feat: enable telescope customization for vim.ui.select caller

README.md

@@ -16,6 +16,7 @@ options in the functions. Customization will be done entirely using a separate
 - [Installation](#installation)
 - [Configuration](#configuration)
 - [Advanced configuration](#advanced-configuration)
+- [Notes for plugin authors](#notes-for-plugin-authors)
 - [Alternative and related projects](#alternative-and-related-projects)
 
 ## Requirements
@@ -265,6 +266,35 @@ require('dressing').setup({
 
 ```
 
+## Notes for plugin authors
+
+TL;DR: you can customize the telescope `vim.ui.select` implementation by passing `telescope` into `opts`.
+
+The `vim.ui` hooks are a great boon for us because we can now assume that users
+will have a reasonable UI available for simple input operations. We no longer
+have to build separate implementations for each of fzf, telescope, ctrlp, etc.
+The tradeoff is that `vim.ui.select` is less customizable than any of these
+options, so if you wanted to have a preview window (like telescope supports), it
+is no longer an option.
+
+My solution to this is extending the `opts` that are passed to `vim.ui.select`.
+You can add a `telescope` field that will be passed directly into the picker,
+allowing you to customize any part of the UI. If a user has both dressing and
+telescope installed, they will get your custom picker UI. If either of those
+are not true, the selection UI will gracefully degrade to whatever the user has
+configured for `vim.ui.select`.
+
+An example of usage:
+
+```lua
+vim.ui.select({'apple', 'banana', 'mango'}, {
+  prompt = "Title",
+  telescope = require("telescope.themes").get_cursor(),
+}, function(selected) end)
+```
+
+For now this is available only for the telescope backend, but feel free to request additions.
+
 ## Alternative and related projects
 
 - [telescope-ui-select](https://github.com/nvim-telescope/telescope-ui-select.nvim) - provides a `vim.ui.select` implementation for telescope

lua/dressing/select/telescope.lua

@@ -28,7 +28,7 @@ M.select = function(config, items, opts, on_choice)
     picker_opts = themes.get_dropdown()
   end
 
-  pickers.new(picker_opts, {
+  local defaults = {
     prompt_title = opts.prompt,
     previewer = false,
     finder = finders.new_table({
@@ -41,7 +41,7 @@ M.select = function(config, items, opts, on_choice)
         local selection = state.get_selected_entry()
         local callback = on_choice
         -- Replace on_choice with a no-op so closing doesn't trigger it
-        on_choice = function() end
+        on_choice = function(_, _) end
         actions.close(prompt_bufnr)
         if not selection then
           -- User did not select anything.
@@ -66,7 +66,14 @@ M.select = function(config, items, opts, on_choice)
 
       return true
     end,
-  }):find()
+  }
+
+  -- Hook to allow the caller of vim.ui.select to customize the telescope opts
+  if opts.telescope then
+    pickers.new(opts.telescope, defaults):find()
+  else
+    pickers.new(picker_opts, defaults):find()
+  end
 end
 
 return M