I've been playing around with implementation of a very simplistic YPath lib for Ruby. It's nothing anyone would consider conforming to a definitive YPath spec. Rather, it's just so there is at least something that basically works so I can use it with YES schema project. In other words I am throwing together a hack as a stand in until a *real* YPath library comes along. -- I so wish there was already a YPath library out there I could use.

In any case, working on this I realize that any YPath spec that's more or less patterned after XPath (which always seems to be the idea) is going to have some limitations. An obvious example is a YPath for mapping keys of some odd type. That makes me suspect of the the whole idea of an XPath-like YPath. So, what if YPath where just a YAML document with "match slots"? e.g. given a YAML document

    ---
    a: 1
    b: 2

YPath document:

    --- !ypath
    a: <?>

Then in code something like:

   ypath = YPath.new(ypath_document)
   ypath.match(yaml_document)

The return value would be a list containing 1 or the YAML node for 1.

Nod sure to search every node though (rather than just root), maybe something like

    --- !ypath-any
    a: <?>

Or

    --- !ypath
    <*>:
      a: <?>

Thoughts?