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
