Re: checking several headers when splitting mail

[lee <lee@yun.yagibdah.de>]

Ted Zlatanov <tzz@lifelogs.com> writes:

> On Tue, 28 Jun 2011 20:04:58 +0200 Andreas Schwab <schwab@linux-m68k.org> wrote: 
>
> AS> Ted Zlatanov <tzz@lifelogs.com> writes:
>>> On Wed, 15 Jun 2011 22:42:33 +0200 Andreas Schwab <schwab@linux-m68k.org> wrote: 
>>> 
> AS> You either need to make ?+ a word character in
> AS> nnmail-split-fancy-syntax-table, or use ".*\\+491234567".
>>> 
>>> Could you show an example?
>
> AS> Read the doc string of modify-syntax-entry.
>
> So, for those who are interested, it's useful to test fancy splits like
> this:
>
> #+begin_src lisp
> (let ((mytable (copy-syntax-table nnmail-split-fancy-syntax-table)))
>   (when (with-syntax-table mytable
>           (string-match "\\</var/log" "/var/log"))
>     (message "Matches without modification"))
>   (modify-syntax-entry ?/ "w" mytable)
>   (when (with-syntax-table mytable
>           (string-match "\\</var/log" "/var/log"))
>     (message "Matches with modification")))
>
> #+end_src
>
> Would that be useful in the manual as a demonstration of what a word
> character will do?

Hm, I guess so.  Adding a reference to some documentation about what a
syntax-table is would be useful, too.

> Now for the next questions: is there any downside to modifying
> `nnmail-split-fancy-syntax-table'?  And why does ".*\\+491234567" work?
> What exactly are we looking at to match against the regular expression,
> in other words, and why does that match when the regular expression is
> ".*\\+491234567" but not otherwise?

And another question: My very first attempt to modify an elisp program
looks like this:


#+begin_src lisp
(let (
      (mytable (copy-syntax-table nnmail-split-fancy-syntax-table))
      (mstrg "/var/log"))
  (when (with-syntax-table mytable
	  (string-match (concat "\\<" mstrg) mstrg))
    (message "'%s' matches '%s'without modification" (concat "\\<" mstrg) mstrg))
  (modify-syntax-entry ?/ "w" mytable)
  (when (with-syntax-table mytable
	  (string-match (concat "\\<" mstrg) mstrg))
    (message "'%s' matches '%s' without modification" (concat "\\<" mstrg) mstrg)))
#+end_src


... and it gives different results for the matching than your code does.
Why?

My idea was to eventually make it a function that can be bound to a
key.  That could be useful when working on splitting rules.


Isn't there a way to make these splitting rules easier so that people
who don't speak elisp can understand how to create them?  Something like


if $h_From: matches root@localhost then
  if $h_Subject: matches "/var/log/.*" then
    save "mail.localhost.sys"
  endif
endif


... won't even need (much) explanation.  Exim does it like this in its
.forward files[1].


[1]: http://www.exim.org/exim-html-current/doc/html/spec_html/filter_ch03.html