Where angels fear to tread. Roger Costello's excellent XML Schema Tutorial includes a detailed breakdown of the ISBN. I've excerpted the documentation (along with Roger's GPL) here. The example also includes a complete ISBN schema, which involves a huge pile of regular expressions. The hyphens, which most book-related Web services ignore, are meant to carve up the address space in a very TCP/IP-like way: ... [Jon's Radio]
ISBN and IP numbers are very much NOT carved up in the same way. (We'll ignore the TCP red herring.) Breaking down IP numbers into subdivisions is completely arbitrary, excpeting of course any breakdown imposed by the next level up the hierarchy. There's nothing abouit a netmask that requires the set bits to be contiguous.
On the other hand ISBN does have an enforced structure. This fear:
The inventors of this scheme must have been chagrined to see Amazon and the rest of the book sites discard this carefully designed information architecture.
is unfounded, since nothing has been lost. The location of the hyphens is completely depends on the numbers used, so given the iSBN reduced to just digits the hyphens can easily be replaced.
9:54:32 PM  Categories: Pushing rectangles...
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