[RESEND] Media types for RDF languages N3 and Turtle

Garret Wilson garret at globalmentor.com
Fri Dec 21 15:54:53 CET 2007

Graham Klyne wrote:
> (1) use application/(something) rather than text/(something) in *all* cases
> where the content is not primarily for human consumption - i.e. if you expect to
> do anything other than display as-is on a character display.

I think the last part of that sentence is definitely too far---the only 
thing that would be displayed "as-is on a character display" is 
text/plain. Besides plain text, "primarily for human consumption" is one 
possible criterion, but is that the most useful criterion? RFC 2046 
mentions, "The 'text' media type is intended for sending material which 
is principally textual in form." I don't know what that means exactly, 
but the RFC goes on to say things in this category are "to some extent 
readable" and that, "It is useful, then, to distinguish them, at the 
highest level, from such unreadable data as images, audio, or text 
represented in an unreadable form."

I don't have a strong opinion here, but I will point out that RFC 2046 
talks about the category being "the highest level" division and that it 
is "useful". To me, it is useful at a high level to note that the 
content types discussed here have the following characteristics:

* The content bytes are interpreted as text characters (i.e. Unicode 
code points); ignoring encoding, no bytes are interpreted as anything 
other than text characters. (These text characters may later be subject 
to some meta-interpretation---e.g. delimiters---but they are first 
interpreted as text characters.)

* These content types can always be edited in a text editor.

* Abstract values, such as numbers, are represented by their text 
lexical forms, not by some non-text encoding.

To me those points are meaningful, and it might be useful to include 
those criteria when making a high-level distinction.

Is the top-level type of RFC 2046 even useful anymore? I think the 
biggest criteria for me is, "can I edit this thing in a text editor?" 
Whether the author meant the information to be directly displayed to the 
user, while interesting, seems less useful from a content-processing 
point of view.


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