Custom fuzzy completion for commands that are not first in the pipeline ($LBUFFER)

[balta2ar]

Checklist

• I have read through the manual page (man fzf)
• I have searched through the existing issues
• For bug reports, I have checked if the bug is reproducible in the latest version of fzf

Output of fzf --version

0.56.0 (ff16877)

OS

• Linux
• macOS
• Windows
• Etc.

Shell

• bash
• zsh
• fish

Problem / Steps to reproduce

This must have been discussed somewhere during the fzf history, but I can't seem to find any relevant issues or a clear statement that it's not possible in man or on github or wiki (https://github.com/junegunn/fzf/wiki/Examples-(completion)#writing-custom-fuzzy-completion) 😞

I'm trying to make a custom completion for llm command to complete available LLM models:

git di | llm -m **<cursor>

A naive handler is simply not triggered:

_fzf_complete_llm() {
  ARGS="$@"
  if [[ $ARGS == 'llm'* ]]; then
...

or to be more precise, instead, git handler is triggered (which I have a custom handler for):

_fzf_complete_git() {
    ARGS="$@"
...

so it looks like everything that has to do with that type of completion works under the assumption that the command we're completing is the first one? So how can I have a handler for command that is not the first one in the pipeline? Is that possible at all?

I guess I could in that specific case override my git handler, make it more smart at parsing the whole line and check where the "cursor" is, but what if it's a different command I don't have a handler for, e.g.:

xclip -o -selection clibboard | llm --system "translate to english" -m **<cursor>

[LangLangBart]

It does work correctly in bash.

command env -i HOME=$HOME TERM=$TERM USER=$USER PATH=$PATH bash --norc
eval "$(fzf --bash)"

_fzf_complete_doge() {
  _fzf_complete --multi --reverse --prompt="doge> " -- "$@" < <(
    echo very
    echo wow
    echo such
    echo doge
  )
}
complete -F _fzf_complete_doge -o default -o bashdefault doge

[cmd1] | doge **

---

In zsh, the issue lies in the __fzf_extract_command function, which processes commands from left to right until the first command meets the requirement.

fzf/shell/completion.zsh

Lines 123 to 135 in d938fdc

	# Extract the name of the command. e.g. foo=1 bar baz**<tab>
	__fzf_extract_command() {
	local token tokens
	tokens=(${(z)1})
	for token in $tokens; do
	token=${(Q)token}
	if [[ "$token" =~ [[:alnum:]] && ! "$token" =~ "=" ]]; then
	echo "$token"
	return
	fi
	done
	echo "${tokens[1]}"
	}

As a workaround, you could try using process substitution so your intended command is placed first.

# process substitution
paste -sd ","  <(seq 15 -5 1)  
# 15,10,5

# process substitution with redirection
paste -sd "," - < <(seq 15 -5 1)
# 15,10,5

PS: Your reported issue is still valid, don't close it.

[LangLangBart]

PS: Your reported issue is still valid, don't close it.

Based on the description from OP, I didn't search for other tickets until I clicked on the bug icon added by the maintainer to see open bug issues. Now, I would argue to close it as a duplicate of #1992.

[junegunn]

@LangLangBart Oh, thanks for pointing it out.