Re: A clarification on Capabilities, Parameters, createParameters, and filterParameters.

Peter Thatcher said: 

This could be done entirely in JS, but for simple use cases, that's kind of a pain, so we introduce a second convenience function: filterParameters.
It has a simple meaning:

(1) filterParameters(createParameters(), C) == createParameters(C)

[BA] It makes sense to me that calling a local filterParameters function on locally created parameters along with remote capabilities would produce the same result as calling the local createParameters function on those same remote capabilities. 

However, there is another use of filterParameters in Example 8 of the Editor's draft, which is calling the local filterParameters function on parameters created on a remote system and (implicitly) filtering them through the local capabilities. 

For this case, I am wondering if there is an equivalent relationship to equation (1) above.  For example, do we believe that the following relationship holds? 

(2) filterParameters(remoteCreateParameters()) == remoteCreateParameters(localCapabilities)

The above relationship seems to require some additional assumptions beyond the first one, which is that the local filterParameters function is compatible with the remote createParameters function.  

[Peter] 1.  Exchange capabilities, and then parameters use createParameters (2 round trips, but extremely easy). 

[BA] If relationship (2) holds, it would seem that exchanging capabilities would be sufficient without having to exchange parameters over the wire, because those parameters are derivable on the remote system without having to send them.

Received on Saturday, 10 May 2014 20:27:23 UTC