choice -- the dyslexic option parser

Do what I mean, not what I type, dammit! -- me, every time.

Choice is a parser for command-line options with support for fuzzy option matching and generating command completion.

It is just two files and not even a thousand NLOC with all the bells and whistles you can ask for.

Why?

I spend most of my day in xterm and OS X' Terminal. There's a lot of typing going on. There are so may awesome command-line utilities out there, but I wish there were more of them.

As a heavy command-line user, I've grown pretty accustomed to the behaviour of getopt. The combination of long and short options works surprisingly well. I don't care what parses the options.

But when I write yet-another-utility-program, what I'm often struggling with is designing the command-line switches for a great experience. More often than not, I just want to get the job done, and couldn't care less about the usability.

But usability matters. So to solve the problem once and for all, here is one more option parser. There's no excuse anymore for those crufty while-switch loops.

I can not recall how many ad-hoc option parsers I have written, but it's probably been a few too many. You start with a simple loop, looking for the one single flag you program understands and it goes downhill from there. After a short struggle, you end up sucking it up to getopt and its not quite portable cousin getopt_long and that is that.

Examples

Let's drive this home with a few examples.

#include "choice.h"
#include <stdbool.h>

static struct {
  bool verbose;
  const char* required;
  long optional;
} config = {
  false,
  NULL,
  -1
};

static option_t options[] = {
  { "verbose", "enable verbose stuff", 'v', 0, &choice_true, &config.verbose },
  { "required", "required arg", 'r', OPTION_REQARG, &choice_str, &config.required },
  { "optional", "optional arg", 'o', OPTION_OPTARG, &choice_long, &config.optional },
  OPTION_EOL
};

int main( int argc, const char* argv[] ) {
  option_parse( options, argc, argv );
  printf( "verbose: %s\n", config.verbose ? "true" : "false" );
  printf( "required: %s\n", config.required );
  printf( "optional: %li\n", config.optional );
  return 0;
}

$ example
verbose: false
required: (null)
optional: -1
$ example --verbose --required=test
verbose: true
required: test
optional: -1
$ example -vrtest
verbose: true
required: test
optional: -1
$ example --vebrose --requird derp
verbose: true
required: derp
optional: -1
$ example --verb --opt
verbose: true
required: (null)
optional: 0

Credits

Inspiration for this library was taken from @isaacs' npm isntall and @visionmedia's commander.c. The levenshtein implementation was adapted and extended from @schuyler's ruby module.
Thank you!

License

Copyright © 2013, Jonas Pommerening [email protected] All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. 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 OWNER 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.