bug#56875: 29.0.50; [PATCH] Add thread-as macro

[Augusto Stoffel <arstoffel@gmail.com>]

On Tue,  2 Aug 2022 at 23:47, Richard Stallman <rms@gnu.org> wrote:

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>
>  > +     (thread-as x
>  > +       4
>  > +       (- 10 x)
>  > +       (/ x 2))
>
> I propose a different syntax which is more Lispy than thread-as, and
> more self-evident:
>
> (let-successive ((x 4
>                     (- 10 x)))
>   (/ x 2))
>
> A Lisper can guess what it means, without having read a description.
>
> It lends itself to a generalization where there is more than
> one bound variable, each of which can have several values:
>
> (let-successive ((x 4
>                     (- 10 x))
>                  (y 6
>                     (- 12 y)))
>   (* x y))
>  => 36
>
> The values after the first can refer to all of the variables,
> since all of them are already bound (to the previous values)
> at that point.

This is an interesting alternative.  I'd suggest to wait for other
opinions about the need for this kind of macro in general, and which
variant is preferred.