Custom formatter source

[AckslD]

I'm trying to setup a custom formatter source with autopep8 for python but can't get it to work. I first tried:

null_ls.helpers.formatter_factory({
    command = 'autopep8',
})

but looking at the source files this doesn't seem to be exposed anymore. So instead I tried:

null_ls.formatter({
    command = 'autopep8',
})

which doesn't give any error.

But I wasn't sure exactly how to now use this source. Should one just do:

local null_ls = require('null-ls')
null_ls.config({
    sources = {
        null_ls.formatter({
            command = 'autopep8',
        }),
    },
})

?

Doing the above does not seem to work for me. Is it supposed to?

Also is there some way to see the currently active sources?

Thanks in advance!

[jose-elias-alvarez]

Try the following:

local autopep8 = {
    method = null_ls.methods.FORMATTING,
    filetypes = { "python" },
    generator = null_ls.formatter({
        command = "autopep8",
        args = { "-" },
        to_stdin = true,
    }),
}
null_ls.config({
    sources = {
        autopep8,
    },
})

We'd be happy to have you contribute autopep8 as a built-in formatter, too, if that's something you're interested in (at the moment, making built-ins is easier than setting up custom sources, to be honest).

For your second question: Not at the moment, but I'd like to add something like nvim-lspconfig's :LspInfo to show currently available sources. I'll open up an issue to remind myself.

[AckslD]

Thanks a lot @jose-elias-alvarez! That does indeed work 👍

Just out of curiosity why doesn't

local autopep8 = {
    method = null_ls.methods.FORMATTING,
    filetypes = { "python" },
    generator = null_ls.formatter({
        command = "autopep8",
    }),
}
null_ls.config({
    sources = {
        autopep8,
    },
})

work? Ie without args and to_stdin? I thought this would then just do something like autopep8 %.

I opened a PR to add autopep8 here: #96

Re something like :LspInfo, I think that would be awesome!

[jose-elias-alvarez]

Thanks for the PR! I thought about having defaults, but formatter behavior is too unpredictable. For example, if a formatter doesn't support stdin and we run it with these defaults, it might format and write the file to the disk, which will cause weirdness in Neovim. I think it's better to be explicit, even if it requires a little more verbosity.