"named verb" is a concept relevant to an expression of the form: name~
However <@name has no rank properties different from <@verb in the general case. Note also that verbs with an empty domain still have rank. [:"2 for example... Is this useful? Perhaps not directly, but one of the things J's design does is help train the user to be aware of the empty spaces between concepts (or however you want to call it - see also: empty array jokes), or the flavors of nothing. J is a tool of thought and that, in my opinion at least, is just awesome. Thanks, -- Raul On Thu, Jul 25, 2013 at 5:38 PM, <[email protected]> wrote: > I learned something new in the last 90 minutes, this is a small > summary. > > (I always tell people that one never stops learning J. Nevertheless > I'm still always a bit surprised when this holds for me, too. :-) > > It dawns on me that I just re-answered the "when is v f. not v?" FAQ > which I admittedly always skipped so far. > > > Roger Hui wrote: >> a. The dictionary entry for m~ should not say that its rank is _ . > > I always felt that _ (or rather: _ _ _) was quite an appropriate choice > for the rank of m~ verbs. My reasoning: the entire purpose of this > construct is dynamic/deferred name evaluation, and _ _ _ is the best > a priori rank fixing which is meaningful here. > >> The ranks should be mv lv rv, which are the ranks of the named verb. > > My first reaction on this was "No way!" Becase, what does that mean for: > > foo = +: > v =. 'foo'~ > v b. 0 NB. now according to the suggested mv lv rv ruling: > 0 0 0 > foo =. |. > v b. 0 > ? ? ? > > My question being how much we want to mess with the "intrinsic" rank > of a verb. > > However, before I haggle about the m~ rank, I should probably > first try decide for myself how "intrinsic" or "sticky" I want > to settle the following, a bit more essential question: > > Tests with J4/6/7 all show this behaviour: > > foo =. +: > v =. <@foo > v b. 0 > 0 0 0 > v i. 3 > +-+-+-+ > |0|2|4| > +-+-+-+ > > NB. So far, so good, nothing special here. > NB. Now let us redfine foo and see what happens: > > foo =. < > v b. 0 > 0 0 0 > v i. 3 > +---+---+---+ > |+-+|+-+|+-+| > ||0|||1|||2|| > |+-+|+-+|+-+| > +---+---+---+ > v > <@foo > > Oh. I'm probably the last one to notice this. Let's call this > behaviour > > "Named verbs have sticky rank." > > While I can understand this actual behaviour, I am not sure whether > I should like it. I certainly don't like that this experiment can > be continued with: > > v f. 1 2 3 NB. *not* the same as v 1 2 3: > +-------+ > |+-----+| > ||1 2 3|| > |+-----+| > +-------+ > > Then again: fixing 'm'~ at rank mv ml mr early on is just consistent > with v having sticky rank. > > Question to everybody: > > If I were to re-implement J and would "auto-correct"/"recompile" > derived definitions, would you... > > [ ] like it > [ ] hate it because it's changing past behaviour > [ ] consider it conforming to the Dictionary > [ ] cry foul because you think The Dictionary mandates "sticky rank" > [ ] don't give a damn either way > > Martin > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
