Function to get JSON type

[gregsdennis]

This StackOverflow question needs the ability to isolate values of a given type. I think this would make a good function.

$.foo[?type(@)=='object']

The function would return a string (one of object, array, number, string, boolean, null) that indicates the value type of the parameter, which is a ValueType.

Not sure if true and false should be combined into boolean or not. Technically, these are merely tokens, not actual "boolean" values, though the association is strong.

[cabo]

Definitely useful.
I believe the majority of users of JSONPath would perceive true and false to be part of a common type boolean, so I would design this function extensions to the principle of least surprise.

This issue is now listed in #480.

[gregsdennis]

I don't think linking this issue in a list warrants closing it. This still remains unresolved.

[cabo]

Like all other issues marked revisit-after-base-done.
We had this discussion.

[gregsdennis]

Related to #172