On Fri, 13 Mar 2009, comex wrote: > On Fri, Mar 13, 2009 at 3:43 PM, Kerim Aydin <ke...@u.washington.edu> wrote: >> On Fri, 13 Mar 2009, comex wrote: >>> The special case of a simple 'X SHALL do Y by >>> <mechanism> was established in CFJs 1765 and 1890 to imply the >>> mechanism, but I'd argue that's just an archaic linguistic shortcut, >>> not a necessary side-effect of the SHALL. >> >> Sorry, you're right; but the CFJ statement is indeed for cases where >> it's "X SHALL do Y by mechanism Z"; so as long as we're assuming that the >> archaic shortcut is functional, it's relevant. -G. > > But I argue it's _just_ a linguistic shortcut: not some odd attribute > of 'CAN-ness' attached to the obligation, but an expansion to apply > within the rule's text before anything else is considered. > > 'SHALL by announcement' --> 'CAN by announcement, and SHALL' > > 'SHALL NOT by announcement' --> well, I guess this has never been > tested. Is it 'CAN by announcement, but SHALL NOT' or just 'SHALL NOT > use the announcement mechanism to ...'? > > Either way the answer is TRUE because one or both rules say CAN and > neither say CANNOT.
That's reasonable. But you do leave out the third possibility for 'SHALL NOT by announcement', which is 'CANNOT by announcement and SHALL NOT'. Not that it's a particularly likely construction, I agree, but its unlikeliness is as much a historical accident as the original shortcut. -G.