Right. So I see I've not used J for far too long.
It's indeed only ever used directly, i.e. not in derived verbs.

Thanks Henri!

Op za 9 mrt. 2019 om 17:34 schreef Henry Rich <[email protected]>:

> Reassigning N affects later execution of mod but not verbs created
> previously by mod:
>
> mod =: 1 : 'N&|@:x'
>     N =: 5
>
>     mod5double =: +: mod
>
>     mod5double 4
>
> 3
>
>     N =: 7
>
>     mod5double 4
>
> 3
>
>     mod7double =: +: mod
>
>     mod5double 4
>
> 3
>
>     mod7double 4
>
> 1
>
>
> Henry Rich
>
>
>
> On 3/9/2019 10:32 AM, Jan-Pieter Jacobs wrote:
> > Hi!
> >
> > There's a fairly substantial problem with chapter 32 of FSOJ, as it uses
> > this definition for mod:
> >
> > mod=: adverb : 'n&|@x'
> >
> >
> > Aside the fact that using it as defined yields a domain error (easily
> > solved using N instead of n), there is a problem where afterwards the
> > article seems to assume that reassigning n (or N) influences mod.
> >
> > However, it does not (at least in recent J), and would need redefining
> mod
> > every time a different N is used.
> >
> >
> > Would replacing mod by the following definition be acceptable:
> >
> > mod =: 2 : 'n&|@u' ? It is then used as (^ mod 10) for modulo 10
> > exponentiation, for instance.
> >
> >
> > What do you think?
> >
> > Best regards,
> >
> >
> > Jan-Pieter
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
>
>
>
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