Re: Senarios for feature matching

[Al Gilman <asgilman@xxxxxxxxxxxxxxxx>]

One scenario for feature value comparison (feature expression
reduction) is that the registration contains:

* A grammar for feature expressions.

* [An alternate grammar for the representation of said feature
expressions in URLs]

* The base URL for a public expression evaluator for expressions
dealing in this characteristic.

This is the simplest way to support an operationally-defined
feature class across the whole Internet.

This give the maximum performance on expressivity and reach
scales.  CPU and wall-clock time to complete negotiation will
be better for other techniques.

Some effort will be required to police the consistency of
expression evaluations and continuity of service of the
expression evaluation resource.

Al Gilman