psych tries to parse leading '%' after '---' as directives

[ericpromislow]

According to the YAML 1.2 grammar:

[209] l-directive-document ::= l-directive+ l-explicit-document ;
[82] l-directive ::= “%” ( ns-yaml-directive | ns-tag-directive | ns-reserved-directive ) s-l-comments ;
[208] l-explicit-document ::= c-directives-end ( l-bare-document | ( e-node s-l-comments ) ) ;
[203] c-directives-end ::= “-” “-” “-”

Using Ruby 1.9.3, Yaml 1.3.4 (also happens with Ruby 2.1.5, YAML2.0.5):
irb(main):009:0> YAML.load("---\nx")
=> "x" # Correct
irb(main):010:0> YAML.load("---\n%x")
Psych::SyntaxError: (): found uknown directive name while scanning a directive at line 2 column 1
from /usr/lib/ruby/1.9.1/psych.rb:203:in parse' from /usr/lib/ruby/1.9.1/psych.rb:203:inparse_stream'
from /usr/lib/ruby/1.9.1/psych.rb:151:in parse' from /usr/lib/ruby/1.9.1/psych.rb:127:inload'
from (irb):10
from /usr/bin/irb:12:in `

'

I see the 'uknown' typo has been fixed.

[tenderlove]

Psych uses libyaml as it's parser, and libyaml only supports YAML 1.1 grammar right now. Once libyaml is updated to support 1.2, then Psych will support 1.2. Thanks!