creating gnus-user-format-function- to shorten group name

creating gnus-user-format-function- to shorten group name

[Jack Vinson]

I've taken up the challenge to create a function which will shorten 
a newsgroup name only when the name is longer than I desire.  It wasn't
really that hard.

I took gnus-short-group-name as a starting point and came up with the code
below.  However, when I created a gnus-user-format-function- for it, I
got an error that 'gnus-tmp-header was not defined.  I also do not know how
to extract the length parameter from the format specification.

I can correct the problem with 'gnus-tmp-header, see my patch for gnus.el.

To use my function as a gnus-user-format-function-, I've created a new
variable to hold the maximum length of a group name, and define the
function for a %uc parameter.

(defvar jmv-gnus-short-group-name-length 30 
  "Maximum length of shortened newsgroup name.  Gnus will abbreviate group
name components until this length or less.")

(defun gnus-user-format-function-c (group)
  (jmv-gnus-contract-group-name group jmv-gnus-short-group-name-length))

(defun jmv-gnus-contract-group-name (group name-length)
  "Collapse GROUP name down to NAME-LENGTH."
  (if (> (length group) name-length) 
      (let* ((name "") (foreign "") (depth 0) (skip 1)
	     )
	(if (string-match ":" group)
	    (setq foreign (substring group 0 (match-end 0))
		  group (substring group (match-end 0))))
	(while group
	  (if (and (> (+ (length name) (length group)) name-length)
		   (string-match "\\." group))
	      (setq name (concat name (substring group 0 1))
		    group (substring group (match-end 0))
		    name (concat name "."))
	    (setq name (concat foreign name group)
		  group nil)))
	name)
    group)
  )

-- 
Jack Vinson                                                  Sunderland, MA
jvinson@cheux.ecs.umass.edu    <http://www.cis.upenn.edu/~vinson/home.html>
"There's balogna in our slacks."