Hacking-up-your-own-shell-completion-Computing-wit #

I’ve often used fzf as a file finder, you can simply run something like git ls-files | fzf, and pass the output to your editor, and you’ve already made a git aware fuzzy file finder, running this inside your editor like fzf-vim makes this even more powerful. One quick solution to our doer problem is to write a bash script like this:

#!/bin/bash
doer $(doer -list | fzf)

Here we just use command substitution to run doer’s list command, pass it to fzf, then run doer with the result. Okay fine, I guess I can add proper shell completion to the command using fish’s built in complete command, add it to the repo, and set up an install script. What if there was a way to strap an fzf completion thing into my shell, that I fully control through just a couple lines of fish script, that doesn’t interfere with built-in completion, and allows me to quickly add bindings to any command I frequently run?

function fzf-smart-completion -d "List files and folders"
set -l commandline (__fzf_parse_commandline)
set -l dir $commandline[1]
set -l fzf_query $commandline[2]
# use our cool new completion checker
set -l FZF_CMD (get-completion-command); or return
# fzf edge case and formatting (prevents fzf from taking up the whole screen)
set FZF_HEIGHT 40%
begin
set -lx FZF_DEFAULT_OPTS "--height $FZF_HEIGHT --reverse $FZF_DEFAULT_OPTS $FZF_CMD[2]"
eval "$FZF_CMD[1] | "(__fzfcmd)' -m --query "'$fzf_query'"' | while read -l r; set result $result $r; end
end
if [ -z "$result" ]
commandline -f repaint
return
else
# Remove last token from commandline.
commandline -t ""
end
for i in $result
commandline -it -- (string escape $i)
commandline -it -- ' '
end
commandline -f repaint
end
bind -M insert \et fzf-smart-completion
bind \et fzf-smart-completion

With this little bit of fish scripting, we now have a pretty cool ALT-T command that runs our own fuzzy autocomplete like so.

function get-completion-command
set -l cmd (commandline)
switch $cmd
case 'doer *'
echo 'doer -list'
case 'go test *'
echo 'git ls-files | grep _test.go'
case 'yarn test *'
echo 'git ls-files | grep .test.ts'
case '*'
return 1
end
end

You can see the go tester in action here: Another useful thing I’ve found is automating some routine git commands.