May 8, 2021

Emacs smart-mode-Line and whitelisting wc-mode

There’s a lot of stuff in the default emacs modeline, particularly once you start adding a bunch of useful minor modes like show-paren-mode, smartparens-mode, aggressive-indent-mode, which-key, helm, company-mode etc etc… I honestly don’t find it useful to have access to all that information in the modeline, (if I need to know what’s active, I can just run C-h m). There’s a couple of packages specifically designed to shrink or remove minor mode indicators from your mode line (diminish, delight…) but I don’t really want to have to explicitly set an option for each minor mode. I don’t want any of them to show up! Or almost any of them, at least.

So I settled on using smart-mode-line which uses rich-minority to modify what minor modes get put on the mode line. There’s two ways to go: provide a blacklist of modes to remove, or provide a whitelist of modes to keep in. I’ve gone for the latter approach. The only minor mode I want to display in the modeline is wc-mode. This is basically a word count of your current buffer displayed in the modeline.

rich-minority basically works by just pattern matching what’s in the list of minor mode indicators in minor-mode-alist. This is easy for all the modes that display some static text (e.g. WK for which-key). But the whole point of wc-mode is that it displays something that changes. So we need a regular expression that matches the format wc-mode outputs. Here’s something that appears to work.

(setq rm-whitelist '"WC\\[.+?\\]")

That’s a literal “WC”, and then a literal “[” (double escape backslashes because that’s what I saw in rich-minority.el and it seems to work). .+? then matches zero or one of: one or more of: anything. Which is regex for “don’t be greedy”. And then there’s a literal “]” Basically, without the ?, the regex would match WC[1234]foo foo[], which is not what we want. We want to capture the first match only. This wouldn’t work in general to capture everything up to the corresponding close bracket, if nested brackets were allowed, but that’s not going to trip us up for matching output from wc-mode.

I haven’t played around with other settings in smart-mode-line yet, but I’m already really happy with the cleaner look.

© Seamus Bradley 2021–3

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