this is parsed as a token
   ;:'3e.4'
+----+
|3e.4|
+----+
but it (rightfully?) throws an error
   3e.4
|ill-formed number

this is also parsed as a token
   ;:'3j.4'
+----+
|3j.4|
+----+

the behavior seems endemic
   3p.4
4.74221
   3ad.4
2.99993j0.0209438
   3ar.4
2.76318j1.16826
   3x.4
4.47547
   3b.4
1.33333

I think either 3e.4 should be legal or all others should be illegal
for consistent.

Сб, 01 июл 2017, Martin Kreuzer написал(а):
> Looking at the examples, I came across the difference between
> 
>    3 j. 4      NB. spaces
> 3j4
> 
> and
> 
>    3j.4      NB. no spaces
> 3j0.4
> 
> Given that this (rightfully) throws an error
> 
>    .2 .3 .4 .5
> |syntax error
> |        .2 .3 .4 .5
> 
>  while this doesn't
> 
>    0.2 0.3 0.4 0.5
> 0.2 0.3 0.4 0.5
> 
> why then is the construct  3j.4 valid..?
> 
> -M
> 
> 
> At 2017-07-01 04:43, you wrote:
> 
> > > As Henry points out, the NuVoc page is quite a bit clearer on this topic.
> > 
> > Sample google search:
> >    site:jsoftware.com inurl:nuvoc complex
> > 
> > Quite a bit of reading there, if you have the patience for it (be sure
> > to mix in plenty of trial and error, though, or it's a total snoozer).
> > 
> > Thanks,
> > 
> > --
> > Raul
> > 
> > 
> > On Fri, Jun 30, 2017 at 11:30 PM, Rob Hodgkinson <[email protected]> wrote:
> > > Hi Lawrence, the “ill-formed number” is because "j." is a verb,
> > quite different to “j” which is part of a noun construct (like 3j4,
> > or 1e3 for 1000).
> > 
> > > So in your examples ...
> > 
> > > NB. But wait, not so fast:
> > >   1j.(2^0.5)%2
> > > |ill-formed number
> > > NB. No
> > 
> > > NB. Now try to separate the “j.” verb with a space either side to
> > make it clear to J that this is not “1jxxx” where J would assume you
> > are trying to make a complex constant.
> > >    1 j. (2^0.5)%2
> > > 1j0.707107
> > 
> > > The reason is that J can also directly interpret ‘complex
> > constants’ entered directly using the j notation (as a continuous
> > sequence of non-blank chars)…
> > >    3j4    NB. This is a single complex constant 3+i4
> > > 3j4
> > 
> > >    3 j4    NB. But now J tries to view this as a list of (3) and (j4)
> > which which J would assume is (3) and a variable called (j4).
> > > |syntax error
> > > | 3 j4
> > 
> > > As Henry points out, the NuVoc page is quite a bit clearer on this topic.
> > 
> > > HTH, Regards Rob
> > 
> > 
> > >> On 1 Jul 2017, at 1:14 pm, Lawrence Wickert <[email protected]>
> > wrote:
> > >>
> > >> Hello,  I am a old EE still trying to learn.  I am a real beginner
> > having no end of problems with specifying complex numbers.  I am using
> > j64-804 on ubuntu 12.04.  I am either doing something really stupid or I
> > need to update to 806.  Updating anything gives me heartburn or worse so
> > I hope it is just my misunderstanding of basic principles. Although I
> > have a bad habit of RTFM as a last resort I have tried the Dictionary to
> > no avail.  I appreciate any guidance.
> > >>
> > >>   0j(2^0.5)%2
> > >> |ill-formed number
> > >>
> > >>   0j((2^0.5)%2)
> > >> |ill-formed number
> > >>
> > >>   j.(2^0.5)%2
> > >> 0j0.707107
> > >> NB. Eureaka, OK, I get it!
> > >>
> > >> NB. But wait, not so fast:
> > >>   1j.(2^0.5)%2
> > >> |ill-formed number
> > >> NB. No
> > >>
> > >>   1j(2^0.5)%2
> > >> |ill-formed number
> > >> NB. Still No
> > >>
> > >>   1+j.(2^0.5)%2
> > >> 1j0.707107
> > >> NB. This works!
> > >>
> > >> Let's try to do something with it:
> > >>   k=:(0 1+j.(2^0.5)%2 3 4 0 5)
> > >> |length error
> > >> |   k=:(0 1    +j.(2^0.5)%2 3 4 0 5)
> > >>
> > >> NB. Maybe parantheses will help:
> > >>   k=:(0 (1+j.(2^0.5)%2) 3 4 0 5)
> > >> |syntax error
> > >> |   k=:(    0(1+j.(2^0.5)%2)3 4 0 5)
> > >>
> > >> NB. This one has to work:
> > >>   k=:(0 1j0.7071 3 4 0 5)
> > >>   k
> > >> 0 1j0.7071 3 4 0 5
> > >> NB. It does but it can't be the only way to do it.
> > >>
> > >> NB. One last rry:
> > >>   g=: 1+j.(2^0.5)%2
> > >>   g
> > >> 1j0.707107
> > >> NB. That's nice.
> > >>
> > >>   k=:(0 g 3 4 0 5)
> > >> |syntax error
> > >> |   k=:(    0 g 3 4 0 5)
> > >> NB. This isn't nice.
> > >>
> > >> Lost in the high desert of New Mexico, Larry Wickert
> > >>
> > >> ----------------------------------------------------------------------
> > >> 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

-- 
regards,
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