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v11-03 COMMENT: 3.5 Terminology, Resource entity

From: Koen Holtman <koen@win.tue.nl>
Date: Sun, 19 May 1996 17:56:38 +0200 (MET DST)
Message-Id: <199605191556.RAA14441@wsooti04.win.tue.nl>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com

I just spent half a day being completely confused over what a
`resource entity' is or should be.  The question is: if I replace the
English text bound to a generic resource by a version of this English
text with some spelling errors corrected, have I
  a) changed the value of the existing English text resource entity
or
  b) replaced the existing English text resource entity by another 
     English text resource entity?

Under a) a resource entity is something like a variable or container.
Under b) a resource entity is something like a value or constant.

The spec _mostly_ uses `resource entity' in the a) sense.  The
definition of the term, however, leads one to believe that it is b),
and this is very confusing.

The draft defines the term as follows:

resource entity
  A specific representation, rendition, encoding, or presentation of a
    ^^^^^^^^   
  network data object or service, either a plain resource or a specific
  member of a generic resource.  

Now, use of `specific' seems to imply that a resource entity is a
value.

                                A resource entity might be identified
  by a URI, or by the combination of a URI and a variant-ID, or by the
  combination of a URI and some other mechanism. An plain resource MUST
  be bound to a single resource entity at any instant in time.

this latter part seems to imply that it is a variable.

After two hours of trashing around, I came up with the following fix:

 resource entity
  A   representation, rendition,
    ^
  encoding, or presentation of a network data object or service,
  either a plain resource or a specific member of a generic resource.
  This representation may change over time.  
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  A resource entity might be identified by a URI, or by the
  combination of a URI and a variant-ID, or by the combination of a
  URI and some other mechanism. An plain resource MUST be bound to a
  single resource entity at any instant in time.

Note that this does not make a resource entity a `real variable', it
makes it `a value that sometimes changes'.  Defining it as a `real
variable' (or `placeholder' or `container') would be mathematically
cleaner, but would also require _very_ extensive edits to the spec (I
spent an hour trying to make these edits and got nowhere near
finished).

Koen.
Received on Sunday, 19 May 1996 09:00:37 EDT

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