No, I mean that {iota}0 depends on {quad}io, which
is what said.
a: is what used to be denoted {jot} in "Practical
Uses of a Model of APL" from APL82 (and
subsequently "Rationalized APL" and "A Dictionary
of APL"). This reinterpretation of {jot} was
invented by Arthur Whitney in 1981. To my knowledge
it predates any use of zilde in APL.
----- Original Message -----
From: ramacd <[EMAIL PROTECTED]>
Date: Friday, March 16, 2007 12:43 pm
Subject: Re: [Jgeneral] definition of a:
> Hi Roger;
>
> Okay... you mean it fails if []io is undefined. I'd say that
> 'depends on the
> existence of X' and 'depends on the value of X' are distinct
> enough not to
> be coverable by 'depends on X' I'm also young enough to barely
> remember IO
> IMPLICIT ERROR's. I also got used to using the zilde (0 overstrike
> ~) which
> probably was what generated the idea of a: in the first place, but
> I wasn't
> on that plane ride.
> ----- Original Message -----
> From: "Roger Hui" <[EMAIL PROTECTED]>
> To: "General forum" <[email protected]>
> Sent: Friday, March 16, 2007 4:31 PM
> Subject: Re: [Jgeneral] definition of a:
>
>
> > Execute foo in your APL where
> >
> > {del} z {is} foo ; {quadio}
> > z {is} {iota} 0
> > {del}
> >
> >
> >
> > ----- Original Message -----
> > From: ramacd <[EMAIL PROTECTED]>
> > Date: Friday, March 16, 2007 12:19 pm
> > Subject: Re: [Jgeneral] definition of a:
> >
> > > Hi Roger;
> > >
> > > Ok, I'm stumped: how does {iota}0 depend on {quad}io?
> > >
> > > >: ...
> >
> >
> >
> > > ----- Original Message -----
> > > From: "Roger Hui" <[EMAIL PROTECTED]>
> > > To: "General forum" <[email protected]>
> > > Sent: Friday, March 16, 2007 12:49 PM
> > > Subject: Re: [Jgeneral] definition of a:
> > >
> > >
> > > > I started using {rho}0 to denote the empty list
> > > > in APL because (a) it is shorter than 0{rho}0
> > > > (b) it does not depend on {quad}io like {iota}0
> > > > does (c) it has right "type" where '' does not.
> > > > >From APL to J {rho}0 got changed to $0.
> > > >
> > > > Of course strictly speaking it should be "an empty
> > > > list" rather than "the empty list". But the
> > > > differences between the various empty lists are
> > > > more amusing than significant. When I was a mere
> > > > pup I used to pester and annoy the APL implementers
> > > > with questions like: What is the difference
> > > > between ({iota}0),'' and '',({iota}0) and why?
> > > > I guess payback exists after all.
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: [EMAIL PROTECTED]
> > > > Date: Wednesday, March 14, 2007 1:56 pm
> > > > Subject: Re: [Jgeneral] definition of a:
> > > >
> > > > > The" weather" comment is funny but as I said: "I am from a
> > > > > different
> > > > > cultural background" so making fun of my mistakes in English
> > > is
> > > > > fine with
> > > > > me,since I have a good sense of humor.
> > > > >
> > > > > The empty list is exactly what I wanted (refer to the early
> > > > > discussions of
> > > > > <i.0
> > > > >
> > > > > The question was, as everyone can read from my earlier post:
> > > > > Roger ! any enlightening comment ?
> > -----------------------------------------------------------------
> -----
> > For information about J forums see
> http://www.jsoftware.com/forums.htm
> -------------------------------------------------------------------
> ---
> For information about J forums see http://www.jsoftware.com/forums.htm
>
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