Re: URIs, names and well known RDDL names, was: Re: Quick edit

[ht@cogsci.ed.ac.uk (Henry S. Thompson)]

John Aldridge <john.aldridge@informatix.co.uk> writes:

> At 10:24 10/01/2001 +0000, Henry S. Thompson wrote:
> >Quick followup -- I checked the XLink spec, and it's pretty clear that
> >
> >'role' is for properties of the target resource
> >'arcrole' is for properties of the target wrt to the link
> >
> >so my/Tim/Jason's proposal, that 'role' be the primary xlink attribute
> >we use to distinguish on rddl:resource from another, and 'arcrole' be
> >the secondary one, seems clearly preferrable to the status quo.
> 
> I'm missing something here...  To give an analogy, this seems to be like 
> saying, when programming in C,
> 
> struct {
>     int a;
>     int b;
>     double c;
> } rddf;
> 
> that the primary access to struct members should be by writing their 
> datatype (int/double):
> 
>     rddf.double
> 
> and that use of the member name (a/b/c) should only be used if necessary to 
> disambiguate:
> 
>     rddf.int[sort=b];

I think the analogy is flawed, but I'll try to explain in these terms
anyway.  What we're dealing with is a situation where looking a
variable up on the stack is expensive, and in many cases we only care
about the values of variables of a particular type.  So we establish a 
convention that we will name our variables using the following
strategy:

  If there is only one variable of a particular type in a struct,
  we'll use its type name (read namespaceURI) as its name (read
  xlink:role);

  If there are two or more variables of a particular type in a struct, 
  we'll use a combination of its type name and its function (read
  xlink:arcrole) as its name.

  So we get

  struct {
    double double;
    int int.a;
    int int.b;
  } rddf;

  Now we can decide which variables to evaluate (I told you the
  analogy was flawed :-) based on their names.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
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