fish shell completions keep-order

Question

How do I use --keep-order ?

My function looks like this:

function filterfile -a file -a word
    grep -i $word $file
    grep -iv $word $file | sponge $file
end

and my completions look like this:

complete -k -c filterfile --require-parameter --no-files -a "(cat (commandline -opc)[2])"
complete -k -c filterfile --require-parameter

Following the documentation "Multiple complete calls with -k result in arguments of the later ones displayed first", but when I press tab for a file path nothing happens

Answer 1

If I understand correctly, you have a function filterfile which takes two arguments, a filename and a word to search for in the file. You would like the first argument to tab-complete as file names, and the second argument to tab-complete as words given in the file from the first argument.

You can do this by using the --condition option (short -n) to complete, documented here. Here we use the helper function __fish_is_first_arg to control when our completions run:

# Complete first argument as files.
complete -c filterfile --condition __fish_is_first_arg --force-files

# Complete remaining arguments as words in the file from the first argument.
complete --keep-order -c filterfile --condition 'not __fish_is_first_arg' --no-files -a '(cat (__fish_first_token))'

Now the first argument should tab-complete as files, and the second+ arguments should tab-complete as words found in the file named by the first argument.

(Note that __fish_is_first_arg is an ordinary fish function that ships with fish.)

To answer your original question, the --keep-order option offers completions in the order they are printed, instead of sorting. With --keep-order:

> cat words.txt
sweater
handy
scarecrow
card
geese

> filterfile words.txt <tab>
sweater  handy  scarecrow  card  geese

The completions appear in their original order. Without:

> filterfile words.txt <tab>
card  geese  handy  scarecrow  sweater

the completions are sorted alphabetically.