Re: notes on conneg-feature-hash-02

At 19:30 14/07/99 +0200, Maurizio Codogno wrote:
>Hi all.
>I have also read conneg-feature-hash-02...
>
>sect. 3.2 : I am not sure what happens if we have an URI (either 
>direct or dereferenced through a hash) and some explicit feature.
>My personal logic will say that the latter overrides the "defaults"
>provided, but I am not sure about it and I think that some word could
>clarify the issue.

Thank you for raising this issue.  In fact, there is no concept of
"default" and "override" in the current notation.  I propose to add
something along the following lines at the end of the introductory text in
section 3, just before section 3.1 (since it applies to both hash and URI
forms):

  NOTE:  where a feature set reference is used, 
  its meaning is defined by substitution of the 
  referenced feature expression into the 
  referencing expression.  When all references 
  have been thus replaced, the result is 
  interpreted as a normal feature expression.

  In particular, if a referenced feature 
  expression contains some feature tag that is 
  also constrained by the referencing expression, 
  the constraints are interpreted per [1], 
  without regard for their origin.  e.g. (using 
  some notation introduced below):
    (& (pix-x=100) (pix-y<=300) (h.1234567890) )
  where (h.1234567890) resolves to:
    (& (pix-x<=200) (pix-y<=150) )
  yields a result equivalent to:
    (& (pix-x=100) (pix-y<=150) )

Does this help to make the intent clearer?

#g

------------
Graham Klyne
([email protected])