When _. gets involved "all bets are off;" when _ or __ get involved betting, IMO, becomes a very tricky business; and when ... get involved,
X=. 5 [ Y=. 0 1$' ' plus=. + plus1=. plus"1 X (plus1 f. -: plus1) Y 0 J is, IMO, a wicked (in both senses of the word) programming language! > Behalf Of Randy MacDonald > > Henry; > > Thinking that Jsoftware's products will not undergo seemingly capricious > changes over time shows one's total lack of understanding of how Jsoftware > works. From the start, upward compatibility was a non-goal, in deference > to > doing the right thing, a concept more aesthetic than rigorous. > > > ----- Original Message ----- > From: "Henry Rich" <[EMAIL PROTECTED]> > To: "'Beta forum'" <[email protected]> > Sent: Thursday, July 06, 2006 12:24 AM > Subject: RE: [Jbeta] Incorrect result shape from 5 +"1 (0 1 $' ') > > > >I want my program to depend on J's following the rules. > > Most of the problems I have had come from boxed nulls rather > > than character, but the point is the same: if you don't follow > > the rules, how am I supposed to write working code? Do I have > > to check the result of every expression to see if you have > > decided to add 'knowledge' to the interpreter that changes > > a result? > > > > You seem to be arguing that if an expression is unusual > > enough I should be willing to accept whatever result you > > find convenient. It's as if you told me that > > 3.3428953286 + 2.645451867 was implemented to be 6.0 . > > It probably wouldn't hurt me, but I would think it > > arbitrary and unjustified. > > > > Changing the interpreter to follow the rules is fine; changing > > it to deviate from the rules is abominable. > > > > I don't think anything in the interpreter now causes spurious > > trading. I hope that condition persists. And if not - well, > > maybe the stock will go up. > > > > Henry Rich > > > >> -----Original Message----- > >> From: [EMAIL PROTECTED] > >> [mailto:[EMAIL PROTECTED] On Behalf Of R&S HUI > >> Sent: Wednesday, July 05, 2006 11:06 PM > >> To: Beta forum > >> Subject: Re: [Jbeta] Incorrect result shape from 5 +"1 (0 1 $' ') > >> > >> What you are arguing for is that > >> $ 5 +"1 (0 1$' ') should be 0 but that > >> $ 5 +"1 (0 1$0 ) should be 0 1 . > >> Is that really what you want your stock > >> trading program to depend on? > >> > >> > >> > >> ----- Original Message ----- > >> From: Henry Rich <[EMAIL PROTECTED]> > >> Date: Wednesday, July 5, 2006 7:55 pm > >> Subject: RE: [Jbeta] Incorrect result shape from 5 +"1 (0 1 $' ') > >> > >> > What I meant was, if I have defined > >> > > >> > plus =: + > >> > > >> > then +"1 and plus"1 should always get the same result. > >> > (That's why I wrote 'plus' rather than 'f'). > >> > > >> > The interpreter doesn't need to know that + and plus are > >> > the same. All it needs to do is follow the rule for > >> > empties, which requires checking the type, because the > >> > cell of fills is typed. > >> > > >> > I don't remember how I got into looking at 5+"1 (0 1$' ') > >> > but that isn't important. The practical difference to > >> > me between 0 1$0 and 0$0 is that > >> > (0 1$0) , 0$0 > >> > 0 > >> > (0 1$0) , 0 1$0 > >> > > >> > in other words, the wrong shape produces a list with > >> > one item when it should have 0 items. > >> > > >> > Maybe that won't matter - it might just be something > >> > on the screen a few seconds. Or, it might be a list > >> > of stock transactions to perform, in which case I will > >> > incorrectly commit 25% of my net worth to a bad stock. > >> > (This has actually happened. Last time the stock went > >> > up). > >> > > >> > So I really want rules to go by. Learning by experiment > >> > can be awfully expensive. > >> > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see > >> http://www.jsoftware.com/forums.htm > > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
