Kirk posted:
<<<>>
2/ I would suggest that any numeric constant which include a 'j' or 'a'
should return complex precision.
(Except for 'b' constants such as 16ba, of course).

Eg:
1j0
1ar0
1ad0
<<<<>>>>
NB. I agree with Kirk!

NB. some interesting results:

datatype each 3j6 3ar6 3ad6 1j0

│complex│complex│complex│complex│


datatype 1j0

integer

datatype each 3j0 3ar0 3ad0 1j0

│integer│integer│integer│integer│

NB. Not good


NB, However:

datatype each 3j0 3j1 3ar0 3ar1 3ad0 3ad1 1j0 1j1

│complex│complex│complex│complex│complex│complex│complex│complex│



Skip Cave
Cave Consulting LLC


On Sat, Nov 23, 2019 at 11:29 AM Kirk Iverson <[email protected]>
wrote:

> 2/ I would suggest that any numeric constant which include a 'j' or 'a'
> should return complex precision.
> (Except for 'b' constants such as 16ba, of course).
>
> Eg:
> 1j0
> 1ar0
> 1ad0
>
> And that the representation of a verb such as  (1j1-0j1)&+  be
> 1j0&+
>
>
> 4/ I also noticed the following, but don't really have a position on
> whether it's correct or not:
>    datatype 01
> integer
>    datatype 0".'01'
> boolean
>
>
> 5/ As an aside, could anyone have predicted the following?
>    16ba0
> 160
>    2j160
> 2j160
>    2j16ba0
> 20j160
>
> Of course anyone using 'j' and 'b' together deserves what they get. :)
>
>
> /K
>
>
>
> On Fri, Nov 22, 2019 at 3:20 AM Henry Rich <[email protected]> wrote:
>
> > 1/ Because the decoration comes before the value, it was easier to put
> > the 0 at the beginning of the display.  That's a weak argument, but
> > that's why I did it that way.
> >
> > 2/ I was just thinking about this last night.  You're right, for
> > consistency complex values should be decorated.  But the point of the
> > decoration is to have a linear form that faithfully reproduces the
> > value.  1j0 does not produce a complex value.  Before the decoration, we
> > need to agree on a way to write a constant that produces a complex
> > precision with imaginary part 0.
> >
> > 3/ I defer to Bill on this.
> >
> > Henry Rich
> >
> > On 11/22/2019 1:04 AM, Kirk Iverson wrote:
> > > A recent thread in the programming forum (00 strange?) inspired me to
> > look at this new behaviour in 901.
> > >
> > >     NB. Numeric
> > >     datatype&.> 'b i f x c'=. 0 1;(0 1+0);(0 1%1);0 1x;0,1j1-0j1
> > > +-------+-------+--------+--------+-------+
> > > |boolean|integer|floating|extended|complex|
> > > +-------+-------+--------+--------+-------+
> > >     b&+
> > > 0 1&+
> > >     i&+
> > > 00 1&+           <== (1)
> > >     f&+
> > > 0 1.&+
> > >     x&+
> > > 0 1x&+
> > >     c&+
> > > 0 1&+            <== (2)
> > >
> > >
> > >     NB. Character
> > >     d=. (0{a.);'abc'
> > >     'lctrl lascii'=. d
> > >     'uctrl uascii'=. u:&.> d
> > >     'Uctrl Uascii'=. 10 u:&.> d
> > >     datatype&.>lctrl;lascii;uctrl;uascii;Uctrl;Uascii
> > > +-------+-------+-------+-------+--------+--------+
> > > |literal|literal|unicode|unicode|unicode4|unicode4|
> > > +-------+-------+-------+-------+--------+--------+
> > >     lctrl&,
> > > (00{a.)&,
> > >     lascii&,
> > > 'abc'&,
> > >     uctrl&,
> > > (u: 00)&,
> > >     uascii&,
> > > (u: 97 98 99)&,        <== (3)
> > >     Uctrl&,
> > > (10&u: 00)&,
> > >     Uascii&,
> > > (10&u: 97 98 99)&,     <== (3)
> > >
> > >
> > > 1/ Is there a reason that it is the first element of an integer array
> > which has extra decoration, rather than the last element (as in the other
> > cases)?
> > >
> > > 2/ Shouldn't this display as  0 1j0&+   ?
> > > Also, when interpreting constants in a line of J:
> > > 0 1    is boolean
> > > 00 1   is integer
> > > 0 1.   is floating
> > > 0 1x   is extended (as is  0 1r1)
> > > 0 1j0  is integer
> > > Shouldn't this last one be complex?
> > >
> > > 3/ Can the representations of uascii and Uascii make use of literals
> > (like lascii does)?
> > >
> > > /K
> > > ----------------------------------------------------------------------
> > > 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
>
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