[DAS2] Identifiers and URIs

[Steve Chervitz]

All DAS/2 elements are identified with a uri attribute, but their
documentation isn't consistent. So I'm recommending this be tighted up a
bit. Some examples from das2_schemas.rnc:

  # URL pointing directly to the given TYPE
  uri,

  # URL pointing directly to the feature
  uri,

  # URL for the actual sequence data.  It implements the DAS2
  # sequence request interface.
  uri,

  # A unique identifier for this coordinate.
  # This is an abstract identifier and might not be resolvable.
  # Two coordinates are the same if and only if they have the
  # same URI.
  uri,

  # unique URI for the SOURCE
  # Each source URI must be unique in sources list
  uri,

I propose that all such comments have a consistent wording. How about this:

  # A unique identifier for this [object-type]
  uri

If the entity is resolvable, then add:

  # This URL is resolvable to this [object-type] from a DAS/2 server.

Otherwise:

  # This is an abstract identifier and might not be resolvable.


In the abbreviations section of the rnc, the uri itself is described as:

  # URI to an object defined by the DAS spec
  uri = attribute uri { text }

I'd change this to:

  # URL used to identify an object defined in a DAS/2 document.


There are some places in the HTML retrieval document that could be updated
to state 'uri' instead of 'id'. In the sources section:

  "All identifiers and href attributes ... follow the XML Base ..."

Recommended change:

  "All uri and href attributes ... follow the XML Base ..."

Another sentence in sources that could use a s/id/uri/g:

  "Each SOURCE id and VERSION id is fetchable."

In the types section:

  "The 'uri' attribute is a URI ..."

Change to:

  "The 'uri' attribute is a URL ..."


Steve