[Yaml-core] equality and transfer methods that are too smart

[Clark C . E. <cc...@cl...>]

Oren has brought up a serious point that
we have to seriously consider.  At the 
information model level, it would be nice
to be able to assert that two scalars are
equal if their strings are.  

Obviously this won't work... so we need to
further complicate the transfer method by
extending each one with a an equivalence
relation requirement... given any two
string representations, it must provide
for a way to see if those two strings
are equivalent.  Quite clearly we know
that two strings are not equivalent when
they have a differnt string representation.

I don't like this, but I don't see any 
alternative.  Unfortunately, it means 
that there is *no way* to ensure that
a mapping is valid if it has keys that
are not part of a registered transfer
method...  Hmm.  I guess we can use
a fall back in this case, and just do
a string comparison.  

....

That said... it's complicated enough
when scalars stay scalars.  Now, if
we have scalars turning into collections...
that's a horse of a new level of 
complexity.... and I'm not sure that
we are prepared to handle it at this
point.  

Therefore, I'm asking that we table
all of our cool collection short-hands
till the next version.

....

Also, I'm proposing that "quoted" 
scalars be added back in to the
syntax productions.  It's clear 
that we need them, and they are
*way* too magical to be kept as
a transfer method.

Best,

Clark