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* rx of (any SET...)
@ 2022-08-17 15:43 Michael Albinus
  2022-08-17 17:13 ` [External] : " Drew Adams
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Michael Albinus @ 2022-08-17 15:43 UTC (permalink / raw)
  To: help-gnu-emacs

Hi,

I have the regexp

--8<---------------cut here---------------start------------->8---
(concat "[^" (bound-and-true-p mm-7bit-chars) "]")
--8<---------------cut here---------------end--------------->8---

I want to write it in rx notation, but I fail. I know how to use xr for
reverse engineering, but I'd like to keep the variable mm-7bit-chars in
the rx notation, and not to replace it by the literal string.

How would this look like?

Best regards, Michael.



^ permalink raw reply	[flat|nested] 8+ messages in thread

* RE: [External] : rx of (any SET...)
  2022-08-17 15:43 rx of (any SET...) Michael Albinus
@ 2022-08-17 17:13 ` Drew Adams
  2022-08-17 18:19   ` Michael Albinus
  2022-08-17 20:34 ` Michael Heerdegen
  2022-08-17 20:42 ` Harald Jörg
  2 siblings, 1 reply; 8+ messages in thread
From: Drew Adams @ 2022-08-17 17:13 UTC (permalink / raw)
  To: Michael Albinus, help-gnu-emacs@gnu.org

> I have the regexp
> (concat "[^" (bound-and-true-p mm-7bit-chars) "]")

Dunno about rx.  But what happens when `mm-7bit-chars'
isn't bound and true?  Your string is then "[^]", not
a valid regexp.  (Maybe you take care of that elsewhere?)



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [External] : rx of (any SET...)
  2022-08-17 17:13 ` [External] : " Drew Adams
@ 2022-08-17 18:19   ` Michael Albinus
  0 siblings, 0 replies; 8+ messages in thread
From: Michael Albinus @ 2022-08-17 18:19 UTC (permalink / raw)
  To: Drew Adams; +Cc: help-gnu-emacs@gnu.org

Drew Adams <drew.adams@oracle.com> writes:

Hi Drew,

> Dunno about rx.  But what happens when `mm-7bit-chars'
> isn't bound and true?  Your string is then "[^]", not
> a valid regexp.  (Maybe you take care of that elsewhere?)

In practice, it always works. This is because this check is used in
tramp-bug, while composing the message. And while composing the message,
package mm-bodies is already loaded. Using bound-and-true-p is just for
pacifying the byte compiler.

This code snippet is 20 years old. Time to replace bound-and-true-p by
(defvar mm-7bit-chars)

But the question remains: how to express (concat "[^" mm-7bit-chars "]")
in rx notation?

Best regards, Michael.



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: rx of (any SET...)
  2022-08-17 15:43 rx of (any SET...) Michael Albinus
  2022-08-17 17:13 ` [External] : " Drew Adams
@ 2022-08-17 20:34 ` Michael Heerdegen
  2022-08-17 21:37   ` Michael Heerdegen
  2022-08-17 20:42 ` Harald Jörg
  2 siblings, 1 reply; 8+ messages in thread
From: Michael Heerdegen @ 2022-08-17 20:34 UTC (permalink / raw)
  To: help-gnu-emacs

Michael Albinus <michael.albinus@gmx.de> writes:

> (concat "[^" (bound-and-true-p mm-7bit-chars) "]")
>
> I want to write it in rx notation, but I fail. I know how to use xr for
> reverse engineering, but I'd like to keep the variable mm-7bit-chars in
> the rx notation, and not to replace it by the literal string.

C-h f rx RET:
| (regexp EXPR) Match the string regexp from evaluating EXPR at run time.

That's exactly what you are looking for...correct?


(the other) Michael




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: rx of (any SET...)
  2022-08-17 15:43 rx of (any SET...) Michael Albinus
  2022-08-17 17:13 ` [External] : " Drew Adams
  2022-08-17 20:34 ` Michael Heerdegen
@ 2022-08-17 20:42 ` Harald Jörg
  2022-08-18  9:44   ` Michael Albinus
  2 siblings, 1 reply; 8+ messages in thread
From: Harald Jörg @ 2022-08-17 20:42 UTC (permalink / raw)
  To: Michael Albinus; +Cc: help-gnu-emacs

Michael Albinus writes:

> Hi,
>
> I have the regexp
>
> (concat "[^" (bound-and-true-p mm-7bit-chars) "]")
>
> I want to write it in rx notation, but I fail. I know how to use xr for
> reverse engineering, but I'd like to keep the variable mm-7bit-chars in
> the rx notation, and not to replace it by the literal string.
>
> How would this look like?

I found that variables can be included in rx forms with some form of
eval, or by using rx-to-string, which is a function and not a macro.

With the value of mm-7bit-chars at macro expansion time:
(rx (eval `(not (any ,mm-7bit-chars))))

With the value of mm-7bit-chars at runtime:
(eval `(rx (not (any ,mm-7bit-chars))))
(rx-to-string `(not (any ,mm-7bit-chars)))

--
Cheers,
haj



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: rx of (any SET...)
  2022-08-17 20:34 ` Michael Heerdegen
@ 2022-08-17 21:37   ` Michael Heerdegen
  2022-08-18  0:59     ` Michael Heerdegen
  0 siblings, 1 reply; 8+ messages in thread
From: Michael Heerdegen @ 2022-08-17 21:37 UTC (permalink / raw)
  To: help-gnu-emacs

Michael Heerdegen <michael_heerdegen@web.de> writes:

> | (regexp EXPR) Match the string regexp from evaluating EXPR at run time.
>
> That's exactly what you are looking for...correct?

But ok, you have a string that contains a list of chars, so I too have
no better idea than

  (rx (regexp (concat "[^" (bound-and-true-p mm-7bit-chars) "]")))

or to use the function instead:

  (rx-to-string `(not (any ,@mm-7bit-chars)))

What makes sense depends on the context.

Michael.




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: rx of (any SET...)
  2022-08-17 21:37   ` Michael Heerdegen
@ 2022-08-18  0:59     ` Michael Heerdegen
  0 siblings, 0 replies; 8+ messages in thread
From: Michael Heerdegen @ 2022-08-18  0:59 UTC (permalink / raw)
  To: help-gnu-emacs

Michael Heerdegen <michael_heerdegen@web.de> writes:

> (rx (regexp (concat "[^" (bound-and-true-p mm-7bit-chars) "]")))

Even using `rx-define' is not so helpful (its expanding mechanism is
different from e.g. defmacro):

#+begin_src emacs-lisp
  (rx-define any-char (&rest string) (regex (concat "[" string "]")))
  (rx-define not-any-char (&rest string) (regex (concat "[^" string "]")))
#+end_src

Will not work inside `not'.  Thus two definitions.

Ok, in the end I could not really help at all...

Michael.




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: rx of (any SET...)
  2022-08-17 20:42 ` Harald Jörg
@ 2022-08-18  9:44   ` Michael Albinus
  0 siblings, 0 replies; 8+ messages in thread
From: Michael Albinus @ 2022-08-18  9:44 UTC (permalink / raw)
  To: Harald Jörg; +Cc: help-gnu-emacs

Harald Jörg <haj@posteo.de> writes:

Hi Harald,

> I found that variables can be included in rx forms with some form of
> eval, or by using rx-to-string, which is a function and not a macro.
>
> With the value of mm-7bit-chars at macro expansion time:
> (rx (eval `(not (any ,mm-7bit-chars))))
>
> With the value of mm-7bit-chars at runtime:
> (eval `(rx (not (any ,mm-7bit-chars))))
> (rx-to-string `(not (any ,mm-7bit-chars)))

Thanks, that does the trick!

> Cheers,
> haj

Best regards, Michael.



^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2022-08-18  9:44 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-08-17 15:43 rx of (any SET...) Michael Albinus
2022-08-17 17:13 ` [External] : " Drew Adams
2022-08-17 18:19   ` Michael Albinus
2022-08-17 20:34 ` Michael Heerdegen
2022-08-17 21:37   ` Michael Heerdegen
2022-08-18  0:59     ` Michael Heerdegen
2022-08-17 20:42 ` Harald Jörg
2022-08-18  9:44   ` Michael Albinus

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