Error in nested backquoting

Error in nested backquoting

[Diego Sevilla Ruiz]

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Dear all:

	I think I spotted an error in backquote.el answering this question in 
stackoverflow:

http://stackoverflow.com/questions/17394638/nesting-backquote-and-in-emacs-lisp

	In backquote expansion, the symbol for backquote (`) is treated specially 
for nested backquoting, but its alias, backquote (if it is intended for it 
to be used from elisp programs) is not correctly evaluated in nesting. The 
patch (I think) is straightforward, and I include it as an attachment, but 
you experts out there have to judge.

	I would like to contribute it myself, but at the moment I'm not sure of 
the steps I have to follow to do so (sign agreement? obtain write access to 
repo?).

	Best regards,
	diego.

-- 
Diego Sevilla Ruiz -- http://ditec.um.es/~dsevilla/ -- dsevilla@um.es _.___
Dep. Ingeniería y Tecnología de Computadores, Facultad de Informática D|TEC
Univ.de Murcia,Campus Espinardo,30080 Murcia (SPAIN),Tel.+34868887571

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--- backquote-old.el	2013-07-01 00:36:28.319352290 +0200
+++ backquote.el	2013-07-01 00:37:51.550816668 +0200
@@ -161,6 +161,8 @@
       (backquote-delay-process s (1- level))))
    ((eq (car s) backquote-backquote-symbol)
       (backquote-delay-process s (1+ level)))
+   ((eq (car s) 'backquote)
+      (backquote-delay-process s (1+ level)))
    (t
     (let ((rest s)
 	  item firstlist list lists expression)
@@ -177,7 +179,8 @@
                   ;; unquote since this needs to go recursively through
                   ;; backquote-process.
                   (not (or (eq (car rest) backquote-unquote-symbol)
-                           (eq (car rest) backquote-backquote-symbol))))
+                           (eq (car rest) backquote-backquote-symbol)
+                           (eq (car rest) 'backquote))))
 	(setq item (backquote-process (car rest) level))
 	(cond
 	 ((= (car item) 2)

Re: Error in nested backquoting

[Andreas Schwab]

Diego Sevilla Ruiz <dsevilla@ditec.um.es> writes:

> 	In backquote expansion, the symbol for backquote (`) is treated
> specially for nested backquoting, but its alias, backquote (if it is
> intended for it to be used from elisp programs) is not correctly evaluated
> in nesting.

Since backquote expansion is purely syntactical, I don't think the
backquote symbol should have any significance in the process.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: Error in nested backquoting

[Diego Sevilla Ruiz]

On 01/07/13 09:53, Andreas Schwab wrote:
> Diego Sevilla Ruiz <dsevilla@ditec.um.es> writes:
>
>> 	In backquote expansion, the symbol for backquote (`) is treated
>> specially for nested backquoting, but its alias, backquote (if it is
>> intended for it to be used from elisp programs) is not correctly evaluated
>> in nesting.
>
> Since backquote expansion is purely syntactical, I don't think the
> backquote symbol should have any significance in the process.

So does that mean that using `backquote' as a symbol to represent ` is 
disqualified? (As opposed, for example, of either using `quote' or ' for 
quoting.)

	Best regards,
	diego.

-- 
Diego Sevilla Ruiz -- http://ditec.um.es/~dsevilla/ -- dsevilla@um.es _.___
Dep. Ingeniería y Tecnología de Computadores, Facultad de Informática D|TEC
Univ.de Murcia,Campus Espinardo,30080 Murcia (SPAIN),Tel.+34868887571

Re: Error in nested backquoting

[Andreas Schwab]

Diego Sevilla Ruiz <dsevilla@ditec.um.es> writes:

> (As opposed, for example, of either using `quote' or ' for quoting.)

quote and ' are indistinguishable, unlike ` and backquote (the latter
just happens to have the same function binding as `).

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: Error in nested backquoting

[Andreas Röhler]

Am 01.07.2013 13:54, schrieb Andreas Schwab:
> Diego Sevilla Ruiz <dsevilla@ditec.um.es> writes:
[...]

  ` and backquote (the latter
> just happens to have the same function binding as `).
>
> Andreas.
>

Can you tell us what makes the diff in result as example displays?

Thanks,

Andreas