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

[Lars Ingebrigtsen]

Augusto Stoffel <arstoffel@gmail.com> writes:

> +(defmacro thread-as (var &rest forms)
> +  "Successively bind VAR to the result of evaluating each of the FORMS.
> +Return the last computed value.
> +
> +Example:
> +     (thread-as x
> +       4
> +       (- 10 x)
> +       (/ x 2))
> +          ⇒ 3"
> +  (declare (indent 1))

I'm not enthusiastic.  As experience with the other threading macros has
shown, they're neat hacks, but they're not used much in actual code
(because there's no culture for reading code that's formatted that way
in Emacs Lisp).

If others think that this would be useful, I won't object to adding it,
though.  Eli, what do you think?