feat: Actions can now be summed up and center action (#204)

Closes: #182 

* Actions can now be summed up and center action

* fix: Make some complicated changes for metatable

* Update documentation

Co-authored-by: TJ DeVries <devries.timothyj@gmail.com>

3 files changed, 78 insertions, 22 deletions

diff --git a/README.md b/README.md
index 3a77aa0..ec06972 100644
--- a/README.md
+++ b/README.md
@@ -184,23 +184,28 @@ To see the full list of mappings, check out `lua/telescope/mappings.lua` and the
 
 To override ALL of the default mappings, you can use the `default_mappings` key in the `setup` table.
 
-```
- To disable a keymap, put [map] = false
-
-        So, to not map "<C-n>", just put 
-
-            ...,
-            ["<C-n>"] = false,
-            ...,
-
-        Into your config.
-
- Otherwise, just set the mapping to the function that you want it to be.
-
-            ...,
-            ["<C-i>"] = actions.goto_file_selection_split
-            ...,
+```lua
+-- To disable a keymap, put [map] = false
+-- So, to not map "<C-n>", just put
+["<C-n>"] = false,
+-- Into your config.
+
+-- Otherwise, just set the mapping to the function that you want it to be.
+["<C-i>"] = actions.goto_file_selection_split,
+
+-- You can also define your own functions, which then can be mapped to a key
+local function test_action(prompt_bufnr)
+  print("Action was attached with prompt_bufnr: ", prompt_bufnr)
+  -- Enter your function logic here. You can take inspiration from lua/telescope/actions.lua
+end
+["<C-i>"] = test_action,
 
+-- If you want your function to run after another action you should define it as follows
+local test_action = actions._transform_action(function(prompt_bufnr)
+  print("This function ran after another action. Prompt_bufnr: " .. prompt_bufnr)
+  -- Enter your function logic here. You can take inspiration from lua/telescope/actions.lua
+end)
+["<C-i>"] = actions.goto_file_selection_split + test_action
 
 ```
 
@@ -209,6 +214,12 @@ A full example:
 ```lua
 local actions = require('telescope.actions')
 
+-- If you want your function to run after another action you should define it as follows
+local test_action = actions._transform_action(function(prompt_bufnr)
+  print("This function ran after another action. Prompt_bufnr: " .. prompt_bufnr)
+  -- Enter your function logic here. You can take inspiration from lua/telescope/actions.lua
+end)
+
 require('telescope').setup {
   defaults = {
     mappings = {
@@ -218,6 +229,12 @@ require('telescope').setup {
 
         -- Create a new <c-s> mapping
         ["<c-s>"] = actions.goto_file_selection_split,
+
+        -- Add up multiple actions
+        ["<CR>"] = actions.goto_file_selection_edit + actions.center,
+
+        -- You can perform as many actions in a row as you like
+        ["<CR>"] = actions.goto_file_selection_edit + actions.center + test_action,
       },
     },
   }
@@ -379,7 +396,7 @@ Use the telescope.
 
 ## Themes
 
-Common groups of settings can be setup to allow for themes. We have some built in themes but are looking for more cool options. 
+Common groups of settings can be setup to allow for themes. We have some built in themes but are looking for more cool options.
 
 ### Dropdown
 
@@ -395,7 +412,7 @@ Then you can put your configuration into `get_dropdown({})`
 nnoremap <Leader>f :lua require'telescope.builtin'.find_files(require('telescope.themes').get_dropdown({ winblend = 10 }))<cr>
 ```
 
-Themes should work with every `telescope.builtin` function.  
+Themes should work with every `telescope.builtin` function.
 
 If you wish to make theme, check out `lua/telescope/themes.lua`. If you need more features, make an issue :).
 
diff --git a/lua/telescope/actions.lua b/lua/telescope/actions.lua
index 878ac0e..a35ffee 100644
--- a/lua/telescope/actions.lua
+++ b/lua/telescope/actions.lua
@@ -12,6 +12,37 @@ local actions = setmetatable({}, {
   end
 })
 
+local action_mt = {
+  __call = function(t, ...)
+    local values = {}
+    for _, v in ipairs(t) do
+      local result = {v(...)}
+      for _, res in ipairs(result) do
+        table.insert(values, res)
+      end
+    end
+
+    return unpack(values)
+  end,
+
+  __add = function(lhs, rhs)
+    local new_actions = {}
+    for _, v in ipairs(lhs) do
+      table.insert(new_actions, v)
+    end
+
+    for _, v in ipairs(rhs) do
+      table.insert(new_actions, v)
+    end
+
+    return setmetatable(new_actions, getmetatable(lhs))
+  end
+}
+
+local transform_action = function(a)
+  return setmetatable({a}, action_mt)
+end
+
 --- Get the current picker object for the prompt
 function actions.get_current_picker(prompt_bufnr)
   return state.get_status(prompt_bufnr).picker
@@ -51,7 +82,6 @@ end
 
 -- TODO: It seems sometimes we get bad styling.
 local function goto_file_selection(prompt_bufnr, command)
-  local picker = actions.get_current_picker(prompt_bufnr)
   local entry = actions.get_selected_entry(prompt_bufnr)
 
   if not entry then
@@ -90,7 +120,6 @@ local function goto_file_selection(prompt_bufnr, command)
       a.nvim_win_set_config(preview_win, {style = ''})
     end
 
-    local original_win_id = picker.original_win_id or 0
     local entry_bufnr = entry.bufnr
 
     actions.close(prompt_bufnr)
@@ -117,6 +146,10 @@ local function goto_file_selection(prompt_bufnr, command)
   end
 end
 
+function actions.center(_)
+  vim.cmd(':normal! zz')
+end
+
 function actions.goto_file_selection_edit(prompt_bufnr)
   goto_file_selection(prompt_bufnr, "edit")
 end
@@ -185,4 +218,10 @@ actions.insert_value = function(prompt_bufnr)
   return entry.value
 end
 
+for k, v in pairs(actions) do
+  actions[k] = transform_action(v)
+end
+
+actions._transform_action = transform_action
+
 return actions
diff --git a/lua/telescope/mappings.lua b/lua/telescope/mappings.lua
index 561bc8b..766f861 100644
--- a/lua/telescope/mappings.lua
+++ b/lua/telescope/mappings.lua
@@ -16,7 +16,7 @@ mappings.default_mappings = config.values.default_mappings or {
       ["<Down>"] = actions.move_selection_next,
       ["<Up>"] = actions.move_selection_previous,
 
-      ["<CR>"] = actions.goto_file_selection_edit,
+      ["<CR>"] = actions.goto_file_selection_edit + actions.center,
       ["<C-x>"] = actions.goto_file_selection_split,
       ["<C-v>"] = actions.goto_file_selection_vsplit,
       ["<C-t>"] = actions.goto_file_selection_tabedit,
@@ -30,7 +30,7 @@ mappings.default_mappings = config.values.default_mappings or {
 
     n = {
       ["<esc>"] = actions.close,
-      ["<CR>"] = actions.goto_file_selection_edit,
+      ["<CR>"] = actions.goto_file_selection_edit + actions.center,
       ["<C-x>"] = actions.goto_file_selection_split,
       ["<C-v>"] = actions.goto_file_selection_vsplit,
       ["<C-t>"] = actions.goto_file_selection_tabedit,