Set environment variable for tmux and nvim can display current layer, etc.

[thomastthai]

To better integrate Kanata with nvim, tmux, or other programs, it would be helpful for Kanata to allow the setting of system environment variables that other programs can read and act on. For example, it would be nice to know which layer I'm on when changing layers. When Kanata switches or toggles a layer, we could use the multi command to also include setenv KANATA-LAYER nav. We can then customize LuaLine to read that KANATA-LAYER to display on the status line for nvim or write some shell script to use with, tmux statusline, Catppuccin, etc.

Layer info is just one of many useful cases for TUI and GUI.

[jtroo]

There are already various integration points with external programs.

• TCP server:
  • https://github.com/search?q=repo%3Ajtroo%2Fkanata+tcp+server&type=discussions
  • https://github.com/jtroo/kanata/blob/main/tcp_protocol/src/lib.rs
• cmd to execute tmux commands or write strings to files

[thomastthai]

I didn't know Kanata had a TCP server! That's even better!

[thomastthai]

After learning about Kanata's TCP server, I was able to code a NeoVim Lua plugin for Lazy that has a persistent TCP connection to Kanata and can get live layer names. See the "layer" glyph near the lower right corner of the image showing the "base" layer.

I'm new to Lua and NeoVim so the code needs lots of cleaning up, but it works. Once the code is cleaned up, I'll release it.