10.4 Formatting Variables

Throughout this manual you’ve probably noticed lots of variables called things like gnus-group-line-format and gnus-summary-mode-line-format. These control how Gnus is to output lines in the various buffers. There’s quite a lot of them. Fortunately, they all use the same syntax, so there’s not that much to be annoyed by.

Gnus does not use the font locking machinery used by most modes in Emacs, so switching font-lock-mode on in the Gnus group/summary/article buffers usually doesn’t do anything useful—instead it’ll just mess up the faces that Gnus has already put in the buffer. (This is also the case for other minor modes that use the font locking machinery, like whitespace-mode.)

Here’s an example format spec (from the group buffer): ‘%M%S%5y: %(%g%)\n’. We see that it is indeed extremely ugly, and that there are lots of percentages everywhere.

Currently Gnus uses the following formatting variables: gnus-group-line-format, gnus-summary-line-format, gnus-server-line-format, gnus-topic-line-format, gnus-group-mode-line-format, gnus-summary-mode-line-format, gnus-article-mode-line-format, gnus-server-mode-line-format, and gnus-summary-pick-line-format.

All these format variables can also be arbitrary elisp forms. In that case, they will be evaled to insert the required lines.

Gnus includes a command to help you while creating your own format specs. M-x gnus-update-format will eval the current form, update the spec in question and pop you to a buffer where you can examine the resulting Lisp code to be run to generate the line.