yafl (yet another fzf launcher)

yafl combines sway-launcher-desktop philosophy with rofi script mode.

Why not rofi or sway-launcher-desktop?

Running rofi on Wayland can be annoying. Rarely it crashes the entire desktop because it steals the keyboard and mouse. Also, pasting into it from other XWayland apps also doesn't work.

sway-launcher-desktop is marvellous because it delegates the display part to a terminal emulator and the search logic to fzf, but it has some downsides. First, it's written in awk/bash and supporting modes would be painful to support (at least for my level of experience).

Above all, I used an excuse to write something in Go, so I created yafl. Being a Go binary, yafl is easier to test and more portable than bash scripts (hello, Windows. But not yet. Right now, it's only Linux).

What's a mode?

yafl returns the entries from a different mode whenever the prefix option matches the search term. When that happens, yafl invokes the command specified by exec option. The script should print the entries separated by \n in stdout. fzf then displays the entries and you can select some of them. yafl will call the same cli, but passing the selected entry as an argument now. This "API" is somewhat compatible with script modefrom rofi. Pretty clever stuff from them 👏!

Additionally, it's possible to delimit the key and value by \x1f, like echo -n 'key\x1fvalue'. Then, when you select the entry from fzf, yafl invokes the script passing the key as the first argument.

More examples are in the examples directory:

• yafl_bookmark: Lists all the bookmarks of a Firefox installation and opens a new tab whenever you find them
• yafl_search: Search by multiple search engines
• yafl_moji: Wraps rofimoji and to list and select emojis

How does it activate the modes?

To know which mode should be activated based on the input, it uses the fzf change:reload option passing yafl search {input} as the argument, i.e. fzf invokes yafl search for every keystroke you press.

Yikes. That's slow.

Invoking the mode script every time brings some overhead. To solve that, by default, yafl caches the mode entries for 60 seconds. I couldn't notice any input lags on my machine, but YMMV.

Cache invalidation shouldn't be an issue, but you can manually call it with:

yafl cache clean mode_key

Running on sway

Copied from sway-launcher-desktop:

for_window [app_id="^yafl"] floating enable, sticky enable, resize set 700 px 500 px, border pixel 10
set $menu exec $term --app-id=yafl -e /home/guilherme/Projects/mine/yafl/yafl
bindsym $mod+d exec $menu

Modes API

Create a file in $HOME/.config/yaml/config.toml with the following options:

# bookmark is the mode key
[modes.bookmark]
# Cache time before yafl executes the script again
cache = 60
# Cli that returns entries searchable by fzf and executes the entry
# \x1f byte is the delimiter between the key and value, but it's not necessary
exec = "bookmarks"
# Input starting with "f <SPC>" activates the mode and shows only the entries of this mode
prefix = "f"
# Ranks the selected entries based on previous selections. Defaults to false
history = true
# Calls the exec cli with the input even if there are no matches. Defaults to false
call_without_match = true

Building

go build
# Requires fzf
./yafl