It not just an empty array but an empty produced by the catenation of two empties. This does not seem like a firm foundation to build code on.
----- Original Message ----- From: Henry Rich <[EMAIL PROTECTED]> Date: Thursday, October 19, 2006 7:59 am Subject: RE: [Jprogramming] data type of empty , empty > > Why does it matter to you? > > Because an empty list of boxes is different from an > empty list of numbers, and code can work or not work > depending on which result is produced by , . > > Also, the behavior as described below violates the > principle of J that the user doesn't need to concern > himself with the type of numbers. As implemented, a > complex list produces numbers, while an integer > list produces boxes. > > It is very important that empties be handled consistently, > and not just by pretending that the type doesn't matter, > so that code doen't have to check for empty operands. > > Henry Rich > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [EMAIL PROTECTED] On Behalf Of Roger Hui > > Sent: Thursday, October 19, 2006 9:15 AM > > To: Programming forum > > Subject: Re: [Jprogramming] data type of empty , empty > > > > > > > > > > ----- Original Message ----- > > From: bill lam <[EMAIL PROTECTED]> > > Date: Wednesday, October 18, 2006 6:56 pm > > Subject: [Jprogramming] data type of empty , empty > > > > > I tested appending empty to empty of different data types. > > > (3!:0) (0$0) , 0$0 > > > 1 > > > (3!:0) (0$0) , 0$' ' > > > 2 > > > (3!:0) (0$2) , 0$' ' > > > 4 > > > (3!:0) (0$2.2) , 0$' ' > > > 8 > > > (3!:0) (0$u:'a') ,~ 0$a: > > > 131072 > > > (3!:0) (0$u:'a') , 0$a: > > > 131072 > > > (3!:0) (0$' ') ,~ 0$a: > > > 32 > > > (3!:0) (0$1r3) , 0$a: > > > 128 > > > (3!:0) (0$0) , 0$a: > > > 32 > > > (3!:0) (0$2) , 0$a: > > > 32 > > > (3!:0) (0$2.2) , 0$a: > > > 8 > > > (3!:0) (0$1j2) , 0$a: > > > 16 > > > > > > At first, I thought data type is the larger of 3!:0, but a > counter > > > example in > > > the last line. It also seems data type does not depend on > leftmost > > > or rightmost > > > position. Does anyone know the rule of deriving the data type? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
