[idea] External custom themes with auto_switch

[olimorris]

idea / problem

herdr has a number of builtin themes and the ability for a user to define their own custom theme (theme.custom.*). herdr also allows you to specify a light and a dark theme.

However, herdr does not allow you to specify a light and a dark theme for a custom theme that sits outside of the users ~/.config/herdr/config.toml.

requested change

herdr to support external themes in a user's config, enabling a config like:

# resolves themes from ~/.config/herdr/themes
[theme]
name = "my_custom_theme" 

# or
auto_switch = true
dark_name = "my_custom_dark_theme"
light_name = "my_custom_light_theme"

This would also allow users to share themes on https://herdr.dev/plugins/

why you want this

I have my own custom theme that I use across macOS, my terminal and Neovim that has light and dark variants. It generates and stores themes for many different apps like ghostty, lazygit, opencode, tmux etc in ~/.cache/nvim/dotfiles/*. For those applications, its trivial to point them (or symlink) them so their respective configs can consume them.

I can specify a single light OR dark theme in my config currently, but if other users who use my custom theme want to do the same, they have to copy and paste a chunk of [theme.custom] into their own config rather than point to a custom theme on disk.

references

• Ghostty's authoring a custom theme
• Wezterms' defining a Color Scheme in a separate file
• Opencode's custom theme - hierarchy