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Roy's definition of a REST resource as a "Curried" form of ftrr:IR

From: David Booth <david@dbooth.org>
Date: Fri, 04 Mar 2011 13:18:28 -0500
To: nathan@webr3.org
Cc: AWWSW TF <public-awwsw@w3.org>
Message-ID: <1299262708.2525.30494.camel@dbooth-laptop>

Have you looked at the definition of IR that I proposed a while back?
It is logically equivalent to Roy's definition of a REST resource, but
it pulls the Request parameter out earlier.  Roy's notion of a REST
resource, roy:RR, is basically a "Curried" form of ftrr:IR
http://en.wikipedia.org/wiki/Currying :

  for any Time t and Request req, ftrr:IR(t, req) = roy:RR(t)(req).

If one wishes to nitpick, Roy does not explicitly say that the second
step of selecting a representation (via content negotiation) is
functional, but I think it is implied:
More precisely, a resource R is a temporally varying membership function
MR(t), which for time t maps to a set of entities, or values, which are
equivalent. The values in the set may be resource representations and/or
resource identifiers. [ . . . ]

This abstract definition of a resource . . . allows late binding of the
reference to a representation, enabling content negotiation to take
place based on characteristics of the request.

Furthermore, the discussion of content negotiation in section 12.1 of
RFC 2616 also implies (but does not explicitly say) that it is
   Selection [of the best representation for a response] is based on
   the available representations of
   the response (the dimensions over which it can vary; e.g. language,
   content-coding, etc.) and the contents of particular header fields in
   the request message or on other information pertaining to the request
   (such as the network address of the client).

I've also left out some details about "Agent-driven content negotiation"
and the 300 (Multiple Choices) response code, because they don't have a
material impact on this, but again if one wishes to nitpick, they would
have to be accounted.

David Booth, Ph.D.

Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.
Received on Friday, 4 March 2011 18:18:56 UTC

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