> 4. CAN X ONLY IF Y: Equivalent to "CANNOT X UNLESS Y". Similar > for (MUST, MAY, SHALL, SHOULD) X ONLY IF Y.
> I'm not sure I follow this. I see this as the definition of ONLY IF. > > So, ONLY IF is only defined in the context of CAN X ONLY IF Y. > > So, the intent here is to also make this the definition of UNLESS also. > > Have I missed or misunderstood something? The proposed version would define ONLY IF in terms of UNLESS. UNLESS is defined nowhere in the ruleset; conversely, the decapitalized unless in the current rules is defined by R754(3). In other words, the proposed version *relies on* the definition of UNLESS, but does not in itself *constitute* a definition of UNLESS. If you wish to provide a definition of UNLESS, I suggest something along the lines of "CAN X UNLESS Y means: CANNOT X IF Y, and CAN X otherwise." Which brings up an interesting point: should MMI have definitions for words like AND, OTHERWISE, etc? Or is R754(3) sufficient to import the boolean-logical senses? (I think it's sufficient.) [We really should canonize CAN NOT as a synonym of CANNOT, though.]
