[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Notations and MIME types
I will try to explain the issues in a way that both sides will find intelligible. There seem to be the following conceptual differences between notations and MIME types: 1. Notation names are normally declared locally, whereas MIME type names have a global registry with a provision for local-use extensions. This is resolved by noting that the NOTATION declaration provides for a public ID and an URL (system id). The system id of a notation corresponding to a MIME type can refer to the URL where the definition (in English) of the MIME type is stored. A group of public IDs could also be manufactured of the type "-//IETF//NOTATION MIME text/plain//EN", which would be understood to be equivalent to the MIME type "text/plain". 2. Syntactically, MIME-types employ characters that aren't allowed in public IDs or in XML Names. This could be resolved by a mapping convention. The most important character in this respect is "/", which is allowed in public ids but not in Names, since every MIME type name has exactly one "/". 3. There is a difference in expectation between the SGML style and the Internet/MIME style about who declares what. SGML systems expect that referring documents will know the notation used by objects that they refer to. Internet documents such as mail messages or Web pages, OTOH, usually simply refer to external documents by URL, and expect either that the MIME type can be guessed from the URL, or else that the remote system will return the MIME type along with the content. I don't know just what should be done to smooth over this difference. I hope this helps to clarify the issues. -- John Cowan http://www.ccil.org/~cowan cowan@c... You tollerday donsk? N. You tolkatiff scowegian? Nn. You spigotty anglease? Nnn. You phonio saxo? Nnnn. Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5) xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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