vis for vi and fun

By R. S. Doiel, 2024-01-31 (updated: 2024-02-02)

I’ve been looking for a vi editor that my fingers would be happy with. I learned vi when I first encountered Unix in University (1980s). I was a transfer student so didn’t get the “introduction to Unix and Emacs” lecture. Everyone used Emacs to edit programs but Emacs to me was not intuitive. I recall having a heck of a time figuring out how to exit the editor! I knew I needed to learn an editor and Unix fast to do my school work. I head to my college bookstore and found two spiral bound books Unix in a Nutshell and “Vi/Ed in a Nutshell”. They helped remedy my ignorance. I spent the afternoon getting comfortable with Unix and learning the basics in Vi. It became my go to text editor. Somewhere along the line nvi came along I used that. Eventually vim replaced nvi as the default “vi” for most Linux system and adapted again. I like one featured about vim over nvi. vim does syntax highlighting. I routinely get frustrate with vim (my old muscle memory throws me into the help systems, very annoying) so I tend to bounce between nvi and vim depending on how my eyes feel and frustration level.

vis, the vi I wished for

Recently I stumbled on vis. I find it a very interesting vi implementation. Like vim it mostly conforms to the classic mappings of a modal editor built on top of ed. But vis has some nice twists. First it doesn’t try to be a monolithic systems like Emacs or vim. Rather then used an application specific scripting language (e.g. Emacs-lisp, vim-script) it uses Lua 5.2 as its configuration language. For me starting up vis feels like starting up nvi. It is quick and responsive where my typical vim setup feels allot like Visual Studio Code in that it’s loading a whole bunch of things I don’t use.

Had vis just had syntax highlighting I don’t know if I was would switched from vim. neovim is a better vim but I don’t use it regularly and don’t go out of my way to install it. vis has one compelling feature that pushed me over the edge. One I didn’t expect. vis supports structured regular expressions. This is the command language found in Plan 9 editors like sam and Acme. The approach to regexp is oriented around streams of characters rather than lines of characters. It does this by supporting the concept of multiple cursors and operating on selections (note the plural) in parallel. This allows a higher degree of transformation, feels like a stream oriented AWK but with simpler syntax for the things you do all the time. It was easiest enough to learn that my finger quickly adapted to it. It does mean that in command mode my search and replace is different than what I used to type. E.g. changing CRLF to LF

:1,$x/\r/ c//

versus

:1,$s/\r//g

Just enough different to catch someone who is used to vim and nvi unaware.

Be careful what you wish for on Ubuntu

When I decided I want to use vis as my preferred “vi” in went and installed it on all my work Ubuntu boxes. What surprised me was that when you install vis on an Ubuntu system it winds up becoming the default “vi”. That posed a problem because I hadn’t consulted with the other people who use those machines. I thought I would type vis instead of vi to use it. Fortunately Ubuntu also provides a means of fixing which alternative programs can be used for things like “vi”. I reverted the default “vi” to vim for my colleagues using the Ubuntu command update-alternatives (e.g. sudo update-alternatives --config vi). No surprises for them and I still get to use vis, I just type the extra “s”.

Getting to know structured regular expressions and case swapping

A challenge in making the switch to vis is learning a new approach to search and replace. Fortunately Marc Tanner gives you the phrases in his documentation. Searching for “structured regular expressions” leads to Rob Pike’s paper of the same name. The other thing Marc points out is his choices in implementing vis. vis is like vi meets the Sam editor of Plan 9 fame. You can try Plan 9 Sam editor by installing Plan 9 User Space. Understanding Sam made the transition to vis smoother. I recommend reading Rob Pike’s paper on “Structured Regular Expressions”¹, his “Sam Tutorial”² then keeping the “Sam Cheatsheet”³ handy during the transition. The final challenge I ran into in making the switch is the old vi stand by for flipping case for letters in visual mode. In the old vi you use the tilde key, shift+~. In vis you press g then ~ to change the case on a letter.

A few “thank you” or “how did I stumble on vis?”

I’d like to say thank you to Marc André Tanner for writing vis, Glendix for highlighting it and to OS News contributor pablo_marx for the story Glendix: Bringing the Beauty of Plan 9 to Linux. With this I find my fingers are happier.

Additional resources

Rob Pike’s “structured regular expressions”↩︎
Sam Tutorial ↩︎
Sam Cheat Sheet ↩︎