Thanks for your message. I know it has taken me a few days to respond, but
I have not been ignoring you. In fact I've spent several hours trying to
understand the issues with adverbs and conjunctions. It was only after a
careful re-reading, that I finally realized what you were telling me.

  foobar=. 1 : 0

 x -10

)

   4 foobar

_6

I don't believe I would ever have thought to try that without your message.
Now that I have, I believe the issue grows from Ken's initial Direct
Definition models. They only had two arguments:

⍺ and ⍵

The first J implementations I saw looked a lot like direct definition.

As manager of the SAX project, it was my job to decide which features we
could include. As a consequence, I had some lengthy arguments with Ken over
his current thinking about how to provide features I now see in J.
Interesting as those stories are to me, they don't belong in this forum.

Paul  (formerly:  [email protected])

On Fri, Aug 7, 2020, 9:10 AM Henry Rich <[email protected]> wrote:

> Is it a bug?  More a continuing penance for an initial faulty design.
>
> https://code.jsoftware.com/wiki/Vocabulary/com#Details note 11 describes
> the situation.
>
> In early J, the names u/v/m/n had not been invented, and an explicit
> modifier had only the names x and y to work with.  x was what we now
> call u, and y v.  Obviously, such a modifier was very restricted: to
> produce a modifier as we now know it, with access to u/v/x/y, the
> modifier would have to create the text after substituting its x/y, and
> have that reinterpreted by (3 : n) to create a verb.  That definition
> didn't last long, but while it was in force a few simple system
> modifiers were written, for example
>
>     bind
> 2 : 'x@(y"_)'
>
> Nowadays we would write 'u@m' or 'u@(m"_)'.  The language wasn't even
> weaned and it had a compatibility problem!
>
> The 'solution', still in place today, was to inspect the text of the
> modifier.  If no reference to u/v/m/n is found, the modifier is assumed
> to be old-style, and the names x and maybe y are defined as the modifier
> arguments.  With your example, an adverb has no y, so y is left
> undefined and you get a value error.  This error is detected when (1
> now) is executed.  You want a new-style modifier that defers execution
> until the (modifier+u/v) sees 'cat'.
>
> To get a new-style modifier, you have to have u/v/m/n in there
> somewhere.  Just as you discovered.
>
> Henry Rich
>
>
> On 8/7/2020 11:28 AM, Paul Jackson wrote:
> > This is not where I began. I had lots of use of the m argument, but all
> of
> > it in quotes. It took me a while to isolate the problem to something this
> > simple. Now that I have, I have also found other errors are signaled with
> > the dyadic case of an adverb, and both cases of a conjunction. As my
> second
> > example shows, I can avoid the problem with an unnecessary use of the
> name.
> > I can provide details if anyone has trouble replicating the rest of the
> > issues. What I'm hoping for is a confirmation that this is a bug.
> >
> > Paul
> >
> > now=: 1 : 0
> >   y
> > )
> >     1 now'cat'
> > |value error: now
> > |   y
> >
> > now=: 1 : 0
> >   y [m=. m
> > )
> >     1 now'cat'
> > cat
> >
> >     JVERSION
> > Engine: j901/j64/android
> > Release-f: commercial/2020-06-12T10:01:40
> > Library: 9.01.24
> > J Android: 1.4.09/9/28
> > Platform: Android 64 (arm64-v8a)
> > Installer: unknown
> > InstallPath:
> /storage/emulated/0/Android/data/com.jsoftware.j.android/files
> > Contact: www.jsoftware.com
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
>
>
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