--- Begin Message ---
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Subject: |
[PATCH] destructive splicing in backquote |
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Date: |
Fri, 06 Feb 2015 01:39:02 -0500 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) |
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>.
-- >8 --
Subject: [PATCH] destructive splicing in backquote
Allow Common Lisp-compatible destructive splicing in backquote
expressions using ",." syntax.
* lisp/emacs-lisp/backquote.el (backquote-destructive-splice-symbol):
New variable.
(backquote-process): Allow backquote-destructive-splice-symbol as a
synonym for backquote-splice-symbol.
---
lisp/ChangeLog | 7 +++++++
lisp/emacs-lisp/backquote.el | 6 +++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c18a8ff..fd643ed 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2015-02-06 Robin Templeton <address@hidden>
+
+ * emacs-lisp/backquote.el (backquote-destructive-splice-symbol):
+ New variable.
+ (backquote-process): Allow backquote-destructive-splice-symbol as
+ a synonym for backquote-splice-symbol.
+
2015-02-03 Artur Malabarba <address@hidden>
* emacs-lisp/package.el (package-delete): Document NOSAVE.
diff --git a/lisp/emacs-lisp/backquote.el b/lisp/emacs-lisp/backquote.el
index d5cdca2..b6e1792 100644
--- a/lisp/emacs-lisp/backquote.el
+++ b/lisp/emacs-lisp/backquote.el
@@ -90,6 +90,9 @@ For example (backquote-list* 'a 'b 'c) => (a b . c)"
(defconst backquote-splice-symbol '\,@
"Symbol used to represent a splice inside a backquote.")
+(defconst backquote-destructive-splice-symbol '\,.
+ "Symbol used to represent a destructive splice inside a backquote.")
+
(defmacro backquote (structure)
"Argument STRUCTURE describes a template to build.
@@ -160,7 +163,8 @@ LEVEL is only used internally and indicates the nesting
level:
(t (cons (if (eq (car-safe (nth 1 s)) 'quote) 0 1)
(nth 1 s))))
(backquote-delay-process s (1- level))))
- ((eq (car s) backquote-splice-symbol)
+ ((or (eq (car s) backquote-splice-symbol)
+ (eq (car s) backquote-destructive-splice-symbol))
(if (<= level 0)
(if (> (length s) 2)
;; (cons 2 `(append . ,(cdr s)))
--
2.1.4
--- End Message ---
--- Begin Message ---
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Subject: |
Re: bug#19790: [PATCH] destructive splicing in backquote |
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Date: |
Thu, 26 Sep 2019 18:38:09 +0200 |
Stefan Kangas <address@hidden> writes:
> Stefan Monnier <address@hidden> writes:
>
> > LGTM.
>
> Thanks. If there are no further comments, I'll commit the attached in
> a few days.
No more comments in 11 days, so I've now pushed this to master as
commit 3cf8f9b1ec. I'm consequently closing this bug.
Best regards,
Stefan Kangas
--- End Message ---