bug#19790: [PATCH] destructive splicing in backquote

[Lars Ingebrigtsen]

Robin Templeton <robin@terpri.org> writes:

> Common Lisp and MACLISP define comma-dot syntax for destructive splicing
> in backquote expressions. The Elisp reader reads ",.x" as "(\,\. x)"
> (like ",@"), but the resulting forms are not processed by the backquote
> library. A patch follows that adds CL-compatible comma-dot support.
>
> Originally reported by at Artur Malabarba in
> <http://lists.gnu.org/archive/html/emacs-devel/2015-01/msg00624.html>.

I think the conclusion to the discussion was that we do not want to
support the ,. operation in Emacs Lisp.

(setq .foo 1)

`((,.foo))
=> (((\,\. foo)))

So we should remove this feature completely, because that's obviously a
bug...

-- 
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   bloggy blog: http://lars.ingebrigtsen.no