folding long lines

[OKAZAKI Tetsurou]

Cc to emacs-mime-en at m17n.org,

In the ML [Wanderlust English 00200] 
Sean Rima <sean at tcob1.net> wrote:

> > At Thu, 10 Oct 2002 22:40:26 +0100, Sean Rima wrote:
> >> Is there a way to fold long lines. I use SpamAssassin and it
> >> creates a very long header line which is not folded so that it is
> >> easily ready. I have to scroll across the screen and this is very
> >> slow. I was wondering if I could tell WL to fold after X characters
...
> Thanks for that. But why does WL ignore the \r\t that is in the line
> anyway. Looking on the imapd machine at the messages the lines are
> folded.

In RFC2822, such line breaks are called as the folding white space (FWS)
and described as below.

  3.2.3. Folding white space and comments

  ... Wherever header folding appears in a message (that is, a header
  field body containing a CRLF followed by any WSP), header unfolding
  (removal of the CRLF) is performed before any further lexical analysis
  is performed on that header field according to this standard. That is
  to say, any CRLF that appears in FWS is semantically "invisible."

Wanderlust uses the FLIM API to decode headers in a Message buffer.
You can change the FLIM's header decode policy by the function
`mime-set-field-decoder'.

For a example, if you want to suppress unfolding of the unstructured
header field body, such as X-Spam-Status, in a message buffer,
please add the following line to your ~/.wl.

  (mime-set-field-decoder 'X-Spam-Status 'wide nil)

Then restart emacs and WL.

Since the current FLIM implementation does not update the cache of
a field decoder mapping immediately when `mime-set-field-decoder' is
invoked (bug?), it is required for you to restart emacs.

-- 
Tetsurou