How to create a blocking picker?

[enderbeatt]

I am pretty sure I am not the first person who wants to implement something like this: start a picker, select an item, and get an item in lua code. I basically want to have vim.fn.input but with a better UX.

Is there a way to wait for the picker to finish in lua code?

[drowning-cat]

Have you heard of callbacks?

Snacks.picker.pick('files', {
  on_close = function(picker)
    local items = picker:selected { fallback = true }
    vim.print(items)
  end,
})

You can also override the confirm action like this:

Note

Jump is the default action but some pickers may override it. See sources.lua.

Snacks.picker.pick('files', {
  confirm = function(picker, item, action)
    local multi_selection = picker:selected { fallback = true }
    vim.print { item, multi_selection }
    Snacks.picker.actions.jump(picker, item, action)
  end,
})

or like this:

Snacks.picker.pick('files', {
  actions = {
    before_confirm = function(picker, item)
      vim.print(item)
    end,
  },
  win = {
    input = {
      keys = {
        ['<CR>'] = { { 'before_confirm', 'confirm' }, mode = { 'i', 'n' } },
      },
    },
  },
})

There is also a drop-in replacement for the vim.ui.select function:

Snacks.picker.select(items, opts, on_choice)

[enderbeatt]

Yes, I know about callbacks, but I have no idea how to make it blocking:

local str = func_that_starts_a_picker();
-- do something with str

My actual usecase: when I start a dap session and I need to choose an executable, I want to find it in cwd with a snacks picker.

[drowning-cat]

I don't understand why you can't just put your code in the callback. Do you hate callbacks that much? I mean, if the code will only be executed after the picker execution, then just put it in the callback. Or, you can show me the code you're working on, and I'll try to inspect it later.

[enderbeatt]

I do not hate callbacks, it's just that nvim-dap requires a string or a function that returns a string to setup its arguments
Fortunately, turns out that if you pass nvim-dap a function, it will run it inside a coroutine, so that's how I implemented what I need:
https://github.com/enderbeatt/neovim-config/blob/master/lua/handmade/debug_helpers.lua#L40-L65

And that's where I use it:
https://github.com/enderbeatt/neovim-config/blob/master/lua/plugin/debug/config.lua#L40-L42

[drowning-cat]

Yep, that makes sense.

dap.txt > Things to note