yamlson

#!/usr/bin/env python

import sys
import json
import yaml
import argparse
import functools


def main(args):
    opts = parse_cli(args[1:])
    reader = json.load if opts.reverse else yaml.load
    json_encoder = functools.partial(json.dumps, separators=(',', ':'))
    writer = yaml.safe_dump if opts.reverse else json_encoder
    conversion = lambda fd: sys.stdout.write(writer(reader(fd)) + '\n')
    if opts.files is None:
        files = [sys.stdin]
        action = conversion
    else:
        files = opts.files
        action = lambda fn: with_file(fn, conversion)
    for fd in files:
        try:
            action(fd)
        except KeyboardInterrupt:
            return 1
        except Exception as err:
            sys.stderr.write('ignoring error %s\n', err)
            sys.stderr.flush()
    return 0


def with_file(filename, action):
    with open(filename, 'rb') as fd:
        return action(fd)


def parse_cli(args):
    parser = argparse.ArgumentParser(
        description='convert from YAML to JSON and back')
    parser.add_argument(
        '-r', '--reverse',
        action='store_true',
        help='convert from JSON to YAML')
    parser.add_argument(
        'files',
        nargs='*',
        metavar='file',
        help='filenames to convert (default STDIN)')
    return parser.parse_args(args)

if __name__ == '__main__':
    sys.exit(main(sys.argv))