When would you ever say f"f ?
----- Original Message ----- From: Zsbán Ambrus <[email protected]> Date: Wednesday, November 10, 2010 7:06 Subject: Re: [Jprogramming] Atop u...@v with v of negative monadic rank To: Programming forum <[email protected]> > On Wed, Nov 10, 2010 at 3:15 PM, Roger Hui <[email protected]> wrote: > > The change you propose is non-trivial and has consequences > > that may surprise you (and many others, I expect). > > > > Suppose f is <"_1, and you make the "combining rank" of > > f be _1 instead of the current _ . > > > > So the ranks of ]...@f would be _1 (_1 _1 _1). Suppose the > > argument x is i.2 3 4. Since the ranks of ]...@f are _1, > > x is split into the cells i.3 4 and 12+i.3 4 and you apply > > ]...@f to each cell. [...] > > You're right in that combining ranks shouldn't have negative integers, > because that too would make (f"f) mean something different from f, > such as in the case when (f=:<"_1). I accept that that > change would > be a bad idea, so I retract that part of my suggestion. > > On the other hand, are there many surprises or incompatibilities even > if you take only the weaker variant of my proposal? That > says that if > rl is a negative integer and rr is a nonnegative integer, the diadic > combining rank of f"(rl,rr) should be (_ _) instead of > (_,rr). For > example, the combining rank of (]"_ _3 7) would be (_ _ > _). The case > with left and right swapped would be handled similarly. > The combining > ranks would still always be nonnegative. > > As I said, this too would be better than the current state > because it > would help uphold the f -: f"f identity, which the current semantics > does not do for such verbs. > > Ambrus ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
