I am not entirely sure what you are trying to convey either. Apparently,
you are implying that "F=: FB^:FT^:_" would be, in some sense, simpler than
the original F but that might not be necessarily the case (depending on the
nature of FB and FT; which you did not specify).
Your claim, to me (so far), is not much different than, for example,
If I have a recursive verb (F y) implemented in J, which satisfies the
constraints for tail recursion, I believe that there is always a pair
of companion functions (FB y) (FT y) such that an F workalike can be
written:
F=: FB@:FT y
(So what?)
On Mon, Jan 8, 2018 at 7:45 PM, Raul Miller <[email protected]> wrote:
> I'm not entirely sure what issue you are trying to raise here, so I will
> guess:
>
> In languages which support tail recursive optimizations for recursive
> functions, those optimizations can still be deployed if the function
> in question contains an expression which uses some different recursive
> function. Why should J's induction be any different?
>
> Thanks,
>
> --
> Raul
>
>
>
> On Mon, Jan 8, 2018 at 7:08 PM, Jose Mario Quintana
> <[email protected]> wrote:
> > The claim [2], as written, does not impose any restrictions on FN or FT
> > apart from being monadic; thus, F itself could be embedded in FB and
> could
> > provide an opportunity to cheat and defeat its purpose.
> >
> > Surely you mean something more substantial. Can you elaborate your
> claim?
> >
> >
> > On Wed, Jan 3, 2018 at 8:09 AM, Raul Miller <[email protected]>
> wrote:
> >
> >> [1]
> >>
> >> If I have a tail recursive function F, which calls function G, there
> >> is normally no problem with G signaling that F needs to exit. Just
> >> return a distinguished value from G and in F have an if statement
> >> which returns when that happens. Since F is tail recursive, nothing
> >> more needs done.
> >>
> >> So I would like to see an example of how this description:
> >>
> >> >> I have a deeply embedded function that discovers that it has
> completed
> >> the
> >> >> task set before it. ...
> >> >>
> >> >> This function was not part of the initial design.
> >>
> >> has anything to do with tail recursion.
> >>
> >> [2]
> >>
> >> If I have a recursive verb (F y) implemented in J, which satisfies the
> >> constraints for tail recursion, I believe that there is always a pair
> >> of companion functions (FB y) (FT y) such that an F workalike can be
> >> written:
> >>
> >> F=: FB^:FT^:_ y
> >>
> >> which satisfies the "bounded stack usage" guarantee of tail recursion.
> >> And this form has an additional advantage, which is that a rewrite
> >> which removes the bounded stack character requires work on the part of
> >> the developer which is quite significant - it's unlikely that you will
> >> have someone making such changes without realizing that they are doing
> >> so.
> >>
> >> But I would be interested in seeing a counter-example that destroys my
> >> belief, if counter examples exist.
> >>
> >> Thanks,
> >>
> >> --
> >> Raul
> >>
> >>
> >> On Wed, Jan 3, 2018 at 5:44 AM, Erling Hellenäs
> >> <[email protected]> wrote:
> >> > Try to remove all references to persons from your postings.
> >> >
> >> > I don't think my post is in any way strange. According to my
> judgement no
> >> > further explanation is needed.
> >> >
> >> > /Erling
> >> >
> >> >
> >> > Den 2018-01-02 kl. 13:18, skrev Raul Miller:
> >> >>
> >> >> If you would answer those two questions we could do that.
> >> >>
> >> >> Thanks,
> >> >>
> >> >
> >> > ------------------------------------------------------------
> ----------
> >> > 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
>
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