@ingydotnet this looks fine to me, do you have opinions? Also, do you know why Travis isn't running against these PRs?

sorry, I forgot ignore the white space at first. so I update the PR .

I found another bug.

[1:0]

This is a valid yaml document, but libyaml report found unexpected ':'

1:0 is a sexagesimal . See http://yaml.org/spec/1.1/ Example 2.19. Integers

canonical: 12345
decimal: +12,345
sexagesimal: 3:25:45
octal: 014
hexadecimal: 0xC

I'd like to see tests added for these things.

We might want to split this into 2 PRs.

URLs are probably a more common reason for ':' in plain scalar, than
sexagesimal. (I want to drop sexagesimal as a suggested default behavior in
1.3).

Failing tests:

Unicode anchors:

foo: &döt
  bar: 123
baz: *döt

Colon in flow plain:

key: {url: http://example.com}

I remove the last commit just now , and would make a new pr for ':' in plain scalar.