Re: [RFC PATCH v2] gnus: Add piem-gnus-mid-to-thread

[Kyle Meyer <kyle@kyleam.com>]

Xinglu Chen writes:

> Inserts a string of the whole thread in mbox format.
> ---
> Changes from v1
>
> - Add safety check for major mode and message id before trying to generate
> the mbox file
> - Escape "^From" in the body to prevent ambiguity

I played around with this a bit, and all series seemed to get applied
without issues.  I think interface-wise it'd be a bit nicer if we could
do this work behind the scenes without the user seeing any changes in
the layout/rendering of Gnus buffers, but I'm not sure that's really
feasible.

> diff --git a/piem-gnus.el b/piem-gnus.el
> index 5f10be8..828ce1f 100644
> --- a/piem-gnus.el
> +++ b/piem-gnus.el
> @@ -55,8 +55,38 @@
>              (match-string 1 mid)
>            mid)))))
>  
> -;; If there is an easy way to generate an mbox for a thread in Gnus, a
> -;; function for `piem-mid-to-thread-functions' should be defined.
> +(defun piem-gnus-mid-to-thread (mid)
> +  (when (and (derived-mode-p 'gnus-summary-mode)
> +	     (string-equal (substring
> +			    (mail-header-id (gnus-summary-article-header))
> +			    1 -1)	; Remove "<" and ">"
> +			   mid))

Great, thanks for adding those guards.

> +    (save-excursion
> +      ;; Cursor has to be at the root of the thread
> +      (gnus-summary-refer-parent-article most-positive-fixnum)
> +      (let ((articles (gnus-summary-articles-in-thread))
> +	    message

I'm going to s/message/&s/ on apply.  It's a cosmetic nit, but I'll trip
over this whenever I need to revisit this code if I don't make that
change.

> +	    ;; Just show raw message
> +	    (gnus-have-all-headers t)
> +	    gnus-article-prepare-hook
> +	    gnus-article-decode-hook
> +	    gnus-display-mime-function
> +	    gnus-break-pages)

When compiling, this gives the following warnings:

  In toplevel form:
  piem-gnus.el:58:1:Warning: Unused lexical variable
      ‘gnus-display-mime-function’
  piem-gnus.el:58:1:Warning: Unused lexical variable ‘gnus-article-decode-hook’
  piem-gnus.el:58:1:Warning: Unused lexical variable ‘gnus-article-prepare-hook’

I'll silence those by adding

  (require 'gnus-art)

> +	(mapc (lambda (article)
> +		(gnus-summary-display-article article)
> +		(push (format
> +		       "From mboxrd@z Thu Jan  1 00:00:00 1970\n%s\n"
> +		       (replace-regexp-in-string ; From-munge
> +			"^From "
> +			"^>From "

There's a spurious "^" making it into the replacement.  Also this
doesn't handle mboxrd's ">From " escaping.  I'll squash the following
in.

diff --git a/piem-gnus.el b/piem-gnus.el
index 4293049..d81c086 100644
--- a/piem-gnus.el
+++ b/piem-gnus.el
@@ -77,8 +77,8 @@ (defun piem-gnus-mid-to-thread (mid)
                 (push (format
                        "From mboxrd@z Thu Jan  1 00:00:00 1970\n%s\n"
                        (replace-regexp-in-string ; From-munge
-                        "^From "
-                        "^>From "
+                        "^>*From "
+                        ">\\&"
                         (with-current-buffer gnus-article-buffer
                           (buffer-substring-no-properties
                            (point-min)

> +			(with-current-buffer gnus-article-buffer
> +			  (buffer-substring-no-properties
> +			   (point-min)
> +			   (point-max)))))
> +		      message))
> +	      articles)
> +	(lambda ()
> +	  (insert (apply #'concat (nreverse message))))))))

Mostly just thinking aloud: this could be rewritten without concat by
using (dolist ... (insert ...)), and it might eventually be worth
considering building the mbox up in a temporary buffer rather than as a
list of strings.  But I think it's fine as is.

Also, I've replaced the tabs with spaces.  Sorry for not having set
indent-tabs-mode for the project.  I've now done that in 9d60b3e.

Pushed (c9228b9).

Thank you!