int key, char *arg, void *input);
	char *args_doc;
	char *doc;
	char *program_version;
};

int lw_cmdline_parse(struct lw_cmdline_parser *parser, int argc, char **argv, unsigned flags, int *arg_index, void *input);

#endif /* ___lw_cmdline_h_seen___ */