I am not sure I disagree with David, I am just arguing for consistency. Thanks!
Blake On Wed, May 28, 2014 at 5:02 AM, Juergen Sauermann < juergen.sauerm...@t-online.de> wrote: > Hi, > > I agree with David that this is counter-intuitive, but I will > make it IBM APL2 compatible. > > /// Jürgen > > > > On 05/27/2014 11:37 PM, David B. Lamkins wrote: > >> On Tue, 2014-05-27 at 15:19 -0500, Blake McBride wrote: >> >>> Dear David, >>> >>> >>> First, I assure you, this is how it works. >>> >> I'm certainly not arguing the fact that this is the behavior you've seen >> in other implementations. >> >> I'm simply trying to reconcile the behavior you describe in light of my >> long-ago experiences with APL 1 systems. If you take a look at the >> FinnAPL Idiom list (which predates APL 2), they describe the 0⍴<value> >> idiom for display suppression. >> >> What I'd really like to see is something in either the IBM Reference >> Manual or in the ISO Standard that support your assertion. I've been >> unable to find either support or refutation in those references. >> >> >>> I do know of a 0⍴<value> idiom for branching and for nullifying a >>> prior value in a subsequent assignment. I am unaware of any need for >>> that idiom to prevent printing. Can you give me one example in a >>> function? >>> >> Well, sure. This idiom is useful any time I'd like to evaluate a >> value-returning function for its side effect(s) without also printing >> the result of the function... >> >> >> >>> Thanks. >>> >>> >>> Blake >>> >>> >>> >>> >>> On Tue, May 27, 2014 at 2:32 PM, David B. Lamkins <dlamk...@gmail.com> >>> wrote: >>> I find this confusing and counterintuitive. >>> If displaying an empty vector causes the interpreter >>> to emit a >>> CR, what >>> then becomes of the 0⍴<value> idiom commonly used to suppress >>> display of >>> <value>? Wouldn't your output be littered with spurious CRs >>> every time >>> your program executed such a line? >>> I spent a half-hour digging through the IBM and ISO >>> references, finding >>> nothing on the subject of display of empty vectors. >>> On Tue, 2014-05-27 at 13:04 -0500, Blake McBride wrote: >>> > a. Neither an empty vector nor a vector of multiple >>> elements has a CR >>> > in it. The system prints the vector, and then prints a CR. >>> CR gets >>> > printed either way. >>> > >>> > >>> > b. I found all these errors while porting my production >>> code which >>> > ran consistently over IBM APL and several other APL's. They >>> all print >>> > a blank line. >>> > >>> > >>> > On Tue, May 27, 2014 at 12:57 PM, David B. Lamkins >>> <da...@lamkins.net> >>> > wrote: >>> > How is that so? '' is an empty vector. >>> > >>> > On Mon, 2014-05-26 at 20:30 -0500, Blake McBride >>> wrote: >>> > > ∇test >>> > > [1] '1' >>> > > [2] ' ' >>> > > [3] '2' >>> > > [4] '' >>> > > [5] '3' >>> > > [6] ∇ >>> > > test >>> > > 1 >>> > > >>> > > 2 >>> > > 3 >>> > > >>> > > >>> > > >>> > > >>> > > There should be a blank line between 2 and 3. >>> > > >>> > > >>> > > Thanks. >>> > > >>> > > >>> > > Blake >>> > > >>> > > >>> > >>> > >>> > >>> > >>> >>> >>> >> >> >> >
