exclude_func for users to discern when the scrollbar renders

[levouh]

There might be some issues here with the fact that we are using the current window/buffer (#8 and #6) so leaving this as a draft for now as fixes might need to come before this.

Closes #7

[levouh]

This is a little bit confusing (at least as I think about it) to have a function that returns "if the scrollbar should not be drawn". Perhaps it would be a better idea to have the option mirror the name of the function; just should_render which returns true to draw the window and false to not.

[tbung]

I think exclude_func works well with exclude_filetype and exclude_buftype, but if it is named like that it should probably return false by default, because it does not exclude, it should then be switched in should_render.

[petertriho]

I'm not sure if it'll be better/worse but something like render_callback, and just a bare return if we don't want to render could work as well

[levouh]

I assume you mean passing a function that the user can just call if they want to draw the scrollbar @petertriho? I changed it to return whether or not the scrollbar should be drawn, rather than the double negative that existed before that makes it a bit confusing.

[petertriho]

What I mean is something like

M.render = function()
       vim.api.nvim_buf_clear_namespace(0, NAMESPACE, 0, -1)
       config.render_callback(config)

		.... etc
end

config.render_callback = function()
       if vim.tbl_contains(config.excluded_filetypes, vim.bo.filetype) then
            return
       end
end

But the currently discussed should_render way works too. Might be easier/cleaner with the should_render so we can implement both excluded_filestypes and included_filestypes (probably should change these to exclude_filetypes, include_filestypes, exclude_buftypes and include_buftypes

[levouh]

I actually think the implementation to show/hide this works in the same manner as @tbung mentioned. I can just set show = false and then setup autocommands to show the scrollbar when I want it shown.

Let me know if you still want to add something like this and I can take a stab at doing it here.