Re: yaml module feature question about String Tag

NAKAMURA, Hiroshi wrote:

> YAML.load([%q(- \t), %q(- '\t'), %q(- "\t"), %q(- !str \t)].join("\n"))
> => ["\\t", "\\t", "\t", "\\t"]
>
> Note: only the 3rd String notation is "\t", not "\\t" that I expected.

This appears to be correct translation.  From Section 2.3 of 
http://yaml.org/spec/ :

    YAML's flow scalars include the plain style (most examples thus far)
    and quoted styles. The double quoted style provides escape
    sequences. Single quoted style is useful when escaping is not
    needed. All flow scalars can span multiple lines; intermediate
    whitespace is trimmed to a single space.

_why