`fzf` choice support

[nikochiko]

fzf is a popular fuzzy finder tool that can do fuzzy matching within a list of strings (https://github.com/junegunn/fzf)
There should be an easy way to use fzf to display choices for a prompt if it is available (installed by the user).

When there is a large number of choices, the up and down arrows are inconvenient. With fuzzy matching you can type the part of the option that you remember and it will keep narrowing it down. It is not possible to integrate it with click.prompt. It is possible to do it with some other libraries (https://github.com/nk412/pyfzf) - like this one.

I am willing to contribute the code for this

[davidism]

As interesting as that library may be, we do not use third party libraries in Click. Are you referring to refactoring part of Click to make it possible to extend? I'm not really clear what you're proposing.

[nikochiko]

Sorry, I wasn't clear. What I meant was that, it would be really handy to have something like

click.prompt("Please make a choice", choices=get_choices(), use_fzf=True)

That will route the output to fzf if it is there on the system. In that way the CLI will get a neat UI to see the choices and choose one. Similar to opening something in a pager (click.echo_with_pager).

we do not use third party libraries in Click

What I mean is, if use_fzf is true, then click will look for a fzf binary locally. Use it if it exists, or just continue on with normal behaviour if not.

[davidism]

Well, we definitely won't have a use_fzf parameter, since as I said we don't typically add random third part functionality. I do want to allow the developer to override things such as what prompt does, so maybe that will help with your case eventually.

[nikochiko]

allow the developer to override things such as what prompt does, so maybe that will help with your case eventually.

That will help, thanks!

Was typing this before your reply, I think this is similar to what you mentioned:

But I understand that it might not be ideal for click to be this tightly coupled with another library. I am not that familiar with how click's code is written, but would it be possible to have a generic way of passing the choices to some other shell command? Something like

click.prompt("Please make a choice", choices=get_choices, transform=transform_func)

# where transform_func is something like
def transform_func(choices):
    return "fzf ..."

[kdeldycke]

A FAQ entry covering the completion of prompts in Click has been proposed in #3826