Re: locating schemas via public ids

[Paul Grosso <pgrosso@arbortext.com>]

At 10:16 2001 01 24 -0500, Norman Walsh wrote:
>/ Paul Grosso <pgrosso@arbortext.com> was heard to say:
>| [7] Not to presume to constrain a solution to the problem, but
>|     even something such as the following might be acceptable:
>|     Say that each member--that is currently a URI--is optionally
>|     delimited by quotes and consists of either a SystemLiteral
>|     (production 11 in XML 1.0) OR the second half of the
>|     disjunction in production 75, to wit:
>|       'PUBLIC' S PubidLiteral S SystemLiteral
>|     (which, since it contains spaces, would necessarily be quoted).
>
>I'm not sure this is sufficient, unless you mean to assert that
>if-and-only-if it's quoted, it's to be assumed to be a public
>identifier. I think there needs to be some way to distinguish public
>identifiers from system identifiers in the schema hints list.

No, not that.  I think it works.  Members are separated by spaces.
Each member is one of the following:

1.  if the first character is not a quote, take up to the next space
    and treat that string as a URI giving the system id.  This is
    what is currently the case.

2.  if the first character is a quote, take up to the next matching
    quote.  strip the surrounding quotes and non-embedded spaces and
    consider the remaining string.  
  a.  if it starts with PUBLIC (in any case) followed by a space,
      parse it like you would the second half of XML's production 75,
      giving you both a public id and a system id.
  b.  else, it must be a URI giving the system id.

However, as I said just a bit earlier, what with having all this
in a attribute value requires three levels of quotes, and this
is a bit much, so I'm tempted just to delete this note in our 
message.  But the point is that we need some way for schemaLocation
to specify both a public id and a system id, just like the doctype
decl of XML can do for a DTD.

paul