[question] elegant way to call function in an previous instead of call script file about fzf HOT 5 OPEN

hmmm.... I realized that maybe I can use --nth to prevent call function/scripts to show {1} in list, and {2} in previous, and it indeed works :

$ env |
  sed -r 's/^([a-zA-Z0-9_-]+)=(.*)$/\1 \2/' |
  fzf --delimiter=' ' \
      --preview='source ~/.marslo/bin/bash-color.sh; echo -e "$(c Ys)>> {1}$(c)\n$(c Wi).. {2}$(c)"' \
      --with-nth=1

but I'm still curious how to call function instead of scripts, for more complex process to preview

from fzf.

suddenly realized that, I'm struggling for so long is because of " and ' are different behavior in --preview !

I was using " ( double quotes ) in the very beginning, and it's not working, so I decided to using function instead of cmd. Accidental I was using ' ( single quote ) and it worked !!

here are details:

• double quotes

  $ env |
    sed -rn 's/^([a-zA-Z0-9]+)=.*$/\1/p' |
    fzf --preview-window 'up,30%,wrap,rounded' \
        --preview "_i={}; echo ${_i}"

• single quote

  $ env |
    sed -rn 's/^([a-zA-Z0-9]+)=.*$/\1/p' |
    fzf --preview-window 'up,30%,wrap,rounded' \
        --preview '_i={}; echo ${_i}'

details:

my environment:

$ sw_vers
ProductName:		macOS
ProductVersion:		14.2.1
BuildVersion:		23C71

$ bash --version
GNU bash, version 5.2.26(1)-release (x86_64-apple-darwin23.2.0)
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

$ fzf --version
0.45.0 (brew)

from fzf.

I'd like to know whether if any elegant way can handle call a function in --preview instead of call a shell script file

Functions are not visible to child processes unless they are exported with export -f.

#!/usr/bin/env bash
foo() {
	echo foo
}
export -f foo
fzf --preview 'foo'

SHELL="$(which bash)" fzf --preview 'foo'

Alternatives:

1. make it a string and call the variable

foo=$'echo foo'
: | fzf --preview "$foo"

2. place the function in a file and source it

foo() {
     echo foo
}
: | fzf --preview 'source /path/to/file/with/function; foo'

from fzf.

I'd like to know whether if any elegant way can handle call a function in --preview instead of call a shell script file

Functions are not visible to child processes unless they are exported with export -f.

#!/usr/bin/env bash
foo() {
	echo foo
}
export -f foo
fzf --preview 'foo'

export -f foo work like a charm !

Alternatives:

1. make it a string and call the variable

foo=$'echo foo'
: | fzf --preview "$foo"

2. place the function in a file and source it

foo() {
     echo foo
}
: | fzf --preview 'source /path/to/file/with/function'; foo'

for alternatives solution, how to handle fzf get from pip ( | ) ?
i.e.:

$ foo() { echo ${!1}; }

# fzf from `env | sed`:
$ env | sed -rn 's/^([a-zA-Z0-9]+)=.*$/\1/p' | fzf --preview-window 'up,30%,wrap,rounded' --preview "foo {} "

I've tried:

: | env | sed ... | fzf      # < not working
env | sed ... | : | fzf      # < not working

from fzf.

I've tried:

: | env | sed ... | fzf      # < not working
env | sed ... | : | fzf      # < not working

I'm not entirely clear on the problem. The colon :¹ signifies nothing and can be omitted. It's
only useful if you want to initiate fzf with an empty list.

foo=$'input={};echo "${!input}"'
command env | sed -rn 's/^([a-zA-Z0-9]+)=.*$/\1/p' | SHELL=bash fzf --preview "$foo"

from fzf.