Roy, On 2012-05-02 20:32, Roy T. Fielding wrote: > On May 2, 2012, at 10:48 AM, Murray S. Kucherawy wrote: >> 2) There's a common axiom that says it's safer to refer to a definition >> rather than to copy it. > > I think we should recognize that as a false axiom and move on. > > We should refer to orthogonal definitions that are subject to > independent change control -- e.g., protocol elements that are > defined in another spec because they change at a different > rate than the referring spec or are used by multiple specs. > > We should copy a definition by value if the referring spec > depends on the definition (does not allow the parser to change > even if some other spec were to define it and later extend it).
But that is contrary to the general principle in the IETF of using normative references and *not* replicating normative material, to avoid mistakes. Both approaches have their advantages and disadvantages, but making ABNF an exception seems problematic, or at least a decision that can't be taken at Area level. > My preference is to not use prose definitions at all -- I used > them as a crutch when I first started writing IETF specs in 1994, > and they burned me every time. > > And if we go down the slippery slope, I would love to have a > formal definition of set reduction, as in > > ALPHA = ALPHANUM - DIGIT > > since I very commonly need rules that only differ by one or two > characters being removed from the allowed set. Would you call that "disinheritance" ? Brian _______________________________________________ websec mailing list websec@ietf.org https://www.ietf.org/mailman/listinfo/websec