dumper: don't quote strings with # without need

[vcache]

According to spec a sharp symbol may be used within a key with plain style (i.e. without quotes) in certain conditions:

[130]   ns-plain-char(c) ::=   ( ns-plain-safe(c) - “:” - “#” )
                             | ( /* An ns-char preceding */ “#” )
                             | ( “:” /* Followed by an ns-plain-safe(c) */ )

That's handy when key contains URI like so:

uris:
  - http://example.com/page#anchor: some-example

[puzrin]

1. Term "fix" usually means something was broken (invalid output). As far as i understand, output without this update is valid. So, that's not fix but improvement.
2. Need test to demonstrate use cases, why this change done.

[puzrin]

((c !== CHAR_SHARP) || (prev && isPrintable(prev)));

I'd use more scopes to simplify understanding.

[vcache]

Thanks for your review. You right, actually it is not a bug fix but proposition for more efficient usage of YAML specification. I've added some tests and made code more readable.

[puzrin]

• please move tests here with Issue/PR number
• squash all and change commit name to "dumper: don't quote strings with # without need" - that's more informative.

Everything else seems ok.

[puzrin]

Thank you!

[Himura2la]

@vcache, The test does not test anything. You should not parse the sample YAML if you are testing how it's dumped. I changed the test like this:

test('Don\'t quote strings with # without need', function () {
  var required = readFileSync(require('path').join(__dirname, '/0521.yml'), 'utf8');
  var data = {
    'http://example.com/page#anchor': 'no#quotes#required',
    'parameter#fallback': 'quotes #required',
    'foo #bar': 'key is quoted'
  };
  var actual = yaml.safeDump(data);
  assert.equal(actual, required);
});

Now it fails. The http://example.com/page#anchor key is being quoted (because of a colon)